CALPINE CORP
S-3, 1999-02-18
COGENERATION SERVICES & SMALL POWER PRODUCERS
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<PAGE>   1
 
   AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON FEBRUARY 18, 1999
                                                 REGISTRATION NO. 333-
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                            ------------------------
 
                                    FORM S-3
                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933
                              CALPINE CORPORATION
             [EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER]
 
<TABLE>
<S>                                                 <C>
                     DELAWARE                                              4911
             (STATE OF INCORPORATION)                          (PRIMARY STANDARD INDUSTRIAL
                                                               CLASSIFICATION CODE NUMBER)
</TABLE>
 
                          50 WEST SAN FERNANDO STREET
                               SAN JOSE, CA 95113
                                 (408) 995-5115
    (ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA CODE,
                  OF REGISTRANT'S PRINCIPAL EXECUTIVE OFFICES)
                            ------------------------
 
                                PETER CARTWRIGHT
                     PRESIDENT AND CHIEF EXECUTIVE OFFICER
                              CALPINE CORPORATION
                          50 WEST SAN FERNANDO STREET
                               SAN JOSE, CA 95113
                                 (408) 995-5115
           (NAME, ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER,
                   INCLUDING AREA CODE, OF AGENT FOR SERVICE)
                            ------------------------
 
                                   COPIES TO:
 
<TABLE>
<S>                                                 <C>
              SCOTT D. LESTER, ESQ.                                JOSEPH A. COCO, ESQ.
         BROBECK, PHLEGER & HARRISON LLP                 SKADDEN, ARPS, SLATE, MEAGHER & FLOM LLP
                    ONE MARKET                                       919 THIRD AVENUE
                SPEAR STREET TOWER                               NEW YORK, NY 10022-3897
             SAN FRANCISCO, CA 94105                                  (212) 735-3000
                  (415) 442-0900
</TABLE>
 
        APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC:
  As soon as practicable after this Registration Statement becomes effective.
 
    If the only securities being registered on this Form are being offered
pursuant to dividend or interest reinvestment plans, please check the following
box.  [ ]
 
    If any of the securities being registered on this Form are to be offered on
a delayed or continuous basis pursuant to Rule 415 under the Securities Act of
1933, other than securities offered only in connection with dividend or interest
reinvestment plans, check the following box.  [ ]
 
    If this Form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, please check the following box
and list the Securities Act registration statement number of the earlier
effective registration statement for the same offering.  [ ]
 
    If this Form is a post-effective amendment filed pursuant to Rule 462(c)
under the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering.  [ ]
 
    If delivery of the prospectus is expected to be made pursuant to Rule 434,
please check the following box.  [ ]
 
<TABLE>
<S>                                   <C>                  <C>                  <C>                  <C>
- -------------------------------------------------------------------------------------------------------------------------
- -------------------------------------------------------------------------------------------------------------------------
                                                             PROPOSED MAXIMUM
         TITLE OF EACH CLASS                 AMOUNT         AGGREGATE OFFERING    PROPOSED MAXIMUM
         OF SECURITIES TO BE                 TO BE              PRICE PER        AGGREGATE OFFERING       AMOUNT OF
             REGISTERED                  REGISTERED(1)         SECURITY(2)            PRICE(2)         REGISTRATION FEE
- -------------------------------------------------------------------------------------------------------------------------
  % Senior Notes Due 2004,
  % Senior Notes Due 2006,
  % Senior Notes Due 2009 and
  % Senior Notes Due 2011............     $500,000,000              --              $500,000,000           $139,000
- -------------------------------------------------------------------------------------------------------------------------
Common Stock.........................   6,900,000 shares         $30.469            $210,236,100           $58,446
- -------------------------------------------------------------------------------------------------------------------------
- -------------------------------------------------------------------------------------------------------------------------
</TABLE>
 
(1) Includes 900,000 shares of common stock as to which the underwriters have
    been granted an option to cover over-allotments, if any.
 
(2) The proposed maximum offering price per share and the registration fee were
    calculated in accordance with Rule 457(c) based on the average of the high
    and low prices for the Company's common stock on February 11, 1999, as
    listed on the New York Stock Exchange.
 
    THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATE OR
DATES AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT SHALL
FILE A FURTHER AMENDMENT THAT SPECIFICALLY STATES THAT THIS REGISTRATION
STATEMENT SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH SECTION 8(a) OF
THE SECURITIES ACT OF 1933, AS AMENDED, OR UNTIL THE REGISTRATION STATEMENT
SHALL BECOME EFFECTIVE ON SUCH DATE AS THE SECURITIES EXCHANGE COMMISSION,
ACTING PURSUANT TO SAID SECTION 8(a), MAY DETERMINE.
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
<PAGE>   2
 
                               EXPLANATORY NOTES
 
     This Registration Statement contains two forms of prospectus, one to be
used in connection with the offering of      % Senior Notes due 2004,      %
Senior Notes Due 2006,      % Senior Notes Due 2009 and      % Senior Notes Due
2011 (the "Debt Prospectus") and the other to be used in connection with a
concurrent offering of common stock (the "Equity Prospectus").
<PAGE>   3
 
The information in this prospectus is not complete and may be changed. We may
not sell these securities until the registration statement filed with the
Securities and Exchange Commission is effective. This prospectus is not an offer
to sell these securities and is not soliciting an offer to buy these securities
in any state where the offer or sale is not permitted.
 
                 SUBJECT TO COMPLETION, DATED FEBRUARY 18, 1999
 
                                6,000,000 Shares
 
LOGO                          CALPINE CORPORATION
 
                                  Common Stock
                               ------------------
 
   Our common stock is listed on the New York Stock Exchange under the symbol
                                   "CPN." On
  February   , 1999, the last sale price of the common stock was $          .
 
  The underwriters have an option to purchase a maximum of 900,000 additional
                                shares to cover
                           over-allotments of shares.
 
Concurrently with this offering of common stock, we are offering $500.0 million
                                 of   % Senior
       Notes Due 2004,      % Senior Notes Due 2006,      % Senior Notes
                   Due 2009 and      % Senior Notes Due 2011.
 
INVESTING IN OUR COMMON STOCK INVOLVES CERTAIN RISKS. SEE "RISK FACTORS" ON PAGE
                                       7.
 
<TABLE>
<CAPTION>
                                                               UNDERWRITING     PROCEEDS TO
                                                  PRICE TO    DISCOUNTS AND       CALPINE
                                                   PUBLIC      COMMISSIONS      CORPORATION
                                                  ---------   --------------   --------------
<S>                                               <C>         <C>              <C>
Per Share.......................................  $           $                $
Total...........................................  $           $                $
</TABLE>
 
     Delivery of the shares will be made on or about             , 1999, against
payment in
immediately available funds.
 
     Neither the Securities and Exchange Commission nor any state securities
commission
has approved or disapproved of these securities or determined if this prospectus
is truthful or
complete. Any representation to the contrary is a criminal offense.
 
                           CREDIT SUISSE FIRST BOSTON
 
                  Prospectus dated                     , 1999.
<PAGE>   4
 
                      [Depiction of Delta Energy Center.]
  "Delta Energy Center, a proposed 880 megawatt gas-fired facility located in
                            Pittsburg, California."
 
                      [Depiction of Pasadena Power Plant.]
 "Pasadena Power Plant, a 240 megawatt gas-fired facility located in Pasadena,
                                    Texas."
<PAGE>   5
 
                               TABLE OF CONTENTS
 
<TABLE>
<CAPTION>
                                      PAGE
                                      ----
<S>                                   <C>
PROSPECTUS SUMMARY..................    1
RISK FACTORS........................    7
WHERE YOU CAN FIND MORE
  INFORMATION.......................   16
FORWARD-LOOKING STATEMENTS..........   17
USE OF PROCEEDS.....................   18
PRICE RANGE OF COMMON STOCK.........   19
DIVIDEND POLICY.....................   19
CAPITALIZATION......................   20
SELECTED CONSOLIDATED FINANCIAL
  DATA..............................   21
PRO FORMA CONSOLIDATED FINANCIAL
  DATA..............................   23
MANAGEMENT'S DISCUSSION AND ANALYSIS
  OF FINANCIAL CONDITION AND RESULTS
  OF OPERATION......................   25
</TABLE>
 
<TABLE>
<CAPTION>
                                      PAGE
                                      ----
<S>                                   <C>
BUSINESS............................   36
MANAGEMENT..........................   60
PRINCIPAL STOCKHOLDERS..............   63
DESCRIPTION OF CAPITAL STOCK........   65
DESCRIPTION OF THE SENIOR NOTES.....   67
DESCRIPTION OF CERTAIN OTHER
  INDEBTEDNESS......................   67
UNDERWRITING........................   71
NOTICE TO CANADIAN RESIDENTS........   72
LEGAL MATTERS.......................   73
EXPERTS.............................   74
</TABLE>
 
                               ------------------
 
     YOU SHOULD RELY ONLY ON THE INFORMATION CONTAINED IN THIS DOCUMENT OR TO
WHICH WE HAVE REFERRED YOU. WE HAVE NOT AUTHORIZED ANYONE TO PROVIDE YOU WITH
INFORMATION THAT IS DIFFERENT. THIS DOCUMENT MAY ONLY BE USED WHERE IT IS LEGAL
TO SELL THESE SECURITIES. THE INFORMATION CONTAINED IN THIS DOCUMENT MAY ONLY BE
ACCURATE ON THE DATE OF THIS DOCUMENT.
 
                                        i
<PAGE>   6
 
                               PROSPECTUS SUMMARY
 
     This summary highlights information contained elsewhere in this prospectus.
This summary is not complete and does not contain all of the information that
you should consider before investing in the common stock. You should carefully
read the entire prospectus, including the risk factors, the financial statements
and the documents incorporated by reference into it. The terms "Calpine," "our
company," "our" and "we," as used in this prospectus, refer to Calpine
Corporation and its consolidated subsidiaries.
 
                                  THE COMPANY
 
     Calpine is a leading independent power company engaged in the development,
acquisition, ownership and operation of power generation facilities and the sale
of electricity predominantly in the United States. We have experienced
significant growth in all aspects of our business over the last five years.
Currently, we own interests in 22 power plants having an aggregate capacity of
2,729 megawatts and have three acquisition transactions pending in which we will
acquire 14 geothermal power plants with an aggregate capacity of 694 megawatts
and certain related steam fields. We also have six gas-fired projects under
construction having an aggregate capacity of 1,784 megawatts and have announced
plans to develop four gas-fired power plants with a total capacity of 2,580
megawatts. Upon completion of pending acquisitions and projects under
construction, we will have interests in 40 power plants having an aggregate
capacity of 5,207 megawatts, of which we will have a net interest in 4,271
megawatts. This represents significant growth from the 342 megawatts of capacity
we had at the end of 1993. Of this total generating capacity, 81% will be
attributable to gas-fired facilities and 19% will be attributable to geothermal
facilities.
 
     As a result of our expansion program, our revenues, cash flow, earnings and
assets have grown significantly over the last five years, as shown in the table
below.
 
<TABLE>
<CAPTION>
                                                               COMPOUND ANNUAL
                                        1993         1998        GROWTH RATE
                                      --------    ----------   ---------------
                                      (DOLLARS IN MILLIONS)
<S>                                   <C>         <C>          <C>
Total Revenue.......................   $ 69.9      $  555.9          51%
EBITDA..............................     42.4         255.3          43%
Net Income..........................      3.8          45.7          64%
Total Assets........................    302.3       1,728.9          42%
</TABLE>
 
     Since our inception in 1984, we have developed substantial expertise in all
aspects of the development, acquisition and operation of power generation
facilities. We believe that the vertical integration of our extensive
engineering, construction management, operations, fuel management and financing
capabilities provides us with a competitive advantage to successfully implement
our acquisition and development program and has contributed to our significant
growth over the past five years.
 
                                   THE MARKET
 
     The power industry represents the third largest industry in the United
States, with an estimated end-user market of over $250 billion of electricity
sales in 1998 produced by an aggregate base of power generation facilities with
a capacity of approximately 750,000 megawatts. In response to increasing
customer demand for access to low-cost electricity
                                        1
<PAGE>   7
 
and enhanced services, new regulatory initiatives have been and are continuing
to be adopted at both the state and federal level to increase competition in the
domestic power generation industry. The power generation industry historically
has been largely characterized by electric utility monopolies producing
electricity from old, inefficient, high-cost generating facilities selling to a
captive customer base. Industry trends and regulatory initiatives have
transformed the existing market into a more competitive market where end users
purchase electricity from a variety of suppliers, including non-utility
generators, power marketers, public utilities and others.
 
     There is a significant need for additional power generating capacity
throughout the United States, both to satisfy increasing demand, as well as to
replace old and inefficient generating facilities. Due to environmental and
economic considerations, we believe this new capacity will be provided
predominantly by gas-fired facilities. We believe that these market trends will
create substantial opportunities for efficient, low-cost power producers that
can produce and sell energy to customers at competitive rates.
 
     In addition, as a result of a variety of factors, including deregulation of
the power generation market, utilities, independent power producers and
industrial companies are disposing of power generation facilities. To date,
numerous utilities have sold or announced their intentions to sell their power
generation facilities and have focused their resources on the transmission and
distribution business segments. Many independent producers operating a limited
number of power plants are also seeking to dispose of their plants in response
to competitive pressures, and industrial companies are selling their power
plants to redeploy capital in their core businesses.
 
                                    STRATEGY
 
     Our strategy is to continue our rapid growth by capitalizing on the
significant opportunities in the power market, primarily through our active
development and acquisition programs. In pursuing our proven growth strategy, we
utilize our extensive management and technical expertise to implement a fully
integrated approach to the acquisition, development and operation of power
generation facilities. This approach uses our expertise in design, engineering,
procurement, finance, construction management, fuel and resource acquisition,
operations and power marketing, which we believe provides us with a competitive
advantage. The key elements of our strategy are as follows:
 
     - Development and expansion of power plants. We are actively pursuing the
       development and expansion of highly efficient, low-cost, gas-fired power
       plants to replace old and inefficient generating facilities and meet the
       demand for new generation.
 
     - Acquisition of power plants. Our strategy is to acquire power generating
       facilities that meet our stringent criteria, provide significant
       potential for revenue, cash flow and earnings growth and provide the
       opportunity to enhance the operating efficiencies of the plants.
 
     - Enhancement of the performance and efficiency of existing power
       projects. We continually seek to maximize the power generation potential
       of our operating assets and minimize our operating and maintenance
       expenses and fuel costs.
                                        2
<PAGE>   8
 
                              RECENT DEVELOPMENTS
 
     Project Development and Construction. In July 1998, we achieved a key
milestone in our development program by completing the development of our 240
megawatt gas-fired power plant in Pasadena, Texas. The Pasadena Power Plant
serves as a prototype for future development projects. We currently have six
gas-fired projects under construction, representing an additional 1,784
megawatts of capacity. Of these new projects, we are expanding our Pasadena and
Clear Lake facilities by an aggregate of 545 megawatts. In addition, four new
gas-fired power plants, with a total capacity of 1,239 megawatts, are currently
under construction in Dighton, Massachusetts; Tiverton, Rhode Island; Rumford,
Maine; and Westbrook, Maine. We have also announced plans to develop four
additional power generation facilities, totaling an estimated 2,580 megawatts of
electricity, in California, Texas and Arizona.
 
     Pending Acquisitions. We are currently in the process of completing three
acquisitions comprising 14 geothermal power plants with an aggregate capacity of
694 megawatts and certain related steam fields, located in The Geysers,
California. Historically, we have served as the steam supplier for these
facilities, which have been owned and operated by PG&E. We anticipate that these
acquisitions will enable us to consolidate our operations in The Geysers into a
single ownership structure and to integrate the power plant and steam field
operations, allowing us to optimize the efficiency and performance of the
facilities. We believe that these acquisitions will provide us with significant
synergies that utilize our expertise in geothermal power generation and position
us to benefit from the demand for "green" energy in the competitive market.
                                        3
<PAGE>   9
 
                                  THE OFFERING
 
Common stock offered by
Calpine.........................    6,000,000 shares
 
Common stock to be outstanding
  after the offering............    26,161,581 shares(1)
 
Senior note offering............    Concurrently with the common stock offering,
                                    we are offering (by a separate prospectus)
                                    $500.0 million aggregate principal amount of
                                         % Senior Notes Due 2004,      % Senior
                                    Notes Due 2006,      % Senior Notes Due 2009
                                    and      % Senior Notes Due 2011.
 
Use of proceeds.................    We expect to utilize a portion of the net
                                    proceeds from the offerings as follows: (1)
                                    $119.6 million to refinance indebtedness
                                    relating to the Gilroy Power Plant, (2)
                                    $101.0 million to acquire the steam fields
                                    that service the Sonoma County Power Plants,
                                    (3) $25.0 million to complete the expansion
                                    of the Clear Lake Power Plant and (4)
                                    approximately $400.0 million to finance a
                                    portion of the power generation facilities
                                    currently under construction and the
                                    projects currently under development,
                                    including, but not limited to, the
                                    Westbrook, Sutter, South Point and Magic
                                    Valley power plants. The remaining net
                                    proceeds, if any, will be used for working
                                    capital and general corporate purposes. See
                                    "Use of Proceeds."
 
New York Stock Exchange
symbol..........................    CPN
 
- ---------------
(1) Does not include 2,884,440 shares of common stock subject to issuance upon
    exercise of options previously granted and outstanding as of December 31,
    1998, under our 1996 Stock Incentive Plan.
                                        4
<PAGE>   10
 
      SUMMARY CONSOLIDATED HISTORICAL FINANCIAL AND OPERATING INFORMATION
 
     The following table sets forth a summary of our consolidated historical
financial and operating information for the periods indicated. Our summary
consolidated historical financial information was derived from our consolidated
financial statements. The information presented below should be read in
conjunction with "Selected Consolidated Financial Data" and our consolidated
financial statements, included elsewhere and incorporated by reference in this
prospectus.
 
<TABLE>
<CAPTION>
                                                          YEAR ENDED DECEMBER 31,
                                        ------------------------------------------------------------
                                          1994        1995         1996         1997         1998
                                        --------   ----------   ----------   ----------   ----------
                                                   (IN THOUSANDS, EXCEPT PER SHARE DATA)
<S>                                     <C>        <C>          <C>          <C>          <C>
STATEMENT OF OPERATIONS DATA:
  Total revenue.......................  $ 94,762   $  132,098   $  214,554   $  276,321   $  555,948
  Cost of revenue.....................    52,845       77,388      129,200      153,308      375,327
  Gross profit........................    41,917       54,710       85,354      123,013      180,621
  Project development expenses........     1,784        3,087        3,867        7,537        7,165
  General and administrative
    expenses..........................     7,323        8,937       14,696       18,289       26,780
  Income from operations..............    31,772       42,686       66,791       97,187      146,676
  Interest expense....................    23,886       32,154       45,294       61,466       86,726
  Other (income) expense..............    (1,988)      (1,895)      (6,259)     (17,438)     (13,423)
  Extraordinary charge................        --           --           --           --          641
  Net income..........................  $  6,021   $    7,378   $   18,692   $   34,699   $   45,678
  Diluted earnings per common share:
    Weighted average shares of common
      stock outstanding...............    10,921       10,957       14,879       21,016       21,164
    Income before extraordinary
      charge..........................  $   0.55   $     0.67   $     1.26   $     1.65   $     2.19
    Extraordinary charge..............  $     --   $       --   $       --   $       --   $    (0.03)
    Net income........................  $   0.55   $     0.67   $     1.26   $     1.65   $     2.16
 
OTHER FINANCIAL DATA AND RATIOS:
  Depreciation and amortization.......  $ 21,580   $   26,896   $   40,551   $   48,935   $   82,913
  EBITDA(1)...........................  $ 53,707   $   69,515   $  117,379   $  172,616   $  255,306
  EBITDA to Consolidated Interest
    Expense(2)........................     2.23x        2.11x        2.41x        2.60x        2.74x
  Total debt to EBITDA................     6.23x        5.87x        5.12x        4.96x        4.20x
  Ratio of earnings to fixed
    charges(3)........................     1.52x        1.46x        1.45x        1.64x        1.68x
 
SELECTED OPERATING INFORMATION:
  Power plants:
    Electricity revenue(4):
      Energy..........................  $ 45,912   $   54,886   $   93,851   $  110,879   $  252,178
      Capacity........................  $  7,967   $   30,485   $   65,064   $   84,296   $  193,535
    Megawatt hours produced...........   447,177    1,033,566    1,985,404    2,158,008    9,864,080
    Average energy price per kilowatt
      hour(5).........................   10.267c       5.310c       4.727c       5.138c       2.557c
</TABLE>
 
Footnotes appear on the next page.
                                        5
<PAGE>   11
 
<TABLE>
<CAPTION>
                                                             AS OF DECEMBER 31,
                                        ------------------------------------------------------------
                                          1994        1995         1996         1997         1998
                                        --------   ----------   ----------   ----------   ----------
                                                           (DOLLARS IN THOUSANDS)
<S>                                     <C>        <C>          <C>          <C>          <C>
BALANCE SHEET DATA:
  Cash and cash equivalents...........  $ 22,527   $   21,810   $   95,970   $   48,513   $   96,532
  Total assets........................   421,372      554,531    1,031,397    1,380,915    1,728,946
  Short-term debt.....................    27,300       85,885       37,492      112,966        5,450
  Long-term line of credit............        --       19,851           --           --           --
  Long-term non-recourse debt.........   196,806      190,642      278,640      182,893      114,190
  Notes payable.......................     5,296        6,348           --           --           --
  Senior notes........................   105,000      105,000      285,000      560,000      951,750
  Total debt..........................   334,402      407,726      601,132      855,859    1,071,390
  Stockholders' equity................    18,649       25,227      203,127      239,956      286,966
</TABLE>
 
- ---------------
 
(1) EBITDA is defined as income from operations plus depreciation, capitalized
    interest, other income, non-cash charges and cash received from investments
    in power projects, reduced by the income from unconsolidated investments in
    power projects. EBITDA is presented not as a measure of operating results
    but rather as a measure of our ability to service debt. EBITDA should not be
    construed as an alternative either (a) to income from operations (determined
    in accordance with generally accepted accounting principles) or (b) to cash
    flows from operating activities (determined in accordance with generally
    accepted accounting principles).
 
(2) For purposes of calculating the EBITDA to Consolidated Interest Expense
    ratio, Consolidated Interest Expense is defined as total interest expense
    plus one-third of all operating lease obligations, dividends paid in respect
    of preferred stock and cash contributions to any employee stock ownership
    plan used to pay interest on loans incurred to purchase our capital stock.
 
(3) Earnings are defined as income before provision for taxes, extraordinary
    item and cumulative effect of changes in accounting principle plus cash
    received from investments in power projects and fixed charges reduced by the
    equity in income from investments in power projects and capitalized
    interest. Fixed charges consist of interest expense, capitalized interest,
    amortization of debt issuance costs and the portion of rental expenses
    representative of the interest expense component.
 
(4) Electricity revenue is comprised of fixed capacity payments, which are not
    related to production, and variable energy payments, which are related to
    production.
 
(5) Represents energy revenue divided by the megawatt hours produced.
                                        6
<PAGE>   12
 
                                  RISK FACTORS
 
     You should carefully consider the risks described below before making an
investment decision. The risks and uncertainties described below are not the
only ones facing our company. Additional risks and uncertainties not presently
known to us or that we currently deem immaterial may also impair our business
operations.
 
     Each of the following factors could have a material adverse effect on our
business, financial condition or results of operations, causing the trading
price of our common stock to decline and the loss of all or part of your
investment.
 
WE HAVE SUBSTANTIAL INDEBTEDNESS THAT WE MAY BE UNABLE TO SERVICE AND THAT
RESTRICTS OUR ACTIVITIES
 
     We have substantial debt that we incurred to finance the acquisition and
development of power generation facilities. As of December 31, 1998, our total
consolidated indebtedness was $1.1 billion, our total consolidated assets were
$1.7 billion and our stockholders' equity was $287.0 million. On December 31,
1998, on a pro forma basis after giving effect to the sale of $500.0 million of
the senior notes in the senior notes offering and the sale of common stock in
this offering, our total consolidated indebtedness would have been approximately
$1.5 billion, our total consolidated assets would have been approximately $2.3
billion and our pro forma cash balances would have been approximately $640
million. Whether we will be able to meet our debt service obligations and to
repay our outstanding indebtedness will be dependent primarily upon the
performance of our power generation facilities.
 
     This high level of indebtedness has important consequences, including:
 
     - limiting our ability to borrow additional amounts for working capital,
       capital expenditures, debt service requirements, execution of our growth
       strategy, or other purposes,
 
     - limiting our ability to use operating cash flow in other areas of our
       business because we must dedicate a substantial portion of these funds to
       service the debt,
 
     - increasing our vulnerability to general adverse economic and industry
       conditions, and
 
     - limiting our ability to capitalize on business opportunities and to react
       to competitive pressures and adverse changes in government regulation.
 
     The operating and financial restrictions and covenants in our existing debt
agreements, including the indentures relating to our outstanding senior notes
and our $100.0 million revolving credit facility, contain restrictive covenants.
Among other things, these restrictions limit or prohibit our ability to:
 
     - incur indebtedness,
 
     - make prepayments of indebtedness in whole or in part,
 
     - pay dividends,
 
     - make investments,
 
     - engage in transactions with affiliates,
 
                                        7
<PAGE>   13
 
     - create liens,
 
     - sell assets, and
 
     - acquire facilities or other businesses.
 
     Also, if our management or ownership changes, our indentures may require us
to make an offer to purchase our outstanding notes, including the senior notes.
We cannot assure you that we will have the financial resources necessary to
purchase such notes, and our board of directors cannot waive provisions in the
indentures. See "Description of the Senior Notes."
 
     We believe that our cash flow from operations, together with other
available sources of funds, including borrowings under our existing borrowing
arrangements, will be adequate to pay principal and interest on our debt and to
enable us to comply with the terms of our debt agreements. If we are unable to
comply with the terms of our debt agreements and fail to generate sufficient
cash flow from operations in the future, we may be required to refinance all or
a portion of our existing debt or to obtain additional financing. However, we
may be unable to refinance or obtain additional financing because of our high
levels of debt and the debt incurrence restrictions under our debt agreements.
If cash flow is insufficient and refinancing or additional financing is
unavailable, we may be forced to default on our debt obligations. In the event
of a default under the terms of any of our indebtedness, the debt holders may
accelerate the maturity of our obligations, which could cause defaults under our
other obligations.
 
OUR ABILITY TO REPAY OUR DEBT DEPENDS UPON THE PERFORMANCE OF OUR SUBSIDIARIES
 
     Almost all of our operations are conducted through our subsidiaries and
other affiliates. As a result, we depend almost entirely upon their earnings and
cash flow to service our indebtedness, including our ability to pay the interest
on and principal of our senior notes. The non-recourse project financing
agreements of certain of our subsidiaries and other affiliates generally
restrict their ability to pay dividends, make distributions or otherwise
transfer funds to us prior to the payment of other obligations, including
operating expenses, debt service and reserves.
 
     Our subsidiaries and other affiliates are separate and distinct legal
entities and have no obligation to pay any amounts due on our senior notes, and
do not guarantee the payment of interest on or principal of these notes. The
right of our senior note holders to receive any assets of any of our
subsidiaries or other affiliates upon our liquidation or reorganization will be
subordinated to the claims of any subsidiaries' or other affiliates' creditors
(including trade creditors and holders of debt issued by our subsidiaries or
affiliates). After giving pro forma effect to the sale of $500.0 million of the
senior notes in the senior notes offering, the sale of common stock in this
offering and the application of the proceeds from the offerings, as of December
31, 1998, none of our subsidiaries would have any non-recourse project financing
that would be effectively senior to our senior notes. However, we intend to
utilize non-recourse project financing in the future.
 
     While the indentures impose limitations on our ability and the ability of
our subsidiaries to incur additional indebtedness, the indentures do not limit
the amount of non-recourse project financing that our subsidiaries may incur to
finance new power generation facilities. See "Description of the
Notes -- Covenants -- Limitation on Incurrence of Indebtedness."
 
                                        8
<PAGE>   14
 
WE MAY BE UNABLE TO SECURE ADDITIONAL FINANCING IN THE FUTURE
 
     Each power generation facility that we acquire or develop will require
substantial capital investment. Our ability to arrange financing and the cost of
the financing are dependent upon numerous factors. These factors include:
 
     - general economic and capital market conditions,
 
     - conditions in energy markets,
 
     - regulatory developments,
 
     - credit availability from banks or other lenders,
 
     - investor confidence in the industry and in us,
 
     - the continued success of our current power generation facilities, and
 
     - provisions of tax and securities laws that are conducive to raising
       capital.
 
     Financing for new facilities may not be available to us on acceptable terms
in the future.
 
     We have financed our existing power generation facilities using a variety
of leveraged financing structures, primarily consisting of non-recourse project
financing and lease obligations. As of December 31, 1998, we had approximately
$1.1 billion of total consolidated indebtedness, of which approximately 11%
represented non-recourse project financing. After giving effect to the sale of
$500.0 million of senior notes and the application of the proceeds received from
the sale, as of December 31, 1998, we would have had approximately $1.5 billion
of total consolidated indebtedness, none of which would represent non-recourse
project financing. Each non-recourse project financing and lease obligation is
structured to be fully paid out of cash flow provided by the facility or
facilities. In the event of a default under a financing agreement which we do
not cure, the lenders or lessors would generally have rights to the facility and
any related assets. In the event of foreclosure after a default, we might not
retain any interest in the facility. While we intend to utilize non-recourse or
lease financing when appropriate, market conditions and other factors may
prevent similar financing for future facilities. We do not believe the existence
of non-recourse or lease financing will significantly affect our ability to
continue to borrow funds in the future in order to finance new facilities.
However, it is possible that we may be unable to obtain the financing required
to develop our power generation facilities on terms satisfactory to us.
 
     We have from time to time guaranteed certain obligations of our
subsidiaries and other affiliates. Our lenders or lessors may also require us to
guarantee the indebtedness for future facilities. This would render our general
corporate funds vulnerable in the event of a default by the facility or related
subsidiary. Additionally, our indentures may restrict our ability to guarantee
future debt, which could adversely affect our ability to fund new facilities.
Our indentures do not limit the ability of our subsidiaries to incur
non-recourse or lease financing for investment in new facilities.
 
                                        9
<PAGE>   15
 
REVENUE UNDER SOME OF OUR POWER SALES AGREEMENTS MAY BE REDUCED SIGNIFICANTLY
UPON THEIR EXPIRATION OR TERMINATION
 
     Most of the electricity we generate from our existing portfolio is sold
under long-term power sales agreements that expire at various times. When the
terms of each of these power sales agreements expire, it is possible that the
price paid to us for the generation of electricity may be reduced significantly,
which would greatly reduce our revenue under such agreements. The fixed price
periods in some of our long-term power sales agreements have recently expired,
and the electricity under those agreements is now sold at a fluctuating market
price. For example, the price for electricity for two of our power plants, the
Bear Canyon (20 megawatts) and West Ford Flat (27 megawatts) power plants, was
approximately 13.83 cents per kilowatt hour under the fixed price periods that
recently expired for these facilities, and is now set at the energy clearing
price, which averaged 2.66 cents per kilowatt hour during 1998. As a result, our
energy revenue under these power sales agreements has been materially reduced.
This reduction may lower our results of operations. We expect the forecasted
decline in energy revenues will be partially mitigated by decreased royalties
and planned operating cost reductions at these facilities. In addition, we will
continue our strategy of offsetting these reductions through our acquisition and
development program.
 
OUR POWER PROJECT DEVELOPMENT AND ACQUISITION ACTIVITIES MAY NOT BE SUCCESSFUL
 
     The development of power generation facilities is subject to substantial
risks. In connection with the development of a power generation facility, we
must generally obtain:
 
     - necessary power generation equipment,
 
     - governmental permits and approvals,
 
     - fuel supply and transportation agreements,
 
     - sufficient equity capital and debt financing,
 
     - electrical transmission agreements, and
 
     - site agreements and construction contracts.
 
We may be unsuccessful in accomplishing any of these matters or in doing so on a
timely basis. In addition, project development is subject to various
environmental, engineering and construction risks relating to cost-overruns,
delays and performance. Although we may attempt to minimize the financial risks
in the development of a project by securing a favorable power sales agreement,
obtaining all required governmental permits and approvals and arranging adequate
financing prior to the commencement of construction, the development of a power
project may require us to expend significant sums for preliminary engineering,
permitting and legal and other expenses before we can determine whether a
project is feasible, economically attractive or financeable. If we were unable
to complete the development of a facility, we would generally not be able to
recover our investment in the project. The process for obtaining initial
environmental, siting and other governmental permits and approvals is
complicated and lengthy, often taking more than one year, and is subject to
significant uncertainties. We cannot assure you that we will be successful in
the development of power generation facilities in the future.
 
                                       10
<PAGE>   16
 
     We have grown substantially in recent years as a result of acquisitions of
interests in power generation facilities and steam fields. We believe that
although the domestic power industry is undergoing consolidation and that
significant acquisition opportunities are available, we are likely to confront
significant competition for acquisition opportunities. In addition, we may be
unable to continue to identify attractive acquisition opportunities at favorable
prices or, to the extent that any opportunities are identified, we may be unable
to complete the acquisitions.
 
OUR PROJECTS UNDER CONSTRUCTION MAY NOT COMMENCE OPERATION AS SCHEDULED
 
     The commencement of operation of a newly constructed power generation
facility involves many risks, including:
 
     - start-up problems,
 
     - the breakdown or failure of equipment or processes, and
 
     - performance below expected levels of output or efficiency.
 
     New plants have no operating history and may employ recently developed and
technologically complex equipment. Insurance is maintained to protect against
certain risks, warranties are generally obtained for limited periods relating to
the construction of each project and its equipment in varying degrees, and
contractors and equipment suppliers are obligated to meet certain performance
levels. The insurance, warranties or performance guarantees, however, may not be
adequate to cover lost revenues or increased expenses. As a result, a project
may be unable to fund principal and interest payments under its financing
obligations and may operate at a loss. A default under such a financing
obligation could result in losing our interest in a power generation facility.
 
     In addition, power sales agreements entered into with a utility early in
the development phase of a project may enable the utility to terminate the
agreement, or to retain security posted as liquidated damages, if a project
fails to achieve commercial operation or certain operating levels by specified
dates or fails to make specified payments. In the event a termination right is
exercised the default provisions in a financing agreement may be triggered
(rendering such debt immediately due and payable). As a result, the project may
be rendered insolvent and we may lose our interest in the project.
 
OUR POWER GENERATION FACILITIES MAY NOT OPERATE AS PLANNED
 
     Upon completion of our pending acquisitions and projects currently under
construction, we will operate 31 of the 40 power plants in which we will have an
interest. The continued operation of power generation facilities involves many
risks, including the breakdown or failure of power generation equipment,
transmission lines, pipelines or other equipment or processes and performance
below expected levels of output or efficiency. Although from time to time our
power generation facilities have experienced equipment breakdowns or failures,
these breakdowns or failures have not had a significant effect on the operation
of the facilities or on our results of operations. As of December 31, 1998, our
power generation facilities have operated at an average availability of
approximately 96.5%. Although our facilities contain various redundancies and
back-up mechanisms, a breakdown or failure may prevent the affected facility
from performing under applicable power sales agreements. In addition, although
insurance is maintained to protect against operating risks, the proceeds of
insurance may not be adequate to cover lost revenues or
 
                                       11
<PAGE>   17
 
increased expenses. As a result, we could be unable to service principal and
interest payments under our financing obligations which could result in losing
our interest in the power generation facility.
 
OUR GEOTHERMAL ENERGY RESERVES MAY BE INADEQUATE FOR OUR OPERATIONS
 
     The development and operation of geothermal energy resources are subject to
substantial risks and uncertainties similar to those experienced in the
development of oil and gas resources. The successful exploitation of a
geothermal energy resource ultimately depends upon:
 
     - the heat content of the extractable fluids,
 
     - the geology of the reservoir,
 
     - the total amount of recoverable reserves,
 
     - operating expenses relating to the extraction of fluids,
 
     - price levels relating to the extraction of fluids, and
 
     - capital expenditure requirements relating primarily to the drilling of
       new wells.
 
     In connection with each geothermal power plant, we estimate the
productivity of the geothermal resource and the expected decline in
productivity. The productivity of a geothermal resource may decline more than
anticipated, resulting in insufficient reserves being available for sustained
generation of the electrical power capacity desired. An incorrect estimate by us
or an unexpected decline in productivity could lower our results of operations.
 
     Geothermal reservoirs are highly complex. As a result, there exist numerous
uncertainties in determining the extent of the reservoirs and the quantity and
productivity of the steam reserves. Reservoir engineering is an inexact process
of estimating underground accumulations of steam or fluids that cannot be
measured in any precise way, and depends significantly on the quantity and
accuracy of available data. As a result, the estimates of other reservoir
specialists may differ materially from ours. Estimates of reserves are generally
revised over time on the basis of the results of drilling, testing and
production that occur after the original estimate was prepared. While we have
extensive experience in the operation and development of geothermal energy
resources and in preparing such estimates, we cannot assure you that we will be
able to successfully manage the development and operation of our geothermal
reservoirs or that we will accurately estimate the quantity or productivity of
our steam reserves.
 
WE DEPEND ON OUR ELECTRICITY AND THERMAL ENERGY CUSTOMERS
 
     Each of our power generation facilities currently relies on one or more
power sales agreements with one or more utility or other customers for all or
substantially all of such facility's revenue. In addition, the sales of
electricity to two utility customers during 1998 comprised approximately 64% of
our total revenue during that year. The loss of any one power sales agreement
with any of these customers could have a negative effect on our results of
operations. In addition, any material failure by any customer to fulfill its
obligations under a power sales agreement could have a negative effect on the
cash flow available to us and on our results of operations.
 
                                       12
<PAGE>   18
 
WE ARE SUBJECT TO COMPLEX GOVERNMENT REGULATION WHICH COULD ADVERSELY AFFECT OUR
OPERATIONS
 
     Our activities are subject to complex and stringent energy, environmental
and other governmental laws and regulations. The construction and operation of
power generation facilities require numerous permits, approvals and certificates
from appropriate federal, state and local governmental agencies, as well as
compliance with environmental protection legislation and other regulations.
While we believe that we have obtained the requisite approvals for our existing
operations and that our business is operated in accordance with applicable laws,
we remain subject to a varied and complex body of laws and regulations that both
public officials and private individuals may seek to enforce. Existing laws and
regulations may be revised or new laws and regulations may become applicable to
us that may have a negative effect on our business and results of operations. We
may be unable to obtain all necessary licenses, permits, approvals and
certificates for proposed projects, and completed facilities may not comply with
all applicable permit conditions, statutes or regulations. In addition,
regulatory compliance for the construction of new facilities is a costly and
time-consuming process. Intricate and changing environmental and other
regulatory requirements may necessitate substantial expenditures to obtain
permits. If a project is unable to function as planned due to changing
requirements or local opposition, it may create expensive delays or significant
loss of value in a project.
 
     Our operations are potentially subject to the provisions of various energy
laws and regulations, including the Public Utility Regulatory Policies Act of
1978, as amended ("PURPA"), the Public Utility Holding Company Act of 1955, as
amended ("PUHCA"), and state and local regulations. PUHCA provides for the
extensive regulation of public utility holding companies and their subsidiaries.
PURPA provides to qualifying facilities ("QFs") (as defined under PURPA) and
owners of QFs certain exemptions from certain federal and state regulations,
including rate and financial regulations.
 
     Under present federal law, we are not subject to regulation as a holding
company under PUHCA, and will not be subject to such regulation as long as the
plants in which we have an interest (1) qualify as QFs, (2) are subject to
another exemption or waiver or (3) qualify as exempt wholesale generators
("EWG") under the Energy Policy Act of 1992. In order to be a QF, a facility
must be not more than 50% owned by an electric utility company or electric
utility holding company. In addition, a QF that is a cogeneration facility, such
as the plants in which we currently have interests, must produce electricity as
well as thermal energy for use in an industrial or commercial process in
specified minimum proportions. The QF also must meet certain minimum energy
efficiency standards. Any geothermal power facility which produces up to 80
megawatts of electricity and meets PURPA ownership requirements is considered a
QF.
 
     If any of the plants in which we have an interest lose their QF status or
if amendments to PURPA are enacted that substantially reduce the benefits
currently afforded QFs, we could become a public utility holding company, which
could subject us to significant federal, state and local regulation, including
rate regulation. If we become a holding company, which could be deemed to occur
prospectively or retroactively to the date that any of our plants loses its QF
status, all our other power plants could lose QF status because, under FERC
regulations, a QF cannot be owned by an electric utility or electric utility
holding company. In addition, a loss of QF status could, depending on the
particular power purchase agreement, allow the power purchaser to cease taking
and paying for electricity or to seek refunds of past amounts paid and thus
could cause the loss
 
                                       13
<PAGE>   19
 
of some or all contract revenues or otherwise impair the value of a project. If
a power purchaser were to cease taking and paying for electricity or seek to
obtain refunds of past amounts paid, there can be no assurance that the costs
incurred in connection with the project could be recovered through sales to
other purchasers. Such events could adversely affect our ability to service our
indebtedness, including our senior notes. See "Business -- Government
Regulation -- Federal Energy Regulation."
 
     Currently, Congress is considering proposed legislation that would amend
PURPA by eliminating the requirement that utilities purchase electricity from
QFs at prices based on avoided costs of energy. We do not know whether this
legislation will be passed or, if passed, what form it may take. We cannot
assure that any legislation passed would not adversely impact our existing
domestic projects.
 
     In addition, many states are implementing or considering regulatory
initiatives designed to increase competition in the domestic power generation
industry and increase access to electric utilities' transmission and
distribution systems for independent power producers and electricity consumers.
In particular, the state of California has restructured its electric industry by
providing for a phased-in competitive power generation industry, with a power
pool and an independent system operator, and for direct access to generation for
all power purchasers outside the power exchange under certain circumstances.
Although existing QF power sales contracts are to be honored under such
restructuring, and all of our California operating projects are QFs, until the
new system is fully implemented, it is impossible to predict what impact, if
any, it may have on the operations of those projects.
 
WE MAY BE UNABLE TO OBTAIN AN ADEQUATE SUPPLY OF NATURAL GAS IN THE FUTURE
 
     To date, our fuel acquisition strategy has included various combinations of
our own gas reserves, gas prepayment contracts and short-, medium- and long-term
supply contracts. In our gas supply arrangements, we attempt to match the fuel
cost with the fuel component included in the facility's power sales agreements,
in order to minimize a project's exposure to fuel price risk. We believe that
there will be adequate supplies of natural gas available at reasonable prices
for each of our facilities when current gas supply agreements expire. However,
gas supplies may not be available for the full term of the facilities' power
sales agreements, and gas prices may increase significantly. If gas is not
available, or if gas prices increase above the fuel component of the facilities'
power sales agreements, there could be a negative impact on our results of
operations.
 
COMPETITION COULD ADVERSELY AFFECT OUR PERFORMANCE
 
     The power generation industry is characterized by intense competition. We
encounter competition from utilities, industrial companies and other power
producers. In recent years, there has been increasing competition in an effort
to obtain power sales agreements. This competition has contributed to a
reduction in electricity prices. In addition, many states have implemented or
are considering regulatory initiatives designed to increase competition in the
domestic power industry. This competition has put pressure on electric utilities
to lower their costs, including the cost of purchased electricity.
 
                                       14
<PAGE>   20
 
OUR INTERNATIONAL INVESTMENTS MAY FACE UNCERTAINTIES
 
     We have one investment in geothermal steam fields located in Mexico and may
pursue additional international investments. International investments are
subject to unique risks and uncertainties relating to the political, social and
economic structures of the countries in which we invest. Risks specifically
related to investments in non-United States projects may include:
 
     - risks of fluctuations in currency valuation,
 
     - currency inconvertibility,
 
     - expropriation and confiscatory taxation,
 
     - increased regulation, and
 
     - approval requirements and governmental policies limiting returns to
       foreign investors.
 
WE DEPEND ON OUR SENIOR MANAGEMENT
 
     Our success is largely dependent on the skills, experience and efforts of
our senior management. The loss of the services of one or more members of our
senior management could have a negative effect on our business and development.
 
SEISMIC DISTURBANCES COULD DAMAGE OUR PROJECTS
 
     Areas where we operate and are developing many of our geothermal and
gas-fired projects are subject to frequent low-level seismic disturbances. More
significant seismic disturbances are possible. Our existing power generation
facilities are built to withstand relatively significant levels of seismic
disturbances, and we believe we maintain adequate insurance protection. However,
earthquake, property damage or business interruption insurance may be inadequate
to cover all potential losses sustained in the event of serious seismic
disturbances. Additionally, insurance may not continue to be available to us on
commercially reasonable terms.
 
OUR RESULTS ARE SUBJECT TO QUARTERLY AND SEASONAL FLUCTUATIONS
 
     Our quarterly operating results have fluctuated in the past and may
continue to do so in the future as a result of a number of factors, including:
 
     - the timing and size of acquisitions,
 
     - the completion of development projects, and
 
     - variations in levels of production.
 
     Additionally, because we receive the majority of capacity payments under
some of our power sales agreements during the months of May through October, our
revenues and results of operations are, to some extent, seasonal.
 
THE PRICE OF OUR COMMON STOCK IS VOLATILE
 
     The market price for our common stock has been volatile in the past, and
several factors could cause the price to fluctuate substantially in the future.
These factors include:
 
     - announcements of developments related to our business,
 
     - fluctuations in our results of operations,
 
     - sales of substantial amounts of our securities into the marketplace,
 
                                       15
<PAGE>   21
 
     - general conditions in our industry or the worldwide economy,
 
     - an outbreak of war or hostilities,
 
     - a shortfall in revenues or earnings compared to securities analysts'
       expectations,
 
     - changes in analysts' recommendations or projections, and
 
     - announcements of new acquisitions or development projects by us.
 
     The market price of our common stock may fluctuate significantly in the
future, and these fluctuations may be unrelated to our performance. General
market price declines or market volatility in the future could adversely affect
the price of our common stock, and thus, the current market price may not be
indicative of future market prices.
 
WE COULD BE ADVERSELY AFFECTED IF OUR COMPUTER SYSTEMS ARE NOT YEAR 2000
COMPLIANT
 
     The "Year 2000 problem" refers to the fact that some computer hardware,
software and embedded systems were designed to read and store dates using only
the last two digits of the year.
 
     We are coordinating our efforts to address the impact of Year 2000 on our
business through an analysis of four separate technology domains:
 
     - corporate applications, which include core business systems,
 
     - non-information technology, which includes all operating and control
       systems,
 
     - end-user computing systems (that is, systems that are not considered core
       business systems but may contain date calculations), and
 
     - business partner and vendor systems.
 
     We currently expect to complete our Year 2000 efforts with respect to
critical systems by mid-1999. This schedule and our cost estimates may be
affected by, among other things, the availability of Year 2000 personnel, the
readiness of third parties, the timing for testing our embedded systems, the
availability of vendor resources to complete embedded system assessments and
produce required component upgrades and our ability to implement appropriate
contingency plans.
 
     We produce revenues by selling power we produce to customers. We depend on
transmission and distribution facilities that are owned and operated by
investor-owned utilities to deliver power to our customers. If either our
customers or the providers of transmission and distribution facilities
experience significant disruptions as a result of the Year 2000 problem, our
ability to sell and deliver power may be hindered, which could result in a loss
of revenue.
 
     The cost or consequences of a materially incomplete or untimely resolution
of the Year 2000 problem could adversely affect our future operations, financial
results or our financial condition.
 
                      WHERE YOU CAN FIND MORE INFORMATION
 
     We file annual, quarterly and special reports, proxy statements and other
information with the Securities and Exchange Commission (the "SEC"). You may
read and copy any document we file at the public reference facilities of the SEC
located at 450 Fifth Street N.W., Washington D.C. 20549. You may obtain
information on the operation of the SEC's public reference facilities by calling
the SEC at 1-800-SEC-0330. You can also access copies
 
                                       16
<PAGE>   22
 
of such material electronically on the SEC's home page on the World Wide Web at
http://www.sec.gov.
 
     This prospectus is part of a registration statement (Registration No.
333-          ) we filed with the SEC. The SEC permits us to "incorporate by
reference" the information we file with them, which means that we can disclose
important information to you by referring you to those documents. The
information incorporated by reference is considered to be part of this
prospectus, and information that we file with the SEC after the date of this
prospectus will automatically update and supersede this information. We
incorporate by reference our Annual Report on Form 10-K for the year ended
December 31, 1998, as amended, filed by us with the SEC. We also incorporate by
reference any future filings made with the SEC under Sections 13(a), 13(c), 14
or 15(d) of the Securities Exchange Act of 1934, as amended, until we sell all
of the shares of common stock and senior notes being registered or until this
offering is otherwise terminated.
 
     If you request a copy of any or all of the documents incorporated by
reference, then we will send to you the copies you requested at no charge.
However, we will not send exhibits to such documents, unless such exhibits are
specifically incorporated by reference in such documents. You should direct
requests for such copies to Investor Relations, Calpine Corporation, 50 West San
Fernando Street, San Jose, California 95113. Our telephone number is (408)
995-5115.
 
                           FORWARD-LOOKING STATEMENTS
 
     Some of the statements in this prospectus and incorporated by reference are
forward-looking statements. These statements involve known and unknown risks,
uncertainties, and other factors that may cause our or our industry's actual
results, levels of activity, performance, or achievements to be materially
different from any future results, levels of activity, performance, or
achievements expressed or implied by such forward-looking statements. Such
factors include, among other things, those listed under "Risk Factors" and
elsewhere in this prospectus.
 
     In some cases, you can identify forward-looking statements by terminology
such as "may," "will," "should," "expects," "plans," "anticipates," "believes,"
"estimates," "predicts," "potential," or "continue" or the negative of such
terms or other comparable terminology.
 
     Although we believe that the expectations reflected in the forward-looking
statements are reasonable, we cannot guarantee future results, levels of
activity, performance, or achievements. Moreover, neither we nor any other
person assumes responsibility for the accuracy and completeness of such
statements. We are under no duty to update any of the forward-looking statements
after the date of this prospectus to conform such statements to actual results.
 
                                       17
<PAGE>   23
 
                                USE OF PROCEEDS
 
     The aggregate net proceeds to us from the sale of the 6,000,000 shares of
common stock offered by us in the common stock offering and $500.0 million of
senior notes in the senior note offering (after deducting underwriting discounts
and commissions and estimated offering expenses) will be approximately $
million ($  million if the underwriters' over-allotment option in the common
stock offering is exercised in full). We expect to utilize a portion of the net
proceeds from the offerings as follows: (1) $119.6 million to refinance
indebtedness relating to the Gilroy Power Plant, (2) $101.0 million to acquire
the steam fields that service the Sonoma County Power Plants, (3) $25.0 million
to complete the expansion of the Clear Lake Power Plant and (4) approximately
$400.0 million to finance a portion of the power generation facilities currently
under construction and the projects currently under development, including, but
not limited to, the Westbrook, Sutter, South Point and Magic Valley power
plants. The outstanding balance on the Gilroy Power Plant debt is approximately
$119.6 million as of the date of this prospectus and bears interest at 6.8% per
annum and matures in August 2014. The remaining net proceeds, if any, will be
used for working capital and general corporate purposes, and for the development
and acquisition of additional power generation facilities. See
"Business -- Project Development and Acquisitions." Pending such uses, we expect
to invest the net proceeds in short-term, interest-bearing securities.
 
                                       18
<PAGE>   24
 
                          PRICE RANGE OF COMMON STOCK
 
     Our common stock is traded on the New York Stock Exchange under the symbol
"CPN." Public trading of the common stock commenced on September 20, 1996. Prior
to that, there was no public market for the common stock. The following table
sets forth, for the periods indicated, the high and low sale price per share of
the common stock on the New York Stock Exchange.
 
<TABLE>
<CAPTION>
                                                              HIGH        LOW
                                                             -------    -------
<S>                                                          <C>        <C>
1997
First Quarter..............................................  $22.750    $17.125
Second Quarter.............................................   20.875     15.750
Third Quarter..............................................   22.938     16.500
Fourth Quarter.............................................   21.250     12.375
 
1998
First Quarter..............................................  $18.500    $12.750
Second Quarter.............................................   21.250     17.250
Third Quarter..............................................   21.500     17.125
Fourth Quarter.............................................   27.625     17.813
 
1999
First Quarter (through              , 1999)................  $          $
</TABLE>
 
     As of              , 1999, there were approximately      holders of record
of our common stock. On              , 1999, the last sale price reported on the
New York Stock Exchange for our common stock was $     per share.
 
                                DIVIDEND POLICY
 
     We do not anticipate paying any cash dividends on our common stock in the
foreseeable future because we intend to retain our earnings to finance the
expansion of our business and for general corporate purposes. In addition, our
ability to pay cash dividends is restricted under our indentures and our other
debt agreements. Future cash dividends, if any, will be at the discretion of our
board of directors and will depend upon, among other things, our future
operations and earnings, capital requirements, general financial condition,
contractual restrictions and such other factors as the board of directors may
deem relevant.
 
                                       19
<PAGE>   25
 
                                 CAPITALIZATION
 
     The following table sets forth, as of December 31, 1998 (1) the actual
consolidated capitalization of the Company; and (2) the consolidated
capitalization of our Company as adjusted for the sale of senior notes, the sale
of the shares of our common stock in this offering (at an assumed offering price
of $      per share) and the application of the estimated net proceeds therefrom
as described in "Use of Proceeds." This table should be read in conjunction with
the consolidated financial statements and related notes thereto incorporated by
reference in this prospectus.
 
<TABLE>
<CAPTION>
                                                           DECEMBER 31, 1998
                                                       -------------------------
                                                         ACTUAL      AS ADJUSTED
                                                       ----------    -----------
                                                        (DOLLARS IN THOUSANDS,
                                                       EXCEPT PER SHARE AMOUNTS)
<S>                                                    <C>           <C>
CASH:
  Cash and cash equivalents..........................  $   96,532    $
                                                       ==========    ===========
 
SHORT-TERM DEBT:
  Current portion of non-recourse project
     financing.......................................  $    5,450    $        --
  Notes payable and short-term borrowings............          --             --
                                                       ----------    -----------
          Total short-term debt......................  $    5,450    $        --
                                                       ==========    ===========
 
LONG-TERM DEBT:
  Non-recourse project financing, net of current
     portion.........................................     114,190             --
  Senior notes.......................................     951,750      1,451,750
                                                       ----------    -----------
          Total long-term debt.......................   1,065,940      1,451,750
                                                       ----------    -----------
 
STOCKHOLDERS' EQUITY:
  Preferred stock, $0.001 par value:
     10,000,000 shares authorized; no shares
     outstanding, actual and as adjusted.............          --             --
  Common stock, $0.001 par value:
     100,000,000 shares authorized; 20,161,581 shares
     outstanding, actual; and 26,161,581 shares
     outstanding, as adjusted(1).....................          20             26
  Additional paid-in capital.........................     168,874
  Retained earnings..................................     118,072        118,072
                                                       ----------    -----------
          Total stockholders' equity.................     286,966
                                                       ----------    -----------
             Total capitalization....................  $1,352,906    $
                                                       ==========    ===========
</TABLE>
 
- ---------------
(1) Does not include 2,884,440 shares of common stock subject to issuance upon
    exercise of options previously granted and outstanding as of December 31,
    1998, under our 1996 Stock Incentive Plan.
 
                                       20
<PAGE>   26
 
                      SELECTED CONSOLIDATED FINANCIAL DATA
 
     The consolidated financial data set forth below for the five years ended
and as of December 31, 1998 have been derived from the audited consolidated
financial statements of our company. The following selected consolidated
financial data should be read in conjunction with the consolidated financial
statements and the related notes thereto incorporated by reference in this
prospectus.
 
<TABLE>
<CAPTION>
                                                          YEAR ENDED DECEMBER 31,
                                         ----------------------------------------------------------
                                           1994       1995        1996         1997         1998
                                         --------   --------   ----------   ----------   ----------
                                                  (IN THOUSANDS, EXCEPT PER SHARE AMOUNTS)
<S>                                      <C>        <C>        <C>          <C>          <C>
STATEMENT OF OPERATIONS DATA:
Revenue:
  Electricity and steam sales..........  $ 90,295   $127,799   $  199,464   $  237,277   $  507,897
  Service contract revenue from related
    parties............................     7,221      7,153        6,455       10,177       20,249
  Income (loss) from unconsolidated
    investments in power projects......    (2,754)    (2,854)       6,537       15,819       25,240
  Interest income on loans to power
    projects...........................        --         --        2,098       13,048        2,562
                                         --------   --------   ----------   ----------   ----------
         Total revenue.................    94,762    132,098      214,554      276,321      555,948
Cost of revenue........................    52,845     77,388      129,200      153,308      375,327
                                         --------   --------   ----------   ----------   ----------
Gross profit...........................    41,917     54,710       85,354      123,013      180,621
Project development expenses...........     1,784      3,087        3,867        7,537        7,165
General and administrative expenses....     7,323      8,937       14,696       18,289       26,780
Provision for write-off of project
  development costs....................     1,038         --           --           --           --
                                         --------   --------   ----------   ----------   ----------
Income from operations.................    31,772     42,686       66,791       97,187      146,676
Interest expense.......................    23,886     32,154       45,294       61,466       86,726
Other (income) expense.................    (1,988)    (1,895)      (6,259)     (17,438)     (13,423)
                                         --------   --------   ----------   ----------   ----------
  Income before provision for income
    taxes..............................     9,874     12,427       27,756       53,159       73,373
Provision for income taxes.............     3,853      5,049        9,064       18,460       27,054
                                         --------   --------   ----------   ----------   ----------
  Income before extraordinary charge...     6,021      7,378       18,692       34,699       46,319
Extraordinary charge for retirement of
  debt, net of tax benefit of $441.....        --         --           --           --          641
                                         --------   --------   ----------   ----------   ----------
  Net income...........................  $  6,021   $  7,378   $   18,692   $   34,699   $   45,678
                                         ========   ========   ==========   ==========   ==========
Basic earnings per common share:
  Weighted average shares of common
    stock outstanding..................    10,388     10,388       12,903       19,946       20,121
  Income before extraordinary charge...  $   0.58   $   0.71   $     1.45   $     1.74   $     2.30
  Extraordinary charge.................  $     --   $     --   $       --   $       --   $    (0.03)
  Net income...........................  $   0.58   $   0.71   $     1.45   $     1.74   $     2.27
Diluted earnings per common share:
  Weighted average shares of common
    stock outstanding..................    10,921     10,957       14,879       21,016       21,164
  Income before extraordinary charge...  $   0.55   $   0.67   $     1.26   $     1.65   $     2.19
  Extraordinary charge.................  $     --   $     --   $       --   $       --   $    (0.03)
  Net income...........................  $   0.55   $   0.67   $     1.26   $     1.65   $     2.16
</TABLE>
 
                                       21
<PAGE>   27
 
<TABLE>
<CAPTION>
                                                          YEAR ENDED DECEMBER 31,
                                         ----------------------------------------------------------
                                           1994       1995        1996         1997         1998
                                         --------   --------   ----------   ----------   ----------
                                                       (IN THOUSANDS, EXCEPT RATIOS)
<S>                                      <C>        <C>        <C>          <C>          <C>
OTHER FINANCIAL DATA AND RATIOS:
Depreciation and amortization..........  $ 21,580   $ 26,896   $   40,551   $   48,935   $   82,913
EBITDA(1)..............................  $ 53,707   $ 69,515   $  117,379   $  172,616   $  255,306
EBITDA to Consolidated Interest
  Expense(2)...........................     2.23x      2.11x        2.41x        2.60x        2.74x
Total debt to EBITDA...................     6.23x      5.87x        5.12x        4.96x        4.20x
Ratio of earnings to fixed
  charges(3)...........................     1.52x      1.46x        1.45x        1.64x        1.68x
</TABLE>
 
<TABLE>
<CAPTION>
                                                             AS OF DECEMBER 31,
                                         ----------------------------------------------------------
                                           1994       1995        1996         1997         1998
                                         --------   --------   ----------   ----------   ----------
                                                               (IN THOUSANDS)
<S>                                      <C>        <C>        <C>          <C>          <C>
BALANCE SHEET DATA:
Cash and cash equivalents..............  $ 22,527   $ 21,810   $   95,970   $   48,513   $   96,532
Property, plant and equipment, net.....   335,453    447,751      648,208      736,339    1,094,303
Investments in power projects..........    11,114      8,218       13,936      222,542      221,509
Notes receivable.......................    16,882     25,785       36,143      117,357       10,899
Total assets...........................   421,372    554,531    1,031,397    1,380,915    1,728,946
Short-term debt........................    27,300     85,885       37,492      112,966        5,450
Long-term line of credit...............        --     19,851           --           --           --
Non-recourse debt......................   196,806    190,642      278,640      182,893      114,190
Notes payable..........................     5,296      6,348           --           --           --
Senior notes...........................   105,000    105,000      285,000      560,000      951,750
Total debt.............................   334,402    407,726      601,132      855,859    1,071,390
Stockholders' equity...................    18,649     25,227      203,127      239,956      286,966
</TABLE>
 
- ---------------
(1) EBITDA is defined as income from operations plus depreciation, capitalized
    interest, other income, non-cash charges and cash received from investments
    in power projects, reduced by the income from unconsolidated investments in
    power projects. EBITDA is presented here not as a measure of operating
    results but rather as a measure of our ability to service debt. EBITDA
    should not be construed as an alternative either (a) to income from
    operations (determined in accordance with generally accepted accounting
    principles) or (b) to cash flows from operating activities (determined in
    accordance with generally accepted accounting principles).
 
(2) For purposes of calculating the EBITDA to Consolidated Interest Expense
    ratio, Consolidated Interest Expense is defined as total interest expense
    plus one-third of all operating lease obligations, dividends paid in respect
    of preferred stock and cash contributions to any employee stock ownership
    plan used to pay interest on loans incurred to purchase our capital stock.
 
(3) Earnings are defined as income before provision for taxes, extraordinary
    item and cumulative effect of change in accounting principle plus cash
    received from investments in power projects and fixed charges reduced by the
    equity in income from investments in power projects and capitalized
    interest. Fixed charges consist of interest expense, capitalized interest,
    amortization of debt issuance costs and the portion of rental expenses
    representative of the interest expense component.
 
                                       22
<PAGE>   28
 
                     PRO FORMA CONSOLIDATED FINANCIAL DATA
 
     The following unaudited pro forma consolidated statement of operations for
the year ended December 31, 1998 gives effect to the following transactions as
if such transactions had occurred on January 1, 1998: (1) our acquisition of the
remaining 55% interest in the Bethpage Power Plant on February 5, 1998 (the
"Bethpage Transaction"); (2) our acquisition of the remaining 50% interest in
the Texas City Power Plant and the Clear Lake Power Plant on April 1, 1998 (the
"Texas City/Clear Lake Transaction"); (3) our sale of $300,000,000 of 7 7/8%
Senior Notes Due 2008 on March 31, 1998, and the application of the net proceeds
therefrom; and (4) our sale of $100,000,000 of 7 7/8% Senior Notes Due 2008 on
July 24, 1998 and the application of the net proceeds therefrom (the Bethpage
Transaction, the Texas City/Clear Lake Transaction, the sale of $300,000,000 of
7 7/8% Senior Notes Due 2008 and the sale of $100,000,000 of 7 7/8% Senior Notes
Due 2008 being collectively referred to as the "Transactions").
 
     The pro forma consolidated financial data and accompanying notes should be
read in conjunction with the consolidated financial statements and related notes
thereto incorporated by reference in this prospectus. The pro forma adjustments
are based upon available information and certain assumptions that management
believes are reasonable and are described in the notes accompanying the pro
forma consolidated financial data. The pro forma consolidated financial data are
presented for informational purposes only and do not purport to represent what
our results of operations would actually have been had such transactions in fact
occurred at such dates, or to project our results of operations for any future
period. In the opinion of management, all adjustments necessary to present
fairly such pro forma consolidated financial data have been made.
 
                                       23
<PAGE>   29
 
                 PRO FORMA CONSOLIDATED STATEMENT OF OPERATIONS
 
<TABLE>
<CAPTION>
                                                              YEAR ENDED DECEMBER 31, 1998
                                                    -------------------------------------------------
                                                                  ADJUSTMENTS          PRO FORMA
                                                                    FOR THE             FOR THE
                                                     ACTUAL       TRANSACTIONS        TRANSACTIONS
                                                    ---------   ----------------   ------------------
                                                    (IN THOUSANDS, EXCEPT RATIOS AND PER SHARE DATA)
<S>                                                 <C>         <C>                <C>
STATEMENT OF OPERATIONS DATA:
Revenue:
  Electricity and steam sales.....................  $507,897       $  74,163            $582,060
  Service contract revenue from related parties...    20,249          (1,613)             18,636
  Income from unconsolidated investments in power
    projects......................................    25,240          (1,765)             23,475
  Interest income on loans to power projects......     2,562          (2,520)                 42
                                                    --------       ---------            --------
         Total revenue............................   555,948          68,265             624,213
                                                    --------       ---------            --------
Cost of revenue:
  Plant operating expenses........................   256,079          48,764             304,843
  Depreciation....................................    73,988           7,612              81,600
  Production royalties............................    10,714              --              10,714
  Operating lease expenses........................    17,129          (1,277)             15,852
  Service contract expenses.......................    17,417              --              17,417
                                                    --------       ---------            --------
         Total cost of revenue....................   375,327          55,099             430,426
                                                    --------       ---------            --------
Gross profit......................................   180,621          13,166             193,787
Project development expenses......................     7,165              --               7,165
General and administrative expenses...............    26,780             (27)             26,753
                                                    --------       ---------            --------
  Income from operations..........................   146,676          13,193             159,869
Interest expense..................................    86,726           8,302              95,028
Interest income...................................   (12,348)             --             (12,348)
Other (income) expense............................    (1,075)           (146)             (1,221)
                                                    --------       ---------            --------
  Income before provision for income taxes........    73,373           5,037              78,410
Provision for income taxes........................    27,054           1,689              28,743
                                                    --------       ---------            --------
Income before extraordinary charge................    46,319           3,348              49,667
Extraordinary charge for retirement of debt, net
  of tax benefit of $441..........................       641              --                 641
                                                    --------       ---------            --------
    Net income....................................  $ 45,678       $   3,348            $ 49,026
                                                    ========       =========            ========
Basic earnings per common share:
  Weighted average shares of common stock
    outstanding...................................    20,121                              20,121
  Income before extraordinary charge..............  $   2.30                            $   2.47
  Extraordinary charge............................  $  (0.03)                           $  (0.03)
  Net income......................................  $   2.27                            $   2.44
Diluted earnings per common share:
  Weighted average shares of common stock
    outstanding...................................    21,164                              21,164
  Income before extraordinary charge..............  $   2.19                            $   2.35
  Extraordinary charge............................  $  (0.03)                           $  (0.03)
  Net income......................................  $   2.16                            $   2.32
OTHER OPERATING DATA AND RATIOS:
  Depreciation and amortization...................  $ 82,913                            $ 90,525
  EBITDA..........................................  $255,306                            $278,091
  EBITDA to Consolidated Interest Expense.........     2.74x                               2.74x
  Total debt to EBITDA............................     4.20x                               3.85x
  Ratio of earnings to fixed charges..............     1.68x                               1.69x
</TABLE>
 
                                       24
<PAGE>   30
 
                      MANAGEMENT'S DISCUSSION AND ANALYSIS
                OF FINANCIAL CONDITION AND RESULTS OF OPERATION
 
OVERVIEW
 
     Calpine is engaged in the development, acquisition, ownership and operation
of power generation facilities and the sale of electricity and steam principally
in the United States. At December 31, 1998, we had interests in 22 power plants
and three steam fields predominantly in the United States, having an aggregate
capacity of 3,018 megawatts.
 
     On February 5, 1998, we acquired the remaining 55% interest in, and assumed
operations and maintenance of, the Bethpage Power Plant. We purchased the
remaining interests for approximately $5.0 million. Additionally, on March 31,
1998 we repaid all outstanding project debt of $37.4 million related to the
Bethpage Power Plant.
 
     On March 31, 1998, we completed the acquisition of the remaining 50%
interest in the Texas Cogeneration Company ("TCC"), which is the owner of the
Texas City and Clear Lake Power Plants. We paid $52.8 million in cash and agreed
to make certain contingent purchase payments that could approximate 2.2% of
project revenue beginning in the year 2000, increasing to 2.9% in 2002. As part
of this acquisition, we own a 7.5% interest in the Bayonne Power Plant, a 165
megawatt gas-fired cogeneration power plant located in Bayonne, New Jersey. In
addition, we paid $105.3 million to restructure certain gas contracts related to
this acquisition.
 
     On July 13, 1998, we signed a letter of intent to enter into a joint
venture to develop, own and operate approximately 2,000 megawatts of gas-fired
power plants in northern California primarily to serve the San Francisco Bay
Area. The gas-fired plants are to be constructed by Bechtel and operated by us.
We have announced that the first plant to be developed under the joint venture
will be the Delta Energy Center, an 880 megawatt gas-fired plant located at the
Dow Chemical facility in Pittsburg, California.
 
     On July 17, 1998, we completed the purchase of a 60 megawatt geothermal
power plant located in Sonoma County, California, from the Sacramento Municipal
Utility District ("SMUD") for $13.0 million. We are the owner and operator of
the geothermal steam fields that provide steam to this facility. Under the
agreement, we paid SMUD $10.6 million at closing, and agreed to pay an
additional $2.4 million over the next two years. In connection with the
acquisition, SMUD agreed to purchase up to 50 megawatts of electricity from the
plant at current market prices plus a renewable power premium through 2001. In
addition, SMUD has the option to purchase 10 megawatts of off-peak power
production through 2005. We currently market the excess electricity into the
California power market.
 
     On July 21, 1998, we completed the acquisition of a 70 megawatt gas-fired
power plant from The Dow Chemical Company for approximately $13.1 million. The
power plant is located at Dow's Pittsburg, California chemical facility. We will
sell up to 18 megawatts of electricity to Dow under a ten-year power sales
agreement, with the balance sold to Pacific Gas & Electric Company ("PG&E")
under an existing power sales agreement. In addition, we will sell approximately
200,000 lbs./hr of steam to Dow and to USS-POSCO Industries' nearby steel mill.
 
                                       25
<PAGE>   31
 
     In August 1998, we entered into a sale and leaseback transaction for
certain plant and equipment of our Greenleaf 1 & 2 Power Plants, two 49.5
megawatt gas-fired cogeneration facilities located in Sutter County, California,
for a net book value of $108.6 million. Under the terms of the agreement, we
received approximately $559,000 for the sale of all our rights, title and
interest in the stock of Calpine Greenleaf Corporation, and transferred all
non-recourse project financing of $71.6 million and deferred taxes of $21.4
million. A loss of $15.6 million was recorded on the balance sheet and is being
amortized over the term of the lease through June 2014. Additionally, we have an
early purchase option expiring September 30, 2003.
 
     On September 28, 1998, we entered into a partnership agreement with Energy
Management, Inc. ("EMI") to acquire an ownership interest in a 265 megawatt
gas-fired plant under construction in Tiverton, Rhode Island. EMI and Calpine
will be co-general partners for this project, with EMI acting as the managing
general partner. We invested $40.0 million of equity in the power project, which
is scheduled to commence commercial operation in May 2000. We will receive 62.8%
of all cash and income distributions from the Tiverton project until we receive
a 10.5% pre-tax rate of return. Thereafter, we will receive 50% of all
distributions.
 
     On November 18, 1998, we entered into a partnership agreement with EMI to
acquire an ownership interest in a 265 megawatt gas-fired plant under
construction in Rumford, Maine. EMI and Calpine will be co-general partners for
this project, with EMI acting as the managing general partner. We invested $40.0
million of equity in the power project, which is scheduled to commence
commercial operation in July 2000. We will receive 66 2/3% of all cash and
income distributions from the Rumford project until we receive a 10.5% pre-tax
rate of return. Thereafter, we will receive 50% of all distributions.
 
SELECTED OPERATING INFORMATION
 
     Set forth below is certain selected operating information for the power
plants and steam fields, for which results are consolidated in our consolidated
statements of operations. The information set forth under power plants consists
of the results for the West Ford Flat Power Plant, Bear Canyon Power Plant,
Greenleaf 1 & 2 Power Plants, Watsonville Power Plant, King City Power Plant,
Gilroy Power Plant, the Bethpage Power Plant since its acquisition on February
5, 1998, the Texas City and Clear Lake Power Plants since their acquisition on
March 31, 1998, the Pasadena Power Plant since it began commercial operation on
July 7, 1998, the Sonoma Power Plant since its acquisition on July 17, 1998 and
the Pittsburg Power Plant since its acquisition on July 21, 1998. The
information set forth under steam fields consists of the results for the PG&E
Unit 13 and
 
                                       26
<PAGE>   32
 
Unit 16 Steam Fields, the SMUDGEO #1 Steam Fields and the Thermal Power Company
Steam Fields.
 
<TABLE>
<CAPTION>
                                                   YEAR ENDED DECEMBER 31,
                              ------------------------------------------------------------------
                                 1994          1995          1996          1997          1998
                              ----------    ----------    ----------    ----------    ----------
                                                    (DOLLARS IN THOUSANDS)
<S>                           <C>           <C>           <C>           <C>           <C>
POWER PLANTS:
  Electricity revenue (1):
  Energy....................  $   45,912    $   54,886    $   93,851    $  110,879    $  252,178
  Capacity..................  $    7,967    $   30,485    $   65,064    $   84,296    $  193,535
  Megawatt hours produced...     447,177     1,033,566     1,985,404     2,158,008     9,864,080
  Average energy price per
    kilowatt hour (2).......     10.267c        5.310c        4.727c        5.138c        2.557c
STEAM FIELDS:
  Steam revenue (3):
  Calpine...................  $   32,631    $   39,669    $   40,549    $   42,102    $   36,130
  Other interest............  $    2,051    $       --    $       --    $       --    $       --
  Megawatt hours produced...   2,156,492     2,415,059     2,528,874     2,641,422     2,323,623
  Average price per kilowatt
    hour....................      1.608c        1.643c        1.603c        1.594c        1.555c
</TABLE>
 
- ---------------
(1) Electricity revenue is composed of fixed capacity payments, which are not
    related to production, and variable energy payments, which are related to
    production.
 
(2) Represents variable energy revenue divided by the kilowatt-hours produced.
    The significant increase in capacity revenue and the accompanying decline in
    average energy price per kilowatt-hour since 1994 primarily reflects the
    increase in our megawatt hour production as a result of additional gas-fired
    power plants.
 
(3) The decline in steam revenue between 1998 and 1997 reflects the acquisition
    and consolidation of the Sonoma Power Plant and the related steam fields. We
    recently announced several acquisitions which we expect to be completed
    during the first part of 1999. Once these acquisitions are completed we will
    only record electricity revenue.
 
RESULTS OF OPERATIONS
 
     YEAR ENDED DECEMBER 31, 1998 COMPARED TO YEAR ENDED DECEMBER 31, 1997
 
Revenue -- Total revenue increased 101% to $555.9 million in 1998 compared to
$276.3 million in 1997.
 
     Electricity and steam sales revenue increased 114% to $507.9 million in
1998 compared to $237.3 million in 1997. The increase is primarily attributable
to the acquisition of the remaining interest in the Texas City, Clear Lake and
Bethpage Power Plants and the acquisition of the Pittsburg Power Plant. These
power plants accounted for $245.2 million in additional electricity revenues in
1998. We benefited from the startup of our power plant in Pasadena, Texas, which
became operational in July 1998. This power plant contributed $30.5 million in
revenue during 1998. During 1998, we produced 9,864,080 total electricity
megawatt hours, which was 7,706,072 megawatt hours higher than the same period
in 1997, as a result of the factors described above. We recently announced three
acquisitions, which we expect to complete during 1999, upon government approval.
These acquisitions when completed will eliminate steam revenue for The Geysers,
reflecting the consolidation of the acquired power plants and related steam
fields.
 
                                       27
<PAGE>   33
 
     Service contract revenue increased 98% to $20.2 million in 1998 compared to
$10.2 million in 1997. The $10.0 million increase was primarily due to $3.3
million for fuel management fees, and $7.5 million for third party excess gas
sales.
 
     Income from unconsolidated investments in power projects increased 59% to
$25.2 million in 1998 compared to $15.8 million in 1997. The increase of $9.4
million is primarily attributable to our investments in the Lockport, Stony
Brook and Kennedy International Airport Power Plants, which contributed $5.2
million of equity income during 1998, as well as $2.5 million of equity income
from the Bayonne Power Plant. For the year ended December 31, 1998, we also
recorded $11.7 million of equity income from the Sumas Power Plant compared to
$8.5 million for the same period in 1997. These increases in equity income were
partially offset by a $1.1 million decrease from the Auburndale Power Plant.
 
     Interest income on loans to power projects decreased 80% to $2.6 million in
1998 compared to $13.0 million in 1997. This decrease was attributable to the
acquisition of the remaining 50% interest in TCC on March 31, 1998 and the sale
of a note receivable in December 1997.
 
Cost of revenue -- Cost of revenue increased to $375.3 million in 1998 compared
to $153.3 million in 1997. The increase of $222.0 million in 1998 was primarily
attributable to increased plant operating, fuel and depreciation expenses as a
result of the acquisition of the remaining interest in the Texas City, Clear
Lake and Bethpage Power Plants, the acquisition of the Pittsburg Power Plant and
the startup of the Pasadena Power Plant. Additionally, service contract expenses
increased $8.8 million for the year ended December 31, 1998, of which $6.6
million was related to costs associated with the sale of third party excess gas
and a $1.8 million increase for fuel management contracts.
 
General and administrative expenses -- General and administrative expenses
increased 46% to $26.8 million in 1998 compared to $18.3 million in 1997. The
increase was attributable to the continued growth in personnel and overhead
costs necessary to support the overall growth in our operations.
 
Interest expense -- Interest expense increased 41% to $86.7 million in 1998
compared to $61.5 million in 1997. The increase was primarily attributable to
interest expense of $35.0 million related to the senior notes issued in 1998 and
1997. This increase was partially offset by $3.5 million for the repayment of
non-recourse project financing for our Geysers facilities, $2.9 million for
reduction of the TCC debt, $2.0 million for reduction of the indebtedness of the
Greenleaf 1 & 2 Power Plants and $1.7 million of interest capitalized on the
development and construction of power projects.
 
Interest income -- Interest income decreased 14% to $12.3 million in 1998
compared to $14.3 million in 1997. The decrease was primarily attributable to
less interest earned on restricted cash in 1998.
 
Other income, net -- Other income decreased 66% to $1.1 million in 1998 compared
to $3.2 million in 1997. The decrease was primarily attributable to gas refunds
received in 1997.
 
Provision for income taxes -- The effective income tax rate was approximately
37% in 1998 compared to 35% in 1997. The effective rates were lower than the
statutory rate (federal and state) primarily due to depletion in excess of tax
basis benefits at our
 
                                       28
<PAGE>   34
 
geothermal facilities, and a decrease in the California tax liability due to our
expansion into states other than California.
 
     YEAR ENDED DECEMBER 31, 1997 COMPARED TO YEAR ENDED
     DECEMBER 31, 1996
 
Revenue -- Total revenue increased 29% to $276.3 million in 1997 compared to
$214.6 million in 1996.
 
     Electricity and steam sales revenue increased 19% to $237.3 million in 1997
compared to $199.5 million in 1996. Electricity and steam sales revenue for 1997
reflected a full year of operation at the Gilroy and King City Power Plants,
which contributed to increases in electricity and steam sales revenue in 1997
compared to 1996 of $25.4 million, and $4.3 million, respectively. Electricity
and steam sales revenue for 1997 compared to 1996 was also $6.0 million higher
at the Bear Canyon and West Ford Flat Power Plants as a result of increased
production and an increase in fixed energy prices to 13.83c per kilowatt-hour.
During 1996, the Bear Canyon and West Ford Flat Power Plants experienced the
maximum curtailment allowed under their power sales agreements with PG&E. In May
1997, the power sales agreements for the Bear Canyon and West Ford Flat Power
Plants were modified to remove curtailment. Without such curtailment, these
plants generated an additional $4.2 million in revenues in 1997 as compared to
1996. In addition, Thermal Power Company ("TPC") also contributed $2.7 million
more revenue for 1997 than 1996, primarily due to increased steam sales under
the alternative pricing agreement entered into with PG&E in March 1996.
 
     Service contract revenue increased to $10.2 million in 1997 compared to
$6.5 million in 1996. Service contract revenue during 1996 reflected a $2.8
million loss from our electricity trading operations. The increase in service
contract revenue for 1997 was also attributable to $2.8 million of revenue from
the Texas City and Clear Lake Power Plants, which were acquired in June 1997.
 
     Income from unconsolidated investments in power projects increased to $15.8
million in 1997 compared to $6.5 million during 1996. The increase in 1997
compared to 1996 was primarily due to equity income of $6.3 million from our
June 1997 investment in the Texas City and Clear Lake Power Plants and an
increase in equity income of $2.2 million from our investment in Sumas
Cogeneration Company ("Sumas"). In accordance with a power sales agreement with
Puget Sound Power and Light Company, operations at Sumas were significantly
displaced from February to July 1997, and, in exchange, the Sumas Power Plant
received a higher price for energy sold and certain other payments. In addition,
the partnership agreement governing Sumas was amended in September 1997 to
increase our percentage of distributions.
 
     Interest income on loans to power projects increased to $13.0 million in
1997 compared to $2.1 million in 1996. The increase was primarily related to
interest income on the loans made by Calpine Finance Company, a wholly-owned
subsidiary of our company, to the Texas City and Clear Lake Power Plants, and to
interest income on the loans to the sole shareholder of Sumas Energy, Inc., our
partner in Sumas.
 
Cost of revenue -- Cost of revenue increased 19% to $153.3 million in 1997
compared to $129.2 million in 1996. Plant operating, depreciation, and operating
lease expenses at the Gilroy and King City Power Plants for 1997 reflected a
full year of operations, which
 
                                       29
<PAGE>   35
 
contributed to increases in cost of revenue in 1997 compared to 1996 of $13.0
million and $8.3 million, respectively.
 
Project development expenses -- Project development expenses increased 92% to
$7.5 million in 1997 compared to $3.9 million in 1996, due primarily to expanded
acquisition and development activities.
 
General and administrative expenses -- General and administrative expenses
increased 24% to $18.3 million in 1997 compared to $14.7 million in 1996. The
increases were primarily due to additional personnel and related expenses
necessary to support our expanding operations.
 
Interest expense -- Interest expense increased 36% to $61.5 million in 1997 from
$45.3 million in 1996. The increase was attributable to: (1) $10.8 million of
interest expense related to the 8 3/4% Senior Notes Due 2007 issued in July and
September 1997, (2) a $7.3 million increase in interest expense related to the
10 1/2% Senior Notes Due 2006 issued May 1996, (3) a $6.4 million increase in
interest expense on debt related to the Gilroy Power Plant acquired in August
1996 and (4) $5.4 million of interest expense on debt related to the acquisition
of the Texas City and Clear Lake Power Plants. These increases were offset by
$6.2 million of interest capitalized for the development and construction of
power plants, and a $7.6 million decrease in interest expense at Calpine Geysers
Company and TPC due to repayment of debt.
 
Interest income -- Interest income increased 66% to $14.3 million for 1997
compared with $8.6 million for 1996. Interest income earned on collateral
securities purchased in April 1996 in connection with the King City Power Plant
contributed to an increase in interest income of $1.2 million in 1997 as
compared to 1996. In addition, higher cash and cash equivalent balances
resulting from the issuance of the 8 3/4% Senior Notes Due 2007 during 1997
resulted in higher interest income for 1997 as compared to 1996.
 
Other income, net -- Other income, net, increased to $3.2 million for 1997
compared with expense of $2.3 million for 1996. In 1997, we recorded a $1.1
million gain on the sale of a note receivable and received a refund of $961,000
from PG&E. In 1996, we recorded a $3.7 million loss for uncollectible amounts
related to an acquisition project.
 
Provision for income taxes -- The effective rate for the income tax provision
was approximately 35% in 1997 and 33% in 1996. The effective rates were lower
than the statutory tax rate (federal and state) primarily due to depletion in
excess of tax basis benefits at our geothermal facilities, a decrease in the
California taxes paid due to our expansion into states other than California,
and a revision of prior years' tax estimates.
 
                                       30
<PAGE>   36
 
LIQUIDITY AND CAPITAL RESOURCES
 
     To date, we have obtained cash from our operations, borrowings under our
credit facilities and other working capital lines, sale of debt and equity, and
proceeds from non-recourse project financing. We utilized this cash to fund our
operations, service debt obligations, fund the acquisition, development and
construction of power generation facilities, finance capital expenditures and
meet our other cash and liquidity needs. The following table summarizes our cash
flow activities for the periods indicated:
 
<TABLE>
<CAPTION>
                                   YEAR ENDED DECEMBER 31,
                             -----------------------------------
                               1996         1997         1998
                             ---------    ---------    ---------
                                       (IN THOUSANDS)
                                       --------------
<S>                          <C>          <C>          <C>
Cash flows from:
  Operating activities.....  $  59,944    $ 108,461    $ 171,233
  Investing activities.....   (330,937)    (402,158)    (406,657)
  Financing activities.....    345,153      246,240      283,443
                             ---------    ---------    ---------
          Total............  $  74,160    $ (47,457)   $  48,019
                             =========    =========    =========
</TABLE>
 
     Operating activities for 1998 provided $171.2 million, consisting of
approximately $74.3 million of depreciation and amortization, $45.7 million of
net income, $34.4 million of distributions from unconsolidated investments in
power projects, $13.6 million of deferred income taxes, $5.2 million net
decrease in operating assets, and a $23.4 million net increase in operating
liabilities. This was offset by $25.2 million of income from unconsolidated
investments.
 
     Investing activities for 1998 used $406.7 million, primarily due to $158.1
million for the acquisition of the remaining 50% interest in the Texas City and
Clear Lake Power Plants, $42.4 million for the acquisition of the remaining 55%
interest in the Bethpage Power Plant, $24.0 million of capital expenditures
related to the construction of the Pasadena Power Plant, $13.1 million for the
acquisition of the Pittsburg Power Plant, $11.9 million for the acquisition of
the Sonoma Power Plant, $74.2 million of other capital expenditures, $16.2
million of capitalized project development costs, $40.0 million for the
acquisition of an equity interest in the Tiverton Power Plant, $40.0 million for
the acquisition of an equity interest in the Rumford Power Plant, $7.0 million
of interest capitalized on construction projects, offset by $559,000 related to
the sale and leaseback transaction of the Greenleaf 1 & 2 Power Plants, the
receipt of $13.8 million of loan payments, $6.0 million of maturities of
collateral securities in connection with the King City Power Plant, and $1.1
million of restricted cash.
 
     Financing activities for 1998 provided $283.4 million of cash consisting of
$52.1 million of borrowings for the construction of the Pasadena Power Plant,
$5.8 million of borrowings for contingent consideration in connection with the
acquisition of the Gilroy Power Plant, $394.9 million of net proceeds from
additional financings, and $1.1 million for the issuance of common stock,
partially offset by $162.1 million in repayment of non-recourse project
financing, $8.3 million of repurchase of Senior Notes Due 2006 which includes a
premium paid and accrued interest to the date of repurchase.
 
     At December 31, 1998, cash and cash equivalents were $96.5 million and
working capital was $86.9 million. For 1998, cash and cash equivalents increased
by $48.0 million and working capital increased by $112.6 million as compared to
December 31, 1997.
 
                                       31
<PAGE>   37
 
     As a developer, owner and operator of power generation facilities, we are
required to make long-term commitments and investments of substantial capital
for our projects. We historically have financed these capital requirements with
cash from operations, borrowings under our credit facilities, other lines of
credit, non-recourse project financing or long-term debt, and the sale of
equity. We expect to commit significant capital in the near future as a result
of development projects and pending acquisitions which have been announced,
including the Westbrook, Sutter, South Point and Magic Valley Power Plants. We
are also in the process of completing three acquisitions comprising of 14
geothermal power plants located in The Geysers and certain related steam fields.
 
     We continue to evaluate current and forecasted cash flow as a basis for
financing operating requirements and capital expenditures. We believe that we
will have sufficient liquidity from cash flow from operations, borrowings
available under the lines of credit and working capital to satisfy all
obligations under outstanding indebtedness, to finance anticipated capital
expenditures and to fund working capital requirements for the next twelve
months.
 
     On March 31, 1998, we sold $300.0 million of 7 7/8% Senior Notes Due 2008
which mature on April 1, 2008, with interest payable semi-annually on April 1
and October 1 of each year commencing October 1, 1998 (See note 7 to the notes
to our consolidated financial statements). On July 24, 1998, we sold an
additional $100.0 million of 7 7/8% Senior Notes Due 2008. After deducting
discounts to initial purchasers and expenses of the offerings, the net proceeds
from the sale of the Senior Notes Due 2008 were approximately $392.3 million.
(See note 7 to the notes to our consolidated financial statements).
 
     At December 31, 1998, we had a $100.0 million revolving credit facility
available with a consortium of commercial lending institutions. We had no
borrowings and $26.4 million of letters of credit outstanding under the credit
facility (See note 8 to the notes to our consolidated financial statements). The
credit facility contains certain restrictions that limit or prohibit, among
other things, the ability of Calpine or its subsidiaries to incur indebtedness,
make payments of certain indebtedness, pay dividends, make investments, engage
in transactions with affiliates, create liens, sell assets and engage in mergers
and consolidations.
 
     At December 31, 1998, we also had $105.0 million of outstanding 9 1/4%
Senior Notes Due 2004, which mature on February 1, 2004, with interest payable
semi-annually on February 1 and August 1 of each year. In addition, we had
$171.8 million of outstanding 10 1/2% Senior Notes Due 2006, which mature on May
15, 2006, with interest payable semi-annually on May 15 and November 15 of each
year. During 1997, we issued $275.0 million of 8 3/4% Senior Notes Due 2007,
which mature on July 15, 2007, with interest payable semi-annually on January 15
and July 15 of each year.
 
     At December 31, 1998, we had a $12.0 million letter of credit outstanding
with The Bank of Nova Scotia to secure performance of the Clear Lake Power
Plant.
 
     We have a $1.1 million working capital line with a commercial lender that
may be used to fund short-term working capital commitments and letters of
credit. At December 31, 1998, we had no borrowings under this working capital
line and $74,000 of letters of credit outstanding. Borrowings accrue interest at
prime plus 1%.
 
                                       32
<PAGE>   38
 
IMPACT OF RECENT ACCOUNTING PRONOUNCEMENTS
 
     In April 1998, the American Institute of Certified Public Accountants
("AICPA") issued Statement of Position ("SOP") No. 98-5, "Reporting on the Costs
of Start-Up Activities," which is effective for financial statements for fiscal
years beginning after December 15, 1998. For purposes of this SOP, start-up
activities are defined broadly as those one-time activities related to opening a
new facility, conducting business in a new territory, conducting business with a
new class of customer or beneficiary, initiating a new process in an existing
facility, or commencing some new operation. Start-up activities include
activities related to organizing a new entity (commonly referred to as
organization costs). We have assessed the impact and adopted SOP 98-5 as of
December 31, 1998, and determined it to be immaterial to our consolidated
financial statements.
 
     In June 1997, the Financial Accounting Standards Board ("FASB") issued
Statement of Financial Accounting Standards ("SFAS") No. 131, "Disclosures about
Segments of an Enterprise and Related Information." This Statement establishes
the reporting of information about operating segments in annual financial
statements and requires that enterprises report selected information about
operating segments in interim financial reports to shareholders. SFAS No. 131
also establishes standards for related disclosures about products and services,
geographic areas and major customers. SFAS No. 131 is effective for fiscal years
beginning after December 15, 1997. During 1998, we started the process of
decentralization of our operations and will complete this process during 1999.
This Statement will become effective upon completion of this process. We do not
believe that this pronouncement will have a material impact on our consolidated
financial statements.
 
     In June 1998, FASB also issued SFAS No. 133, "Accounting for Derivative
Instruments and Hedging Activities." The Statement establishes accounting and
reporting standards, requiring every derivative instrument be recorded in the
balance sheet as either an asset or liability measured at its fair value. The
Statement requires that changes in the derivative's fair value be recognized
currently in earnings unless specific hedge accounting criteria are met. Special
accounting for qualifying hedges allows a derivative's gains and losses to
offset related results on the hedged item in the income statement, and require
that a company formally document, designate, and assess the effectiveness of
transactions that receive hedge accounting.
 
     SFAS No. 133 is effective for fiscal years beginning after June 15, 1999.
The Statement must be applied to derivative instruments and to certain
derivative instruments embedded in hybrid contracts that were issued, acquired,
or substantively modified after December 31, 1997.
 
     We have not yet analyzed the impact of adopting SFAS No. 133 on the
financial statements and have not determined the timing of or method of the
adoption of SFAS No. 133. However the Statement could increase the volatility of
our earnings.
 
YEAR 2000 COMPLIANCE
 
     Year 2000 Compliance -- The "Year 2000 problem" refers to the fact that
some computer hardware, software and embedded systems were designed to read and
store dates using only the last two digits of the year.
 
     We are coordinating our efforts to address the impact of Year 2000 on our
business through a Year 2000 Project Team comprised of representatives from each
business unit and our Year 2000 Project Office. The Year 2000 Project Office is
charged with addressing
 
                                       33
<PAGE>   39
 
additional Year 2000 related issues including, but not limited to, business
continuation and other contingency planning. The Year 2000 Project Team meets
regularly to monitor the efforts of assigned staff and contractors to identify,
remediate and test our technology.
 
     The Year 2000 Project Team is focusing on four separate technology domains:
 
     - corporate applications, which include core business systems,
 
     - non-information technology, which includes all operating and control
       systems,
 
     - end-user computing systems (that is, systems that are not considered core
       business systems but may contain date calculations), and
 
     - business partner and vendor systems.
 
     Corporate Applications -- Corporate applications are those major core
systems, such as customer information, human resources and general ledger, for
which our Management Information Systems department has responsibility. We
utilize PeopleSoft for our major core systems. The PeopleSoft applications we
utilize are in operation and have been determined to be Year 2000 compliant.
 
     Non-Information Technology/Embedded Systems -- Non-information technology
includes such items as power plant operating and control systems,
telecommunications and facilities-based equipment (e.g. telephones and two-way
radios) and other embedded systems. Each business unit is responsible for the
inventory and remediation of its embedded systems. In addition, we are working
with the Electric Power Research Institute, a consortium of power companies,
including investor-owned utilities, to coordinate vendor contacts and product
evaluation. Because many embedded systems are similar across utilities, this
concentrated effort should help to reduce total time expended in this area and
help to ensure that our efforts are consistent with the efforts and practices of
other power companies and utilities.
 
     An Inventory phase for non-information technology/embedded systems was
completed in October 1998. An Initial Assessment phase was completed in December
1998. We plan to complete remediation of non-compliant systems by the second
quarter of 1999. To date, all embedded systems that we have identified can be
upgraded or modified within our current schedule. The schedule for addressing
Year 2000 issues with respect to mission critical embedded systems is as
follows:
 
<TABLE>
<CAPTION>
                        PERCENTAGE
PHASE                   COMPLETED      STATUS      ESTIMATED COMPLETION DATE
- -----                   ----------   -----------   --------------------------
<S>                     <C>          <C>           <C>
Inventory.............     100%      Complete      September 1998
Initial Assessment....     100%      Complete      November 1998
Detail Assessment.....      70%      In Progress   February 1999 - March 1999
Remediation...........      40%      In Progress   May 1999 - June 1999
Contingency                  5%
  Planning............               In Progress   June 1999 - Sept 1999
</TABLE>
 
     Testing of embedded systems is complex because some of the testing must be
completed during power plant scheduled maintenance outages. Much of the testing
will be accomplished in the spring of 1999 during regularly scheduled
maintenance outage periods. At that time, at least one typical unit of each
critical type will be tested by us or in cooperation with other power companies,
and the requirement for further testing will be determined.
 
     End-User Computing Systems -- Some of our business units have developed
systems, databases, spreadsheets, etc. that contain date calculations.
Compliance of individual
 
                                       34
<PAGE>   40
 
workstations is also included in this domain. These systems comprise a
relatively small percentage of the required modification in terms of both number
and criticality.
 
     Our end-user computing systems are being inventoried by each business unit
and evaluated and remediated by our MIS staff. We have completed approximately
10% of remediation and testing of the end-user computing systems, and we expect
to complete this process by mid-1999.
 
     Business Partner and Vendor Systems -- We have contracts with business
partners and vendors who provide products and services to us. We are vigorously
seeking to obtain Year 2000 assurances from these third parties. The Year 2000
Project Team and appropriate business units are jointly undertaking this effort.
We have sent letters and accompanying Year 2000 surveys to about 800 vendors and
suppliers. Over 400 responses have been received as of January 31, 1999. These
responses outline to varying degrees the approaches vendors are undertaking to
resolve Year 2000 issues within their own systems. Follow-up letters will be
sent to those vendors who have not responded or whose responses were inadequate.
 
     Contingency Planning -- Contingency and business continuation planning are
in various stages of development for critical and high-priority systems. Our
existing disaster response plan and other contingency plans are currently being
evaluated and will be adopted for use in case of any Year 2000-related
disruption. We expect to complete our contingency planning by September 1999.
 
     Costs -- The costs of expected modifications are currently estimated to be
approximately $1.7 million which will be charged to expense as incurred. From
January 1, 1998 through December 31, 1998, $158,000 has been charged to expense.
Approximately 9% of the estimated total cost was incurred in 1998, and the
remainder will be incurred in 1999 and 2000. These costs have been and will be
funded through operating cash flow. These estimates may change as additional
evaluations are completed and remediation and testing progress.
 
     Risks -- We currently expect to complete our Year 2000 efforts with respect
to critical systems by mid-1999. This schedule and our cost estimates may be
affected by, among other things, the availability of Year 2000 personnel, the
readiness of third parties, the timing for testing our embedded systems, the
availability of vendor resources to complete embedded system assessments and
produce required component upgrades and our ability to implement appropriate
contingency plans.
 
     We produce revenues by selling power we produce to customers. We depend on
transmission and distribution facilities that are owned and operated by
investor-owned utilities to deliver power to our customers. If either our
customers or the providers of transmission and distribution facilities
experience significant disruptions as a result of the Year 2000 problem, our
ability to sell and deliver power may be hindered, which could result in a loss
of revenue.
 
     The cost or consequences of a materially incomplete or untimely resolution
of the Year 2000 problem could adversely affect our future operations, financial
results or our financial condition.
 
                                       35
<PAGE>   41
 
                                    BUSINESS
 
OVERVIEW
 
     Calpine is a leading independent power company engaged in the development,
acquisition, ownership and operation of power generation facilities and the sale
of electricity predominantly in the United States. We have experienced
significant growth in all aspects of our business over the last five years.
Currently, we own interests in 22 power plants having an aggregate capacity of
2,729 megawatts and have three acquisition transactions pending in which we will
acquire 14 geothermal power plants with an aggregate capacity of 694 megawatts
and certain related steam fields. We also have six gas-fired projects under
construction having an aggregate capacity of 1,784 megawatts and have announced
plans to develop four gas-fired power plants with a total capacity of 2,580
megawatts. Upon completion of pending acquisitions and projects under
construction, we will have interests in 40 power plants having an aggregate
capacity of 5,207 megawatts, of which we will have a net interest in 4,271
megawatts. This represents significant growth from the 342 megawatts of capacity
we had at the end of 1993. Of this total generating capacity, 81% will be
attributable to gas-fired facilities and 19% will be attributable to geothermal
facilities.
 
     As a result of our expansion program, our revenues, cash flow, earnings and
assets have grown significantly over the last five years, as shown in the table
below.
 
<TABLE>
<CAPTION>
                                                              COMPOUND ANNUAL
                                      1993         1998         GROWTH RATE
                                    --------    ----------    ---------------
                                    (DOLLARS IN MILLIONS)
<S>                                 <C>         <C>           <C>
Total Revenue.....................   $ 69.9      $  555.9           51%
EBITDA............................     42.4         255.3           43%
Net Income........................      3.8          45.7           64%
Total Assets......................    302.3       1,728.9           42%
</TABLE>
 
     Since our inception in 1984, we have developed substantial expertise in all
aspects of the development, acquisition and operation of power generation
facilities. We believe that the vertical integration of our extensive
engineering, construction management, operations, fuel management and financing
capabilities provides us with a competitive advantage to successfully implement
our acquisition and development program and has contributed to our significant
growth over the past five years.
 
THE MARKET
 
     The power industry represents the third largest industry in the United
States, with an estimated end-user market of over $250 billion of electricity
sales in 1998 produced by an aggregate base of power generation facilities with
a capacity of approximately 750,000 megawatts. In response to increasing
customer demand for access to low-cost electricity and enhanced services, new
regulatory initiatives have been and are continuing to be adopted at both the
state and federal level to increase competition in the domestic power generation
industry. The power generation industry historically has been largely
characterized by electric utility monopolies producing electricity from old,
inefficient, high-cost generating facilities selling to a captive customer base.
Industry trends and regulatory initiatives have transformed the existing market
into a more competitive market where end users purchase electricity from a
variety of suppliers, including non-utility generators, power marketers, public
utilities and others.
 
                                       36
<PAGE>   42
 
     There is a significant need for additional power generating capacity
throughout the United States, both to satisfy increasing demand, as well as to
replace old and inefficient generating facilities. Due to environmental and
economic considerations, we believe this new capacity will be provided
predominantly by gas-fired facilities. We believe that these market trends will
create substantial opportunities for efficient, low-cost power producers that
can produce and sell energy to customers at competitive rates.
 
     In addition, as a result of a variety of factors, including deregulation of
the power generation market, utilities, independent power producers and
industrial companies are disposing of power generation facilities. To date,
numerous utilities have sold or announced their intentions to sell their power
generation facilities and have focused their resources on the transmission and
distribution segments. Many independent producers operating a limited number of
power plants are also seeking to dispose of their plants in response to
competitive pressures, and industrial companies are selling their power plants
to redeploy capital in their core businesses.
 
STRATEGY
 
     Our strategy is to continue our rapid growth by capitalizing on the
significant opportunities in the power market, primarily through our active
development and acquisition programs. In pursuing our proven growth strategy, we
utilize our extensive management and technical expertise to implement a fully
integrated approach to the acquisition, development and operation of power
generation facilities. This approach uses our expertise in design, engineering,
procurement, finance, construction management, fuel and resource acquisition,
operations and power marketing, which we believe provides us with a competitive
advantage. The key elements of our strategy are as follows:
 
     - Development and expansion of power plants. We are actively pursuing the
       development and expansion of highly efficient, low-cost, gas-fired power
       plants to replace old and inefficient generating facilities and meet the
       demand for new generation. Our strategy is to develop power plants in
       strategic geographic locations that enable us to utilize existing power
       generation assets and operate the power plants as integrated electric
       generation systems. This allows us to achieve significant operating
       synergies and efficiencies in fuel procurement, power marketing and
       operations and maintenance.
 
       In July 1998, we achieved a key milestone in our development program by
       completing the development of our 240 megawatt gas-fired power plant in
       Pasadena, Texas. The Pasadena Power Plant serves as a prototype for
       future development projects. We currently have six gas-fired projects
       under construction, representing an additional 1,784 megawatts of
       capacity. Of these new projects, we are expanding our Pasadena and Clear
       Lake facilities by an aggregate of 545 megawatts. In addition, four new
       gas-fired power plants, with a total capacity of 1,239 megawatts, are
       currently under construction in Dighton, Massachusetts; Tiverton, Rhode
       Island; Rumford, Maine; and Westbrook, Maine. We have also announced
       plans to develop four additional power generation facilities, totaling an
       estimated 2,580 megawatts of electricity, in California, Texas and
       Arizona.
 
     - Acquisition of power plants. Our strategy is to acquire power generating
       facilities that meet our stringent criteria, provide significant
       potential for revenue, cash flow and earnings growth and provide the
       opportunity to enhance the operating efficiencies of the plants. We have
       significantly expanded and diversified our project
 
                                       37
<PAGE>   43
 
       portfolio through the acquisition of power generation facilities through
       the completion of 23 acquisitions to date.
 
       We are currently in the process of completing three acquisitions
       comprising 14 geothermal power plants with an aggregate capacity of 694
       megawatts and certain related steam fields located in The Geysers,
       California. Historically, we have served as the steam supplier for these
       facilities, which have been owned and operated by PG&E. We anticipate
       that these acquisitions will enable us to consolidate our operations in
       The Geysers into a single ownership structure and to integrate the power
       plant and steam field operations, allowing us to optimize the efficiency
       and performance of the facilities. We believe that these acquisitions
       will provide us with significant synergies that utilize our expertise in
       geothermal power generation and position us to benefit from the demand
       for "green" energy in the competitive market.
 
     - Enhancement of the performance and efficiency of existing power
       projects. We continually seek to maximize the power generation potential
       of our operating assets and minimize our operating and maintenance
       expenses and fuel costs. This will become even more significant as our
       portfolio of power generation facilities expands to an aggregate of 40
       power plants with an aggregate capacity of 5,207 megawatts, after
       completion of our pending acquisitions and projects currently under
       construction. We focus on operating our plants as an integrated system of
       power generation, which enables us to minimize costs and maximize
       operating efficiencies. As of December 31, 1998, our power generation
       facilities have operated at an average availability of approximately
       96.5%. We believe that achieving and maintaining a low-cost of production
       will be increasingly important to compete effectively in the power
       generation market.
 
DESCRIPTION OF FACILITIES
 
     We currently have interests in 22 power generation facilities and three
steam fields with a current aggregate capacity of approximately 3,018 megawatts,
consisting of 18 gas-fired power plants with a total capacity of 2,602
megawatts, four geothermal power generation facilities with a total capacity of
127 megawatts, and three steam fields with a total capacity of 289 megawatts. We
also have three pending acquisitions of 14 geothermal power plants with an
aggregate capacity of 694 megawatts and certain related steam fields, six
gas-fired projects currently under construction with an aggregate capacity of
1,784 megawatts, and have announced the development of four additional power
plants with an aggregate capacity of 2,580 megawatts. Each of the power
generation facilities currently in operation produces electricity for sale to a
utility or other third-party end user. Thermal energy produced by the gas-fired
cogeneration facilities is sold to governmental and industrial users.
 
     The gas-fired and geothermal power generation projects in which we have an
interest produce electricity and thermal energy that are typically sold pursuant
to long-term power sales agreements. Revenue from a power sales agreement
usually consists of two components: energy payments and capacity payments.
Energy payments are based on a power plant's net electrical output where payment
rates may be determined by a schedule of prices covering a fixed number of years
under the power sales agreement, after which payment rates are usually indexed
to the fuel costs of the contracting utility or to general inflation indices.
Capacity payments are based on a power plant's net electrical output
 
                                       38
<PAGE>   44
 
and/or its available capacity. Energy payments are made for each kilowatt hour
of energy delivered, while capacity payments, under certain circumstances, are
made whether or not any electricity is delivered.
 
     Upon completion of the pending acquisitions and projects under
construction, we will provide operating and maintenance services for 31 of the
40 power plants and steam fields in which we have an interest. Such services
include the operation of power plants, geothermal steam fields, wells and well
pumps, gathering systems and gas pipelines. We also supervise maintenance,
materials purchasing and inventory control, manage cash flow, train staff and
prepare operating and maintenance manuals for each power generation facility
that we operate. As a facility develops an operating history, we analyze its
operation and may modify or upgrade equipment or adjust operating procedures or
maintenance measures to enhance the facility's reliability or profitability.
These services are performed under the terms of an operating and maintenance
agreement pursuant to which we are generally reimbursed for certain costs, paid
an annual operating fee and may also be paid an incentive fee based on the
performance of the facility. The fees payable to us are generally subordinated
to any lease payments or debt service obligations of non-recourse financing for
the project.
 
     In order to provide fuel for the gas-fired power generation facilities in
which we have an interest, natural gas reserves are acquired or natural gas is
purchased from third parties under supply agreements. We attempt to structure a
gas-fired power facility's fuel supply agreement so that gas costs have a direct
relationship to the fuel component of revenue energy payments. We currently hold
interests in geothermal leaseholds in The Geysers that produce steam that is
supplied to the power generation facilities owned by us for use in producing
electricity.
 
     Certain power generation facilities in which we have an interest have been
financed primarily with non-recourse project financing that is structured to be
serviced out of the cash flows derived from the sale of electricity, thermal
energy and/or steam produced by such facilities and provides that the
obligations to pay interest and principal on the loans are secured almost solely
by the capital stock or partnership interests, physical assets, contracts and/or
cash flow attributable to the entities that own the facilities. The lenders
under non-recourse project financing generally have no recourse for repayment
against us or any of our assets or the assets of any other entity other than
foreclosure on pledges of stock or partnership interests and the assets
attributable to the entities that own the facilities.
 
     Substantially all of the power generation facilities in which we have an
interest are located on sites which are leased on a long-term basis. See
"-- Properties."
 
                   [DEPICTION OF A MAP OF THE UNITED STATES,
            WITH MARKERS INDICATING THE LOCATION OF OUR FACILITIES]
 
                                       39
<PAGE>   45
 
<TABLE>
<CAPTION>
                                                                   MEGAWATTS
                                                            -----------------------
                                                   # OF      PLANT      CALPINE NET
                                                  PLANTS    CAPACITY     INTEREST
                                                  ------    --------    -----------
<S>                                               <C>       <C>         <C>
In operation....................................    22       2,729         2,065
Pending acquisitions............................    14         694           694
Under construction
  -- New facilities.............................     4       1,239           967
  -- Expansion projects.........................    --         545           545
Announced development...........................     4       2,580         2,140
                                                    --       -----         -----
                                                    44       7,787         6,411
                                                    ==       =====         =====
</TABLE>
 
                                       40
<PAGE>   46
 
     Set forth below is certain information regarding our operating power
plants, plants under construction, pending power plant acquisitions and
development projects.
 
<TABLE>
<CAPTION>
                            POWER                        NAMEPLATE       CALPINE     CALPINE NET
                          GENERATION                      CAPACITY       INTEREST     INTEREST
      POWER PLANT         TECHNOLOGY     LOCATION      (MEGAWATTS)(1)   PERCENTAGE   (MEGAWATTS)
      -----------         ----------   -------------   --------------   ----------   -----------
<S>                       <C>          <C>             <C>              <C>          <C>
OPERATING POWER PLANTS
Texas City..............  Gas-Fired        Texas             450.0          100%          450.0
Clear Lake..............  Gas-Fired        Texas             377.0          100%          377.0
Pasadena................  Gas-Fired        Texas             240.0          100%          240.0
Gordonsville............  Gas-Fired      Virginia            240.0           50%          120.0
Lockport................  Gas-Fired      New York            184.0         11.4%           20.9
Bayonne.................  Gas-Fired     New Jersey           165.0          7.5%           12.4
Auburndale..............  Gas-Fired       Florida            150.0           50%           75.0
Sumas(2)................  Gas-Fired     Washington           125.0           70%           87.5
King City...............  Gas-Fired     California           120.0          100%          120.0
Gilroy..................  Gas-Fired     California           120.0          100%          120.0
Kennedy International
  Airport...............  Gas-Fired      New York            107.0           50%           53.5
Pittsburg...............  Gas-Fired     California            70.0          100%           70.0
Sonoma..................  Geothermal    California            60.0          100%           60.0
Bethpage................  Gas-Fired      New York             57.0          100%           57.0
Greenleaf 1.............  Gas-Fired     California            49.5          100%           49.5
Greenleaf 2.............  Gas-Fired     California            49.5          100%           49.5
Stony Brook.............  Gas-Fired      New York             40.0           50%           20.0
Agnews..................  Gas-Fired     California            29.0           20%            5.8
Watsonville.............  Gas-Fired     California            28.5          100%           28.5
West Ford Flat..........  Geothermal    California            27.0          100%           27.0
Bear Canyon.............  Geothermal    California            20.0          100%           20.0
Aidlin..................  Geothermal    California            20.0            5%            1.0
PENDING ACQUISITIONS
Sonoma County (12 power
  plants)...............  Geothermal    California           544.0          100%          544.0
Lake County (2 power
  plants)...............  Geothermal    California           150.0          100%          150.0
PROJECTS UNDER
  CONSTRUCTION
Westbrook...............  Gas-Fired        Maine             540.0          100%          540.0
Pasadena Expansion......  Gas-Fired        Texas             510.0          100%          510.0
Tiverton(3).............  Gas-Fired    Rhode Island          265.0         62.8%          166.4
Rumford(4)..............  Gas-Fired        Maine             265.0         66.7%          176.8
Dighton(5)..............  Gas-Fired    Massachusetts         169.0           50%           84.5
Clear Lake Expansion....  Gas-Fired        Texas              35.0          100%           35.0
ANNOUNCED DEVELOPMENT
Delta Energy Center.....  Gas-Fired     California           880.0           50%          440.0
Magic Valley............  Gas-Fired        Texas             700.0          100%          700.0
South Point.............  Gas-Fired       Arizona            500.0          100%          500.0
Sutter..................  Gas-Fired     California           500.0          100%          500.0
</TABLE>
 
- ---------------
(1) Nameplate capacity may not represent the actual output for a facility at any
    particular time.
 
                                       41
<PAGE>   47
 
(2) See "-- Operating Power Plants -- Sumas Power Plant" for a description of
    our interest in the Sumas Power Plant. Based on our current estimates, these
    payments represent approximately 70% of distributable cash.
 
(3) See "Project Development and Acquisitions -- Project Development -- Projects
    Under Construction -- Tiverton Power Plant" for a description of our
    interest in the Tiverton Power Plant.
 
(4) See "Project Development and Acquisitions -- Project Development -- Projects
    Under Construction -- Rumford Power Plant" for a description of our interest
    in the Rumford Power Plant.
 
(5) See "Project Development and Acquisitions -- Project Development -- Projects
    Under Construction -- Dighton Power Plant" for a description of our interest
    in the Dighton Power Plant. Based on our current estimates, our interest
    represents our right to receive approximately 50% of project cash flow
    beginning at the commencement of commercial operation.
 
OPERATING POWER PLANTS
 
     Texas City Power Plant. The Texas City Power Plant is a 450 megawatt
gas-fired cogeneration facility located in Texas City, Texas. Electricity
generated by the Texas City Power Plant is sold under two separate long-term
agreements to (1) Texas Utilities Electric Company ("TUEC") under a power sales
agreement terminating on September 30, 2002, and (2) Union Carbide Corporation
("UCC") under a steam and electricity services agreement terminating on June 30,
1999. Each agreement contains payment provisions for capacity and electric
energy payments. Under a steam and electricity services agreement expiring
October 19, 2003, the Texas City Power Plant will supply UCC with 300,000 lbs/hr
of steam on a monthly average basis, with the required supply of steam not
exceeding 600,000 lbs/hr at any given time. During 1998, the Texas City Power
Plant generated approximately 2,517,316,000 kilowatt hours of electric energy
for sale to TUEC and UCC and approximately $188.3 million of revenue.
 
     Clear Lake Power Plant. The Clear Lake Power Plant is a 377 megawatt gas/
hydrogen-fired cogeneration facility located in Pasadena, Texas. Electricity
generated by the Clear Lake Power Plant is sold under three separate long-term
agreements to (1) Texas-New Mexico Power Company ("TNP") under a power sales
agreement terminating in 2004, (2) Houston Lighting and Power Company ("HL&P")
under a power sales agreement terminating in 2005, and (3) Hoechst Celanese
Chemical Group, Inc. ("HCCG") under a power sales agreement terminating in 2004.
Each power sales agreement contains payment provisions for capacity and energy
payments. Under a steam purchase and sale agreement expiring August 31, 2004,
the Clear Lake Power Plant will supply up to 900,000 lbs/hr of steam to HCCG.
During 1998, the Clear Lake Power Plant generated approximately 2,912,649,000
kilowatt hours of electric energy for sale to TNP, HL&P and HCCG and
approximately $89.3 million of revenue.
 
     Pasadena Power Plant. The Pasadena Power Plant is a 240 megawatt gas-fired
cogeneration facility located in Pasadena, Texas. Electricity generated by the
Pasadena Power Plant is sold under contract and into the open market. We entered
into an energy sales agreement with Phillips Petroleum Company ("Phillips")
terminating in 2018. Under this agreement, we provide 90 megawatts of
electricity and 200,000 lbs/hr of steam to Phillips' Houston Chemical Complex.
West Texas Utilities purchased 50 megawatts of capacity through the end of 1998.
In 1999, LG&E Energy Marketing will purchase up to
 
                                       42
<PAGE>   48
 
150 megawatts of electricity under a one-year agreement. TUEC is also under
contract to purchase up to 150 megawatts of electricity under a two-year
agreement beginning December 1, 1999. The remaining available electricity output
is sold into the competitive market through our power marketing organization.
During 1998, the Pasadena Power Plant generated approximately 812,314,000
kilowatt hours of electric energy with approximately $30.5 million of revenue.
 
     Gordonsville Power Plant. The Gordonsville Power Plant is a 240 megawatt
gas-fired cogeneration facility located near Gordonsville, Virginia. Electricity
generated by the Gordonsville Power Plant is sold to the Virginia Electric and
Power Company under two power sales agreements terminating on June 1, 2024, each
of which include payment provisions for capacity and energy. The Gordonsville
Power Plant sells steam to Rapidan Service Authority under the terms of a steam
purchase and sales agreement, which expires June 1, 2004. During 1998, the
Gordonsville Power Plant generated approximately 213,382,000 kilowatt hours of
electrical energy and approximately $37.4 million of revenue.
 
     Lockport Power Plant. The Lockport Power Plant is a 184 megawatt gas-fired,
combined-cycle cogeneration facility located in Lockport, New York. The facility
is owned and operated by Lockport Energy Associates, L.P. ("LEA"). We own an
indirect 11.36% limited partnership interest in LEA. Electricity and steam is
sold to General Motors Corporation ("GM") under an energy sales agreement
expiring in December 2007 for use at the GM Harrison plant, which is located on
a site adjacent to the Lockport Power Plant. Electricity is also sold to New
York State Electricity and Gas Company ("NYSEG") under a power purchase
agreement expiring October 2007. NYSEG is required to purchase all of the
electric power produced by the Lockport Power Plant not required by GM. For
1998, the Lockport Power Plant generated approximately 1,284,830,000 kilowatt
hours of electricity and had $118.6 million in revenue.
 
     Bayonne Power Plant. The Bayonne Power Plant is a 165 megawatt gas-fired
cogeneration facility located in Bayonne, New Jersey. The facility is primarily
owned by an affiliate of Cogen Technologies, Inc. We own an indirect 7.5%
limited partnership interest in the facility. Electricity generated by the
Bayonne Power Plant is sold under various power sales agreements to Jersey
Central Power & Light Company and Public Service Electric and Gas Company of New
Jersey. The Bayonne Power Plant also sells steam to two industrial entities.
During 1998, the Bayonne Power Plant generated approximately 1,399,860,000
kilowatt hours of electrical energy and approximately $116.6 million in revenue.
 
     Auburndale Power Plant. The Auburndale Power Plant is a 150 megawatt
gas-fired cogeneration facility located near the city of Auburndale, Florida.
Electricity generated by the Auburndale Power Plant is sold under various power
sales agreements to Florida Power Corporation ("FPC"), Enron Power Marketing and
Sonat Power Marketing. Auburndale sells 131.18 megawatts of capacity and energy
to FPC under three power sales agreements, each terminating at the end of 2013.
The Auburndale Power Plant sells steam under two steam purchase and sale
agreements. One agreement is with Cutrale Citrus Juices, USA, an affiliate of
Sucocitro Cutrale LTDA, expiring on July 1, 2014. The second agreement is with
Todhunter International, Inc., doing business as Florida Distillers Company,
expiring on July 1, 2009. During 1998, the Auburndale Power Plant generated
approximately 1,022,146,000 kilowatt hours of electrical energy and
approximately $49.6 million in revenue.
 
     Sumas Power Plant. The Sumas Power Plant is a 125 megawatt gas-fired,
combined cycle cogeneration facility located in Sumas, Washington. We currently
hold an ownership
 
                                       43
<PAGE>   49
 
interest in the Sumas Power Plant, which entitles us to receive certain
scheduled distributions during the next two years. Upon receipt of the scheduled
distributions, we will no longer have any ownership interest in the Sumas Power
Plant. Electrical energy generated by the Sumas Power Plant is sold to Puget
Sound Power & Light Company ("Puget") under the terms of a power sales agreement
terminating in 2013. Under the power sales agreement, Puget has agreed to
purchase an annual average of 123 megawatts of electrical energy. In addition to
the sale of electricity to Puget, pursuant to a long-term steam supply and dry
kiln lease agreement, the Sumas Power Plant produces and sells approximately
23,000 lbs/hr of low pressure steam to an adjacent lumber-drying facility owned
by Sumas, which has been leased to and is operated by Socco, Inc. During 1998,
the Sumas Power Plant generated approximately 915,227,280 kilowatt hours of
electrical energy and approximately $49.6 million of total revenue.
 
     King City Power Plant. The King City Power Plant is a 120 megawatt
gas-fired, combined-cycle cogeneration facility located in King City,
California. We operate the King City Power Plant under a long-term operating
lease for this facility with BAF Energy ("BAF"), terminating in 2018.
Electricity generated by the King City Power Plant is sold to Pacific Gas and
Electric Company ("PG&E") under a power sales agreement terminating in 2019. The
power sales agreement contains payment provisions for capacity and energy. In
addition to the sale of electricity to PG&E, the King City Power Plant produces
and sells thermal energy to a thermal host, Basic Vegetable Products, Inc., an
affiliate of BAF, under a long-term contract coterminous with the power sales
agreement. During 1998, the King City Power Plant generated approximately
428,825,000 kilowatt hours of electrical energy and approximately $45.6 million
of total revenue.
 
     Gilroy Power Plant. The Gilroy Power Plant is a 120 megawatt gas-fired
cogeneration facility located in Gilroy, California. Electricity generated by
the Gilroy Power Plant is sold to PG&E under a power sales agreement terminating
in 2018. In addition, the Gilroy Power Plant produces and sells thermal energy
to a thermal host, Gilroy Foods, Inc., under a long-term contract that is
coterminous with the power sales agreement. During 1998, the Gilroy Power Plant
generated approximately 477,628,000 kilowatt hours of electrical energy for sale
to PG&E and approximately $39.3 million in revenue.
 
     Kennedy International Airport Power Plant. The Kennedy International
Airport Power Plant is a 107 megawatt gas-fired cogeneration facility located at
John F. Kennedy International Airport in Queens, New York. The facility is owned
and operated by KIAC Partners ("KIAC"). We own an indirect 50% general
partnership interest in KIAC. Electricity and thermal energy generated by the
Kennedy International Airport Power Plant is sold to the Port Authority, and
incremental electric power is sold to Consolidated Edison Company of New York,
the New York Power Authority and other utility customers. Electric power and
chilled and hot water generated by the Kennedy International Airport Power Plant
is sold to the Port Authority under an energy purchase agreement that expires
November 2015. The Port Authority has a minimum thermal take requirement in an
amount sufficient to maintain the Kennedy International Airport Power Plant's QF
status. For 1998, the Kennedy International Airport Power Plant generated
approximately 533,755,000 kilowatt hours of electrical energy, 266,252 mmbtu of
chilled water and 178,405 mmbtu of hot water for sale to the Port Authority, and
generated approximately $56.1 million in revenue.
 
     Pittsburg Power Plant. The Pittsburg Power Plant is a 70 megawatt gas-fired
cogeneration facility, located at The Dow Chemical Company's ("Dow") Pittsburg,
California chemical facility. We sell up to 18 megawatts of electricity to Dow
under a
 
                                       44
<PAGE>   50
 
power sales agreement expiring in 2008. Surplus energy is sold to PG&E under an
existing power sales agreement. In addition, we sell approximately 200,000
lbs/hr of steam to Dow under an energy sales agreement expiring in 2003 and to
USS-POSCO Industries' nearby steel mill under a process steam contract expiring
in 2001. From its acquisition, in July 1998, through the end of 1998, the
Pittsburg Power Plant generated approximately 92,358,000 kilowatt hours of
electrical energy to Dow and PG&E and approximately $9.4 million in revenue.
 
     Sonoma Power Plant. The Sonoma Power Plant consists of a 60 megawatt
geothermal power plant and associated steam fields located in Sonoma County,
California. Electricity generated by the Sonoma Power Plant is sold to the
Sacramento Municipal Utility District ("SMUD") under a 50 megawatt agreement
terminating in 2001. In addition, SMUD has the option to purchase 10 megawatts
of peak power production through 2005. We market the excess electricity into the
California power market. From its acquisition, in June 1998, through the end of
1998, the Sonoma Power Plant generated approximately 215,433,000 kilowatt hours
of electrical energy and approximately $6.2 million in revenue.
 
     Bethpage Power Plant. The Bethpage Power Plant is a 57 megawatt gas-fired,
combined cycle cogeneration facility located adjacent to a Northrup Grumman
Corporation ("Grumman") facility in Bethpage, New York. Electricity and steam
generated by the Bethpage Power Plant are sold to Grumman under an energy
purchase agreement expiring August 2004. Electric power not sold to Grumman is
sold to Long Island Power Authority ("LIPA") under a generation agreement also
expiring August 2004. Grumman is also obligated to purchase a minimum of 158,000
klbs of steam per year from the Bethpage Power Plant. For 1998, the Bethpage
Power Plant generated approximately 474,991,000 kilowatt hours of electrical
energy for sale to Grumman and LIPA and approximately $32.9 million in revenue.
 
     Greenleaf 1 Power Plant. The Greenleaf 1 Power Plant is a 49.5 megawatt
gas-fired cogeneration facility located near Yuba City, California. We operate
this facility under an operating lease with Union Bank of California,
terminating in 2014 (the "Greenleaf Lease"). Electricity generated by the
Greenleaf 1 Power Plant is sold to PG&E under a power sales agreement
terminating in 2019 which contains payment provisions for capacity and energy.
In addition, the Greenleaf 1 Power Plant sells thermal energy, in the form of
hot exhaust to dry wood waste, to a thermal host which is owned and operated by
us. For 1998, the Greenleaf 1 Power Plant generated approximately 326,543,000
kilowatt hours of electrical energy for sale to PG&E and approximately $17.8
million in revenue.
 
     Greenleaf 2 Power Plant. The Greenleaf 2 Power Plant is a 49.5 megawatt
gas-fired cogeneration facility located near Yuba City, California. This
facility is also operated by us under the Greenleaf Lease. Electricity generated
by the Greenleaf 2 Power Plant is sold to PG&E under a power sales agreement
terminating in 2019 which includes payment provisions for capacity and energy.
In addition to the sale of electricity to PG&E, the Greenleaf 2 Power Plant
sells thermal energy to Sunsweet Growers, Inc. pursuant to a 30-year contract.
For 1998, the Greenleaf 2 Power Plant generated approximately 377,101,000
kilowatt hours of electrical energy for sale to PG&E and approximately $20.3
million in revenue.
 
     Stony Brook Power Plant. The Stony Brook Power Plant is a 40 megawatt
gas-fired cogeneration facility located on the campus of the State University of
New York at Stony Brook, New York ("SUNY"). The facility is owned by Nissequogue
Cogen Partners
 
                                       45
<PAGE>   51
 
("NCP"). We own an indirect 50% general partner interest in NCP. Steam and
electric power is sold to SUNY under an energy supply agreement expiring in
2023. Under the energy supply agreement, SUNY is required to purchase, and the
Stony Brook Power Plant is required to provide, all of SUNY's electric power and
steam requirements up to 36.125 megawatts of electricity and 280,000 lbs/hr of
process steam. The remaining electricity is sold to LIPA under a long-term
agreement. LIPA is obligated to purchase electric power generated by the
facility not required by SUNY. SUNY is required to purchase a minimum of 402,000
klbs per year of steam. For 1998, the Stony Brook Power Plant generated
approximately 326,584,000 kilowatt hours of electrical energy and 1,185,000 klbs
of steam for sale to SUNY and LIPA and approximately $31.1 million in revenue.
 
     Agnews Power Plant. The Agnews Power Plant is a 29 megawatt gas-fired,
combined-cycle cogeneration facility located on the East Campus of the
state-owned Agnews Developmental Center in San Jose, California. We hold a 20%
ownership interest in GATX Calpine-Agnews, Inc., which is the sole stockholder
of O.L.S. Energy-Agnews, Inc. ("O.L.S. Energy-Agnews"). O.L.S. Energy-Agnews
leases the Agnews Power Plant under a sale leaseback arrangement. Electricity
generated by the Agnews Power Plant is sold to PG&E under a power sales
agreement terminating in 2021 which contains payment provisions for capacity and
energy. In addition, the Agnews Power Plant produces and sells electricity and
approximately 7,000 lbs/hr of steam to the Agnews Developmental Center pursuant
to a 30-year energy service agreement. During 1998, the Agnews Power Plant
generated approximately 215,180,000 kilowatt hours of electrical energy and
total revenue of $11.7 million.
 
     Watsonville Power Plant. The Watsonville Power Plant is a 28.5 megawatt
gas-fired, combined cycle cogeneration facility located in Watsonville,
California. We operate the Watsonville Power Plant under an operating lease with
the Ford Motor Credit Company, terminating in 2009. Electricity generated by the
Watsonville Power Plant is sold to PG&E under a power sales agreement
terminating in 2009 which contains payment provisions for capacity and energy.
During 1998, the Watsonville Power Plant produced and sold steam to Farmers
Processing, a food processor. In addition, the Watsonville Power Plant sold
process water produced from its water distillation facility to Farmer's Cold
Storage, Farmer's Processing and Cascade Properties. For 1998, the Watsonville
Power Plant generated approximately 206,007,000 kilowatt hours of electrical
energy for sale to PG&E and approximately $11.4 million in revenue.
 
     West Ford Flat Power Plant. The West Ford Flat Power Plant consists of a 27
megawatt geothermal power plant and associated steam fields located in northern
California. Electricity generated by the West Ford Flat Power Plant is sold to
PG&E under a power sales agreement terminating in 2008 which contains payment
provisions for capacity and energy. During 1998, the West Ford Flat Power Plant
generated approximately 235,529,000 kilowatt hours of electrical energy for sale
to PG&E and approximately $34.6 million of revenue.
 
     Bear Canyon Power Plant. The Bear Canyon Power Plant consists of a 20
megawatt geothermal power plant and associated steam fields located in northern
California, two miles south of the West Ford Flat Power Plant. Electricity
generated by the Bear Canyon Power Plant is sold to PG&E under two 10 megawatt
power sales agreements terminating in 2008 which contain payment provisions for
capacity and energy. During 1998, the Bear Canyon Power Plant generated
approximately 176,508,000 kilowatt hours of electrical energy and approximately
$20.4 million of revenue.
 
                                       46
<PAGE>   52
 
     Aidlin Power Plant. The Aidlin Power Plant consists of a 20 megawatt
geothermal power plant and associated steam fields located in northern
California. We hold an indirect 5% ownership interest in the Aidlin Power Plant.
Electricity generated by the Aidlin Power Plant is sold to PG&E under two 10
megawatt power sales agreements terminating in 2009 which contain payment
provisions for capacity and energy. During 1998, the Aidlin Power Plant
generated approximately 170,046,000 kilowatt hours of electrical energy and
revenue of $24.4 million.
 
PROJECT DEVELOPMENT AND ACQUISITIONS
 
     We are actively engaged in the development and acquisition of power
generation projects. We have historically focused principally on the development
and acquisition of interests in gas-fired and geothermal power projects,
although we also consider projects that utilize other power generation
technologies. We have significant expertise in a variety of power generation
technologies and have substantial capabilities in each aspect of the development
and acquisition process, including design, engineering, procurement,
construction management, fuel and resource acquisition and management, financing
and operations.
 
ACQUISITIONS
 
     We will consider the acquisition of an interest in operating projects as
well as projects under development where we would assume responsibility for
completing the development of the project. In the acquisition of power
generation facilities, we generally seek to acquire an ownership interest in
facilities that offer us attractive opportunities for revenue and earnings
growth, and that permit us to assume sole responsibility for the operation and
maintenance of the facility. In evaluating and selecting a project for
acquisition, we consider a variety of factors, including the type of power
generation technology utilized, the location of the project, the terms of any
existing power or thermal energy sales agreements, gas supply and transportation
agreements and wheeling agreements, the quantity and quality of any geothermal
or other natural resource involved, and the actual condition of the physical
plant. In addition, we assess the past performance of an operating project and
prepare financial projections to determine the profitability of the project. We
generally seek to obtain a significant equity interest in a project and to
obtain the operation and maintenance contract for that project. See
"-- Strategy" and "Risk Factors -- We face risks associated with our power
project development and acquisition activities."
 
     We have grown substantially in recent years as a result of acquisitions of
interests in power generation facilities and steam fields. We believe that
although the domestic power industry is undergoing consolidation and that
significant acquisition opportunities are available, we are likely to confront
significant competition for acquisition opportunities. In addition, there can be
no assurance that we will continue to identify attractive acquisition
opportunities at favorable prices or, to the extent that any opportunities are
identified, that we will be able to consummate such acquisitions.
 
     Pending Acquisitions
 
     Sonoma County Power Plants. On January 26, 1999, we announced that we had
entered into definitive agreements to acquire 12 geothermal facilities from PG&E
in Sonoma County, California (the "Sonoma County Power Plants"), having a
combined capacity of 544 megawatts, for an aggregate investment of $139.0
million. We currently own a portion of the steam fields supplying the Sonoma
County Power Plants and have
 
                                       47
<PAGE>   53
 
agreed to purchase the remaining steam fields from Unocal Corporation for $101.0
million. We expect to complete the steam field acquisition in March 1999 and the
acquisition of the Sonoma County Power Plants upon receipt of approval by the
California Public Utilities Commission ("CPUC") and FERC, currently anticipated
to occur in April 1999. There can be no assurance that such approvals will be
obtained or that we will successfully complete these acquisitions.
 
     Lake County Power Plants. On December 1, 1998, we announced that we had
exercised our right of first refusal to acquire two geothermal facilities from
PG&E in Lake County, California (the "Lake County Power Plants"), having a
combined capacity of 150 megawatts, for $75.3 million. We currently own the
steam field operations currently supplying the Lake County Power Plants. We
expect to complete this acquisition upon receipt of the approval by the CPUC and
FERC, currently anticipated to occur in April 1999. There can be no assurance
that such approvals will be obtained or that we will successfully consummate
this acquisition.
 
     We anticipate that these acquisitions will enable us to consolidate our
operations in The Geysers into a single ownership structure and to integrate the
power plant and steam field operations, allowing us to optimize the efficiency
and performance of the facilities. We believe that these acquisitions will
provide us with significant synergies that leverage our expertise in geothermal
power generation and position us to benefit from the demand for "green" energy
in the competitive market.
 
PROJECT DEVELOPMENT
 
     The development of power generation projects involves numerous elements,
including evaluating and selecting development opportunities, designing and
engineering the project, obtaining power sales agreements, acquiring necessary
land rights, permits and fuel resources, obtaining financing and managing
construction. We intend to focus primarily on development opportunities where we
are able to capitalize on our expertise in implementing an innovative and fully
integrated approach to project development in which we control the entire
development process. Utilizing this approach, we believe that we are able to
enhance the value of our projects throughout each stage of development in an
effort to maximize our return on investment.
 
     We are pursuing the development of highly efficient, low-cost power plants
that seek to take advantage of inefficiencies in the electricity market. We
intend to sell all or a portion of the power generated by such plants into the
competitive market through a portfolio of short-, medium-and long-term power
sales agreements. We expect that these projects will represent a prototype for
our future plant developments. See "-- Strategy" and "Risk Factors -- We face
risks associated with our power project development and acquisition activities."
 
     The development of power generation facilities is subject to substantial
risks. In connection with the development of a power generation facility, we
must generally obtain power sales agreements, governmental permits and
approvals, fuel supply and transportation agreements, sufficient equity capital
and debt financing, electrical transmission agreements, site agreements and
construction contracts, and there can be no assurance that we will be successful
in doing so. In addition, project development is subject to certain
environmental, engineering and construction risks relating to cost-overruns,
delays and performance. Although we may attempt to minimize the financial risks
in the development of a project by securing a favorable long-term power sales
agreement, entering into power
 
                                       48
<PAGE>   54
 
marketing transactions, and obtaining all required governmental permits and
approvals, the development of a power project may require us to expend
significant sums for preliminary engineering, permitting and legal and other
expenses before it can be determined whether a project is feasible, economically
attractive or financeable. If we were unable to complete the development of a
facility, we would generally not be able to recover our investment in such a
facility. The process for obtaining initial environmental, siting and other
governmental permits and approvals is complicated and lengthy, often taking more
than one year, and is subject to significant uncertainties. As a result of
competition, it may be difficult to obtain a power sales agreement for a
proposed project, and the prices offered in new power sales agreements for both
electric capacity and energy may be less than the prices in prior agreements. We
cannot assure that we will be successful in the development of power generation
facilities in the future.
 
     Projects Under Construction
 
     Westbrook Power Plant. In February 1999, we acquired from Genesis Power
Corporation ("Genesis"), a New England based power developer, the development
rights to a 540 megawatt gas-fired combined-cycle power plant to be located in
Westbrook, Maine (the "Westbrook Power Plant"). It is estimated that the
development of the Westbrook Power Plant will cost approximately $300.0 million.
Construction commenced in February 1999 and commercial operation is scheduled
for early 2001. Upon completion, the Westbrook Power Plant will be operated by
our company. It is anticipated that the output generated by the Westbrook Power
Plant will be sold into the New England power market and to wholesale and retail
customers in the northeastern United States.
 
     Pasadena Expansion. We are currently expanding the Pasadena Power Plant by
an additional 510 megawatts. Construction began in November 1998 and commercial
operation is expected to begin in June 2000. The electricity output from this
expansion will be sold into the competitive market through our power sales
activities.
 
     Tiverton Power Plant. In September 1998, we invested $40.0 million of
equity in the development of a 265 megawatt gas-fired power plant to be located
in Tiverton, Rhode Island (the "Tiverton Power Plant"). The Tiverton Power Plant
is being developed by Energy Management Inc. ("EMI"). It is estimated that the
development of the Tiverton Power Plant will cost approximately $172.5 million.
For our investment in the Tiverton Power Plant, we will earn 62.8% of the
Tiverton Power Plant project cash flow until a specified pre-tax return is
reached, whereupon our company and EMI will share projected cash flows equally
through the remaining life of the project. Construction commenced in late 1998
and commercial operation is currently scheduled for 2000. Upon completion, the
Tiverton Power Plant will be operated by EMI and will sell its output in the New
England power market and to wholesale and retail customers in the northeastern
United States.
 
     Rumford Power Plant. In November 1998, we invested $40.0 million of equity
in the development of a 265 megawatt gas-fired power plant to be located in
Rumford, Maine (the "Rumford Power Plant"). The Rumford Power Plant is being
developed by EMI. It is estimated that the development of the Rumford Power
Plant will cost approximately $160.0 million. For our investment in the Rumford
Power Plant, we will earn 66.7% of the Rumford Power Plant project cash flow
until a specified pre-tax return is reached, whereupon our company and EMI will
share projected cash flows equally through the remaining life of the project.
Construction commenced in late 1998 and commercial operation is currently
scheduled for 2000. Upon completion, the Rumford Power Plant will
 
                                       49
<PAGE>   55
 
be operated by EMI and will sell its output in the New England power market and
to wholesale and retail customers in the northeastern United States.
 
     Dighton Power Plant. In October 1997, we invested $16.0 million in the
development of a 169 megawatt gas-fired combined-cycle power plant to be located
in Dighton, Massachusetts (the "Dighton Power Plant"). This investment, which is
structured as subordinated debt, will provide us with a preferred payment stream
at a rate of 12.07% per annum for a period of twenty years from the commercial
operation date. It is estimated that the development of the Dighton Power Plant
will cost approximately $120.0 million. The Dighton Power Plant is being
developed by EMI. Construction commenced in the fourth quarter of 1997 and
commercial operation is scheduled to begin in May 1999. Upon completion, the
Dighton Power Plant will be operated by EMI and will sell its output into the
New England power market and to wholesale and retail customers in the
northeastern United States.
 
     Clear Lake Expansion. We are currently expanding the Clear Lake Plant by 35
megawatts through certain capital improvements. Improvements began in late 1998
and commercial operation is expected to begin in December 1999. The electricity
output from this expansion will be sold into the competitive market through our
power sales activities.
 
     Announced Development Projects
 
     Delta Energy Center. On February 3, 1999, we, together with Bechtel
Enterprises, announced plans to develop an 880 megawatt gas-fired cogeneration
project in Pittsburg, California (the "Delta Energy Center"). The Delta Energy
Center will provide steam and electricity to the nearby Dow Chemical Company
facility and market the excess electricity into the California power market. We
anticipate that construction will commence in early 2000 and that operation of
the facility will commence in 2002. We are currently pursuing regulatory agency
permits for this project. On February 3, 1999, our company and Bechtel announced
that the Delta Energy Center has met the California Energy Commission's Data
Adequacy requirements in its Application for Certification.
 
     Magic Valley Power Plant. On May 26, 1998, we announced that we had signed
a 20-year power sales agreement to provide electricity to the Magic Valley
Electric Cooperative, Inc. of Mercedes, Texas beginning in 2001. The power will
be supplied by our Magic Valley Generating Station, a 700 megawatt natural
gas-fired power plant under development in Edinburg, Texas. Magic Valley, a
51,000 member non-profit electric cooperative, initially will purchase from 250
to 400 megawatts of capacity, with an option to purchase additional capacity. We
are marketing additional capacity to other wholesale customers, initially
targeting south Texas. Permitting for the Magic Valley plant is underway, with
construction expected to begin in late 1999.
 
     South Point Power Plant. In May 1998, we announced that we had entered into
a long-term lease agreement with the Fort Mojave Indian Tribe to develop a 500
megawatt gas-fired power plant (the "South Point Power Plant") on the tribe's
reservation in Mojave County, Arizona. The electricity generated will be sold to
the Arizona, Nevada and California power markets. We anticipate that the South
Point Power Plant will commence operation in 2000.
 
     Sutter Power Plant. In February 1997, we announced plans to develop a 500
megawatt gas-fired combined cycle project in Sutter County, in northern
California (the "Sutter Power Plant"). The Sutter Power Plant would be northern
California's first newly
 
                                       50
<PAGE>   56
 
constructed power plant. The Sutter Power Plant is expected to provide
electricity to the deregulated California power market commencing in the year
2000. We are currently pursuing regulatory agency permits for this project. On
January 21, 1998, we announced that the Sutter Power Plant has met the
California Energy Commission's Data Adequacy requirements in its Application for
Certification.
 
GAS FIELDS
 
     Montis Niger. On January 31, 1997, we purchased Montis Niger, Inc. a gas
production and pipeline company operating primarily in the Sacramento Basin in
northern California. On July 25, 1997, Montis Niger, Inc. was renamed Calpine
Gas Company. As of January 1, 1998, Calpine Gas Company had approximately 8.1
billion cubic feet of proven natural gas reserves and approximately 13,837 gross
acres and 13,738 net acres under lease in the Sacramento Basin. In addition,
Calpine Gas Company owns and operates an 80-mile pipeline delivering gas to the
Greenleaf 1 and 2 Power Plants which had been either produced by Calpine Gas
Company or purchased from third parties. Calpine Gas Company currently supplies
approximately 79% of the fuel requirements for the Greenleaf 1 and 2 Power
Plants.
 
     Sheridan. On January 27, 1999, we announced that we had acquired a 20%
interest in 82 billion cubic feet of proven natural gas reserves located in the
Sacramento Basin in northern California. Sheridan Energy, Inc. ("Sheridan") owns
the remaining 80% interest in these reserves. In addition, we signed a 10-year
agreement with Sheridan under which we will purchase all of Sheridan's
Sacramento Basin production, which currently approximates 20,000 mmbtu per day.
 
GOVERNMENT REGULATION
 
     We are subject to complex and stringent energy, environmental and other
governmental laws and regulations at the federal, state and local levels in
connection with the development, ownership and operation of its energy
generation facilities. Federal laws and regulations govern transactions by
electrical and gas utility companies, the types of fuel which may be utilized by
an electric generating plant, the type of energy which may be produced by such a
plant and the ownership of a plant. State utility regulatory commissions must
approve the rates and, in some instances, other terms and conditions under which
public utilities purchase electric power from independent producers and sell
retail electric power. Under certain circumstances where specific exemptions are
otherwise unavailable, state utility regulatory commissions may have broad
jurisdiction over non-utility electric power plants. Energy producing projects
also are subject to federal, state and local laws and administrative regulations
which govern the emissions and other substances produced, discharged or disposed
of by a plant and the geographical location, zoning, land use and operation of a
plant. Applicable federal environmental laws typically have both state and local
enforcement and implementation provisions. These environmental laws and
regulations generally require that a wide variety of permits and other approvals
be obtained before the commencement of construction or operation of an
energy-producing facility and that the facility then operate in compliance with
such permits and approvals.
 
                                       51
<PAGE>   57
 
FEDERAL ENERGY REGULATION
 
     PURPA
 
     The enactment of the Public Utility Regulatory Policies Act of 1978, as
amended ("PURPA") and the adoption of regulations thereunder by FERC provided
incentives for the development of cogeneration facilities and small power
production facilities (those utilizing renewable fuels and having a capacity of
less than 80 megawatts).
 
     A domestic electricity generating project must be a QF under FERC
regulations in order to take advantage of certain rate and regulatory incentives
provided by PURPA. PURPA exempts owners of QFs from the Public Utility Holding
Company Act of 1935, as amended ("PUHCA"), and exempts QFs from most provisions
of the Federal Power Act (the "FPA") and, except under certain limited
circumstances, state laws concerning rate or financial regulation. These
exemptions are important to us and our competitors. We believe that each of the
electricity generating projects in which we own an interest currently meets the
requirements under PURPA necessary for QF status.
 
     PURPA provides two primary benefits to QFs. First, QFs generally are
relieved of compliance with extensive federal, state and local regulations that
control the financial structure of an electric generating plant and the prices
and terms on which electricity may be sold by the plant. Second, the FERC's
regulations promulgated under PURPA require that electric utilities purchase
electricity generated by QFs at a price based on the purchasing utility's
"avoided cost," and that the utility sell back-up power to the QF on a
non-discriminatory basis. The term "avoided cost" is defined as the incremental
cost to an electric utility of electric energy or capacity, or both, which, but
for the purchase from QFs, such utility would generate for itself or purchase
from another source. The FERC regulations also permit QFs and utilities to
negotiate agreements for utility purchases of power at rates lower than the
utility's avoided costs. While public utilities are not explicitly required by
PURPA to enter into long-term power sales agreements, PURPA helped to create a
regulatory environment in which it has been common for long-term agreements to
be negotiated.
 
     In order to be a QF, a cogeneration facility must produce not only
electricity, but also useful thermal energy for use in an industrial or
commercial process for heating or cooling applications in certain proportions to
the facility's total energy output and must meet certain energy efficiency
standards. A geothermal facility may qualify as a QF if it produces less than 80
megawatts of electricity. Finally, a QF (including a geothermal or hydroelectric
QF or other qualifying small power producer) must not be controlled or more than
50% owned by an electric utility or by most electric utility holding companies,
or a subsidiary of such a utility or holding company or any combination thereof.
 
     We endeavor to develop our projects, monitor compliance by the projects
with applicable regulations and choose our customers in a manner which minimizes
the risks of any project losing its QF status. Certain factors necessary to
maintain QF status are, however, subject to the risk of events outside our
control. For example, loss of a thermal energy customer or failure of a thermal
energy customer to take required amounts of thermal energy from a cogeneration
facility that is a QF could cause the facility to fail requirements regarding
the level of useful thermal energy output. Upon the occurrence of such an event,
we would seek to replace the thermal energy customer or find another use for the
thermal energy which meets PURPA's requirements, but no assurance can be given
that this would be possible.
 
                                       52
<PAGE>   58
 
     If one of the facilities in which we have an interest should lose its
status as a QF, the project would no longer be entitled to the exemptions from
PUHCA and the FPA. This could trigger certain rights of termination under the
power sales agreement, could subject the project to rate regulation as a public
utility under the FPA and state law and could result in us inadvertently
becoming a public utility holding company by owning more than 10% of the voting
securities of, or controlling, a facility that would no longer be exempt from
PUHCA. This could cause all of our remaining projects to lose their qualifying
status, because QFs may not be controlled or more than 50% owned by such public
utility holding companies. Loss of QF status may also trigger defaults under
covenants to maintain QF status in the projects' power sales agreements, steam
sales agreements and financing agreements and result in termination, penalties
or acceleration of indebtedness under such agreements such that loss of status
may be on a retroactive or a prospective basis.
 
     Under the Energy Policy Act of 1992, if a project can be qualified as an
exempt wholesale generator ("EWG"), it will be exempt from PUHCA even if it does
not qualify as a QF. Therefore, another response to the loss or potential loss
of QF status would be to apply to have the project qualified as an EWG. However,
assuming this changed status would be permissible under the terms of the
applicable power sales agreement, rate approval from FERC and approval of the
utility would be required. In addition, the project would be required to cease
selling electricity to any retail customers (such as the thermal energy
customer) and could become subject to state regulation of sales of thermal
energy. See "-- Public Utility Holding Company Regulation."
 
     Currently, Congress is considering proposed legislation that would amend
PURPA by eliminating the requirement that utilities purchase electricity from
QFs at avoided costs. We do not know whether such legislation will be passed or
what form it may take. We believe that if any such legislation is passed, it
would apply only to new projects. As a result, although such legislation may
adversely affect our ability to develop new projects, we believe it would not
affect our existing QFs. There can be no assurance, however, that any
legislation passed would not adversely impact our existing projects.
 
     Public Utility Holding Company Regulation
 
     Under PUHCA, any corporation, partnership or other legal entity which owns
or controls 10% or more of the outstanding voting securities of a "public
utility company" or a company which is a "holding company" for a public utility
company is subject to registration with the SEC and regulation under PUHCA,
unless eligible for an exemption. A holding company of a public utility company
that is subject to registration is required by PUHCA to limit its utility
operations to a single integrated utility system and to divest any other
operations not functionally related to the operation of that utility system.
Approval by the SEC is required for nearly all important financial and business
dealings of a registered holding company. Under PURPA, most QFs are not public
utility companies under PUHCA.
 
     The Energy Policy Act of 1992, among other things, amends PUHCA to allow
EWGs, under certain circumstances, to own and operate non-QFs without subjecting
those producers to registration or regulation under PUHCA. The effect of such
amendments has been to enhance the development of non-QFs which do not have to
meet the fuel, production and ownership requirements of PURPA. We believe that
the amendments could benefit us by expanding our ability to own and operate
facilities that do not qualify
 
                                       53
<PAGE>   59
 
for QF status, but they have also resulted in increased competition by allowing
utilities to develop such facilities which are not subject to the constraints of
PUHCA.
 
     Federal Natural Gas Transportation Regulation
 
     We have an ownership interest in 18 gas-fired cogeneration projects. The
cost of natural gas is ordinarily the largest expense (other than debt costs) of
a project and is critical to the project's economics. The risks associated with
using natural gas can include the need to arrange transportation of the gas from
great distances, including obtaining removal, export and import authority if the
gas is transported from Canada; the possibility of interruption of the gas
supply or transportation (depending on the quality of the gas reserves purchased
or dedicated to the project, the financial and operating strength of the gas
supplier, and whether firm or non-firm transportation is purchased); and
obligations to take a minimum quantity of gas and pay for it (i.e., take-and-pay
obligations).
 
     Pursuant to the Natural Gas Act, FERC has jurisdiction over the
transportation and storage of natural gas in interstate commerce. With respect
to most transactions that do not involve the construction of pipeline
facilities, regulatory authorization can be obtained on a self-implementing
basis. However, pipeline rates and terms and conditions for such services are
subject to continuing FERC oversight.
 
STATE REGULATION
 
     State public utility commissions ("PUCs") have historically had broad
authority to regulate both the rates charged by, and the financial activities
of, electric utilities and to promulgate regulation for implementation of PURPA.
Since a power sales agreement becomes a part of a utility's cost structure
(generally reflected in its retail rates), power sales agreements with
independent electricity producers are potentially under the regulatory purview
of PUCs and in particular the process by which the utility has entered into the
power sales agreements. If a PUC has approved the process by which a utility
secures its power supply, a PUC is generally inclined to "pass through" the
expense associated with an independent power contract to the utility's retail
customer. However, a regulatory commission under certain circumstances may
disallow the full reimbursement to a utility for the cost to purchase power from
a QF. In addition, retail sales of electricity or thermal energy by an
independent power producer may be subject to PUC regulation depending on state
law. Independent power producers which are not QFs under PURPA, or EWGs pursuant
to the Energy Policy Act of 1992, are considered to be public utilities in many
states and are subject to broad regulation by a PUC, ranging from requirement of
certificate of public convenience and necessity to regulation of organizational,
accounting, financial and other corporate matters. States may assert
jurisdiction over the siting and construction of electric generating facilities
including QFs and, with the exception of QFs, over the issuance of securities
and the sale or other transfer of assets by these facilities.
 
     In the State of California, restructuring legislation was enacted in
September 1996 and was implemented in 1998. This legislation established an
Independent Systems Operator ("ISO") responsible for centralized control and
efficient and reliable operation of the state-wide electric transmission grid,
and a Power Exchange responsible for an efficient competitive electric energy
auction open on a non-discriminatory basis to all electric services providers.
Other provisions include the quantification and qualification of utility
stranded costs to be eligible for recovery through competitive transition
charges ("CTC"), market power mitigation through utility divestiture of fossil
generation plants, the
 
                                       54
<PAGE>   60
 
unbundling and establishment of rate structure for historical utility functions,
the continuation of public purpose programs and issues related to issuance of
rate reduction bonds.
 
     The California Energy Commission ("CEC") and Legislature have
responsibility for development of a competitive market mechanism for allocation
and distribution of funds made available by the legislation for enhancement of
in-state renewable resource technologies and public interest research and
development programs. Funds are to be available through the four-year transition
period to a fully competitive electric services industry.
 
     In addition to the significant opportunity provided for power producers
such as us through implementation of customer choice (direct access), the
California restructuring legislation both recognizes the sanctity of existing
contracts, provides for mitigation of utility horizontal market power through
divestiture of fossil generation and provides funds for continuation of public
services programs including fuel diversity through enhancement for in-state
renewable technologies (includes geothermal) for the four-year transition period
to a fully competitive electric services industry.
 
     Other states in which we conduct operations either have implemented or are
actively considering similar restructuring legislation.
 
     State PUCs also have jurisdiction over the transportation of natural gas by
local distribution companies ("LDCs"). Each state's regulatory laws are somewhat
different; however, all generally require the LDC to obtain approval from the
PUC for the construction of facilities and transportation services if the LDC's
generally applicable tariffs do not cover the proposed transaction. LDC rates
are usually subject to continuing PUC oversight.
 
REGULATION OF CANADIAN GAS
 
     The Canadian natural gas industry is subject to extensive regulation by
governmental authorities. At the federal level, a party exporting gas from
Canada must obtain an export license from the Canadian National Energy Board
("NEB"). The NEB also regulates Canadian pipeline transportation rates and the
construction of pipeline facilities. Gas producers also must obtain a removal
permit or license from provincial authorities before natural gas may be removed
from the province, and provincial authorities may regulate intra-provincial
pipeline and gathering systems. In addition, a party importing natural gas into
the United States first must obtain an import authorization from the U.S.
Department of Energy.
 
ENVIRONMENTAL REGULATIONS
 
     The exploration for and development of geothermal resources and the
construction and operation of power projects are subject to extensive federal,
state and local laws and regulations adopted for the protection of the
environment and to regulate land use. The laws and regulations applicable to us
primarily involve the discharge of emissions into the water and air and the use
of water, but can also include wetlands preservation, endangered species, waste
disposal and noise regulations. These laws and regulations in many cases require
a lengthy and complex process of obtaining licenses, permits and approvals from
federal, state and local agencies.
 
                                       55
<PAGE>   61
 
     Noncompliance with environmental laws and regulations can result in the
imposition of civil or criminal fines or penalties. In some instances,
environmental laws also may impose clean-up or other remedial obligations in the
event of a release of pollutants or contaminants into the environment. The
following federal laws are among the more significant environmental laws as they
apply to us. In most cases, analogous state laws also exist that may impose
similar, and in some cases more stringent, requirements on us as those discussed
below.
 
     Clean Air Act
 
     The Federal Clean Air Act of 1970 (the "Clean Air Act") provides for the
regulation, largely through state implementation of federal requirements, of
emissions of air pollutants from certain facilities and operations. As
originally enacted, the Clean Air Act sets guidelines for emissions standards
for major pollutants (i.e., sulfur dioxide and nitrogen oxide) from newly built
sources. In late 1990, Congress passed the Clean Air Act Amendments (the "1990
Amendments"). The 1990 Amendments attempt to reduce emissions from existing
sources, particularly previously exempted older power plants. We believe that
all of our operating plants are in compliance with federal performance standards
mandated for such plants under the Clean Air Act and the 1990 Amendments. With
respect to its Aidlin geothermal plant and one of its steam field pipelines, our
operations have, in certain instances, necessitated variances under applicable
California air pollution control laws. However, we believe that we are in
material compliance with such laws with respect to such facilities.
 
     Clean Water Act
 
     The Federal Clean Water Act (the "Clean Water Act") establishes rules
regulating the discharge of pollutants into waters of the United States. We are
required to obtain a wastewater and storm water discharge permit for wastewater
and runoff, respectively, from certain of our facilities. We believe that, with
respect to our geothermal operations, we are exempt from newly promulgated
federal storm water requirements. We believe that we are in material compliance
with applicable discharge requirements under the Clean Water Act.
 
     Resource Conservation and Recovery Act
 
     The Resource Conservation and Recovery Act ("RCRA") regulates the
generation, treatment, storage, handling, transportation and disposal of solid
and hazardous waste. We believe that we are exempt from solid waste requirements
under RCRA. However, particularly with respect to its solid waste disposal
practices at the power generation facilities and steam fields located at The
Geysers, we are subject to certain solid waste requirements under applicable
California laws. We believe that our operations are in material compliance with
such laws.
 
     Comprehensive Environmental Response, Compensation, and Liability Act
 
     The Comprehensive Environmental Response, Compensation and Liability Act of
1980, as amended ("CERCLA" or "Superfund"), requires cleanup of sites from which
there has been a release or threatened release of hazardous substances and
authorizes the United States Environmental Protection Agency ("EPA") to take any
necessary response action at Superfund sites, including ordering potentially
responsible parties ("PRPs") liable for the release to take or pay for such
actions. PRPs are broadly defined under CERCLA
 
                                       56
<PAGE>   62
 
to include past and present owners and operators of, as well as generators of
wastes sent to, a site. As of the present time, we are not subject to liability
for any Superfund matters. However, we generate certain wastes, including
hazardous wastes, and sends certain of our wastes to third-party waste disposal
sites. As a result, there can be no assurance that we will not incur liability
under CERCLA in the future.
 
COMPETITION
 
     The power generation industry is characterized by intense competition, and
we encounter competition from utilities, industrial companies and other power
producers. In recent years, there has been increasing competition in an effort
to obtain power sales agreements, and this competition has contributed to a
reduction in electricity prices. In addition, many states are implementing or
considering regulatory initiatives designed to increase competition in the
domestic power industry. In California, the CPUC issued decisions which provide
for direct access for all customers as of April 1, 1998. Regulatory initiatives
are also being considered in other states, including Texas, New York and states
in New England. See "Business -- Government Regulation -- State Regulation."
This competition has put pressure on electric utilities to lower their costs,
including the cost of purchased electricity, and increasing competition in the
future will increase this pressure.
 
EMPLOYEES
 
     As of December 31, 1998, we employed 458 people. None of our employees are
covered by collective bargaining agreements, and we have never experienced a
work stoppage, strike or labor dispute. We consider relations with our employees
to be good.
 
PROPERTIES
 
     Our principal executive office is located in San Jose, California, under a
lease that expires in June 2001.
 
     We have leasehold interests in 109 leases comprising 27,263 acres of
federal, state and private geothermal resource lands in The Geysers area in
northern California. These leases comprise our West Ford Flat Power Plant, Bear
Canyon Power Plant and certain steam fields. In the Glass Mountain and Medicine
Lake areas in northern California, we hold leasehold interests in 18 leases
comprising approximately 25,028 acres of federal geothermal resource lands.
 
     In general, under the leases, we have the exclusive right to drill for,
produce and sell geothermal resources from these properties and the right to use
the surface for all related purposes. Each lease requires the payment of annual
rent until commercial quantities of geothermal resources are established. After
such time, the leases require the payment of minimum advance royalties or other
payments until production commences, at which time production royalties are
payable. Such royalties and other payments are payable to landowners, state and
federal agencies and others, and vary widely as to the particular lease. The
leases are generally for initial terms varying from 10 to 20 years or for so
long as geothermal resources are produced and sold. Certain of the leases
contain drilling or other exploratory work requirements. In certain cases, if a
requirement is not fulfilled, the lease may be terminated and in other cases
additional payments may be required. We believe that our leases are valid and
that we have complied with all the requirements and conditions material to the
continued effectiveness of the leases. A number of our leases for
 
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<PAGE>   63
 
undeveloped properties may expire in any given year. Before leases expire, we
perform geological evaluations in an effort to determine the resource potential
of the underlying properties. We cannot assure that we will decide to renew any
expiring leases.
 
     We own 77 acres in Sutter County, California, on which the Greenleaf 1
Power Plant is located.
 
     We own Calpine Gas Company, which leases property covering approximately
13,837 gross acres and 13,738 net acres.
 
     See "-- Description of Facilities" for a description of the other material
leased or owned properties in which we have an interest. We believe that our
properties are adequate for our current operations.
 
LEGAL PROCEEDINGS
 
     On September 30, 1997, a lawsuit was filed by Indeck North American Power
Fund ("Indeck") in the Circuit Court of Cook County, Illinois against Norweb
plc. and certain other parties, including us. Some of Indeck's claims relate to
Calpine Gordonsville, Inc.'s acquisition of a 50% interest in Gordonsville
Energy from Northern Hydro Limited and Calpine Auburndale, Inc.'s acquisition of
a 50% interest in Auburndale Power Plant Partners Limited Partnership from
Norweb Power Services (No. 1) Limited. Indeck is claiming that Calpine
Gordonsville, Inc., Calpine Auburndale, Inc. and Calpine Corporation tortiously
interfered with Indeck's contractual rights to purchase such interests and
conspired with other parties to do so. Indeck is seeking $25.0 million in
compensatory damages, $25.0 million in punitive damages, and the recovery of
attorneys' fees and costs. In July 1998, the court granted motions to dismiss,
without prejudice, the claims against Calpine Gordonsville, Inc. and Calpine
Auburndale, Inc. In August 1998, Indeck filed an amended complaint and the
defendants filed motions to dismiss. A hearing on those motions is scheduled for
February 1999. We are unable to predict the outcome of these proceedings but we
do not believe that these proceedings will have a materially adverse effect on
our financial results.
 
     There is currently a dispute between Texas-New Mexico Power Company ("TNP")
and Clear Lake Cogeneration ("CLC"), which owns the Clear Lake Power Plant,
regarding certain costs and other amounts that TNP has withheld from payments
due under the power sales agreement from August 1997 until October 1998. TNP has
withheld approximately $450,000 per month related to transmission charges. In
October 1997, CLC filed a petition for declaratory order with the Texas Public
Utilities Commission ("Texas PUC") requesting a declaration that TNP's
withholding is in error, which petition is currently pending. Also, as of
September 30, 1998, TNP has withheld approximately $7.7 million of standby power
charges. CLC filed an action in Texas courts on October 2, 1997, alleging TNP's
breach of the power sales agreement and is seeking refund of the standby
charges. In October 1998, TNP and CLC reached an agreement in principle to
settle all outstanding disputes. The parties are currently finalizing the
documentation of the settlement which must be approved by the Texas PUC. Both
the Texas PUC action and the court action have been put on hold pending
completion of the settlement and we do not believe that these proceedings will
have a materially adverse effect on our financial results.
 
     An action was filed against Lockport Energy Associates ("LERA") and the New
York Public Service Commission ("NYPSC") in August 1997 by New York State
 
                                       58
<PAGE>   64
 
Electricity and Gas Company ("NYSEG") in the Federal District Court for the
Northern District of New York. NYSEG has requested the Court to direct NYPSC and
the Federal Energy Regulatory Commission (the "FERC") to modify contract rates
to be paid to the Lockport Power Plant. In October 1997, NYPSC filed a
cross-claim alleging that the FERC violated PURPA and the Federal Power Act by
failing to reform the NYSEG contract that was previously approved by the NYPSC.
Although we are unable to predict the outcome of this case, in any event, we
retain the right to require The Brooklyn Union Gas Company to purchase our
interest in the Lockport Power Plant for $18.9 million, less equity
distributions received by us, at any time before December 19, 2001.
 
     We and our affiliates are involved in various other claims and legal
actions arising out of the normal course of business. We do not expect that the
outcome of these proceedings will have a material adverse effect on our
financial position or results of operations, although we cannot assure you in
this regard.
 
                                       59
<PAGE>   65
 
                                   MANAGEMENT
 
DIRECTORS AND EXECUTIVE OFFICERS
 
     The following table sets forth certain information with respect to our
directors and executive officers.
 
<TABLE>
<CAPTION>
                NAME                  AGE                 POSITION
                ----                  ---                 --------
<S>                                   <C>   <C>
Peter Cartwright....................  69    Chairman of the Board, President,
                                            Chief Executive Officer and Director
Ann B. Curtis.......................  47    Executive Vice President, Chief
                                              Financial Officer, Corporate
                                              Secretary and Director
Jeffrey E. Garten...................  52    Director
Susan C. Schwab.....................  43    Director
George J. Stathakis.................  68    Director
John O. Wilson......................  60    Director
V. Orville Wright...................  78    Director
Lynn A. Kerby.......................  60    Executive Vice President-Operations
Robert D. Kelly.....................  41    Senior Vice President-Finance
</TABLE>
 
     Set forth below is certain information with respect to each director and
executive officer.
 
     Peter Cartwright founded our company in 1984 and has served as a Director
and as our President and Chief Executive Officer since inception. Mr. Cartwright
became Chairman of our board of directors in September 1996. From 1979 to 1984,
Mr. Cartwright was Vice President and General Manager of the Western Regional
Office of Gibbs & Hill, Inc. ("Gibbs & Hill"), an architect-engineering firm
that specialized in power engineering projects. From 1960 to 1979, Mr.
Cartwright worked for General Electric's Nuclear Energy Division. His
responsibilities included plant construction, project management and new
business development. He served on the board of directors of nuclear fuel
manufacturing companies in Germany, Italy and Japan. Mr. Cartwright was
responsible for General Electric's technology development and licensing programs
in Europe and Japan. Mr. Cartwright obtained a Master of Science Degree in Civil
Engineering from Columbia University in 1953 and a Bachelor of Science Degree in
Geological Engineering from Princeton University in 1952.
 
     Ann B. Curtis has served as Executive Vice President of our company since
August 1998, and before that was our Senior Vice President since September 1992,
and has been employed by us since our inception in 1984. Ms. Curtis became a
Director of our company in September 1996. She is responsible for our financial
and administrative functions, including the functions of general counsel,
corporate and project finance, accounting, human resources, public relations and
investor relations. Ms. Curtis also serves as our Chief Financial Officer and
Corporate Secretary. From our inception in 1984 through 1992, she served as our
Vice President for Management and Financial Services. Prior to joining our
company, Ms. Curtis was Manager of Administration for the Western Regional
Office of Gibbs & Hill.
 
     Jeffrey E. Garten became a Director of our company in January 1997. Mr.
Garten has served as Dean of the Yale School of Management and William S.
Beinecke Professor in the Practice of International Trade and Finance since
November 1995. Mr. Garten served
 
                                       60
<PAGE>   66
 
as Undersecretary of Commerce of International Trade in the United States
Department of Commerce from November 1993 to October 1995. From October 1990 to
October 1992, Mr. Garten was a managing director of The Blackstone Group, an
investment banking firm. Prior thereto, Mr. Garten founded and managed The Eliot
Group, a small investment bank, from November 1987 to October 1990, and served
as managing director of Lehman Brothers from January 1979 to November 1987.
 
     Susan C. Schwab became a Director of our company in January 1997. Dr.
Schwab has served as Dean of the School of Public Affairs at the University of
Maryland since August 1995. Dr. Schwab served as Director, Corporate Business
Development at Motorola, Inc. from July 1993 to August 1995. She also served as
Assistant Secretary of Commerce for the U.S. and Foreign Commercial Service from
March 1989 to May 1993.
 
     George J. Stathakis became a Director of our company in September 1996 and
has served as a Senior Advisor to us since December 1994. Mr. Stathakis has been
providing financial, business and management advisory services to numerous
corporations since 1985. He also served as Chairman of the Board and Chief
Executive Officer of Ramtron International Corporation, an advanced technology
semiconductor company, from 1990 to 1994. From 1986 to 1989, he served as
Chairman of the Board and Chief Executive Officer of International Capital
Corporation, a subsidiary of American Express. Prior to 1986, Mr. Stathakis
served thirty-two years with General Electric Corporation in various management
and executive positions. During his service with General Electric Corporation,
Mr. Stathakis founded the General Electric Trading Company and was appointed its
first President and Chief Executive.
 
     John O. Wilson became a Director of our company in January 1997. Mr. Wilson
has served as a Senior Research Fellow at the Berkeley Roundtable on the
International Economy and as Executive Vice President and Chief Economist of SDR
Capital Management, Inc. since January 1999. Mr. Wilson served as Executive Vice
President and Chief Economist at Bank of America from August 1984 to January
1999. He joined Bank of America in June 1975 as Director of Economics-Policy
Research. He served as a faculty member at the University of California at
Berkeley from September 1979 to June 1991, at the University of Connecticut from
September 1974 to June 1975, and at Yale University from January 1967 to
September 1970. Mr. Wilson also served as Director of Regulatory Analysis of the
U.S. Atomic Energy Commission from April 1972 to October 1972, as Director of
Welfare Reform of the Department of Health, Education and Welfare from April
1971 to April 1972, and as Assistant Director of the U.S. Office of Economic
Opportunity from August 1969 to April 1971.
 
     V. Orville Wright became a Director of our company in January 1997. Mr.
Wright served in various positions with MCI Communications Corp., including Vice
Chairman and Co-Chief Executive Officer from 1988 to 1991, Vice Chairman and
Chief Executive Officer from 1985 to 1987, and President and Chief Operating
Officer from 1975 to 1985. Prior to 1975, Mr. Wright served in senior positions
at Xerox Corp. from 1973 to 1975, at Amdahl Corporation from 1971 to 1973, at
RCA from 1969 to 1971, and at IBM from 1949 to 1969.
 
     Lynn A. Kerby joined our company in January 1991 and served as Vice
President of Operations through January 1993, at which time he became our Senior
Vice President-Operations. Mr. Kerby became our Executive Vice
President-Operations in August 1998. Prior to joining us, Mr. Kerby served as
Senior Vice President-Operations of Guy F. Atkinson Company ("Guy F. Atkinson"),
an engineering and construction company, from
 
                                       61
<PAGE>   67
 
1989 to 1990, and served in various other positions within Guy F. Atkinson since
1961. Mr. Kerby served on our company's board of directors from 1984 to 1988 as
a Guy F. Atkinson representative. He obtained a Bachelor of Science Degree in
Civil Engineering and Business from the University of Idaho in 1961. Mr. Kerby
holds a Class A Contractors License in the states of California, Arizona and
Hawaii.
 
     Robert D. Kelly has served as our Senior Vice President-Finance since
January 1998 and Vice President, Finance from April 1994 to January 1998. Mr.
Kelly's responsibilities include all project and corporate finance activities.
From 1992 to 1994, Mr. Kelly served as our Director-Project Finance, and from
1991 to 1992, he served as Project Finance Manager. Prior to joining us, he was
the Marketing Manager of Westinghouse Credit Corporation from 1990 to 1991. From
1989 to 1990, Mr. Kelly was Vice President of Lloyds Bank PLC. From 1982 to
1989, Mr. Kelly was employed in various positions with The Bank of Nova Scotia.
He obtained a Master of Business Administration Degree from Dalhousie
University, Canada in 1980 and a Bachelor of Commerce Degree from Memorial
University, Canada, in 1979.
 
                                       62
<PAGE>   68
 
                             PRINCIPAL STOCKHOLDERS
 
     The following table sets forth certain information known to us regarding
beneficial ownership of our common stock as of February 17, 1999 by (1) each
person known by us to be the beneficial owner of more than five percent of the
outstanding shares of our common stock, (2) each of our directors, (3) certain
of our executive officers and (4) all of our officers and directors as a group.
 
<TABLE>
<CAPTION>
            NAME AND ADDRESS                 NUMBER OF SHARES      PERCENTAGE OF SHARES
           OF BENEFICIAL OWNER             BENEFICIALLY OWNED(1)   BENEFICIALLY OWNED(1)
           -------------------             ---------------------   ---------------------
<S>                                        <C>                     <C>
J. & W. Seligman & Co. Incorporated(2)...        2,188,584                 10.8%
  100 Park Avenue
  New York, NY 10017
Lazard Freres & Co. LLC(3)...............        2,111,808                 10.4%
  30 Rockefeller Plaza
  New York, NY 10020
Wellington Management Company, LLP(4)....        1,995,400                  9.9%
  75 State Street
  Boston, MA 02109
Hartford Capital Appreciation HLS Fund,
  Inc.(5)................................        1,886,500                  9.3%
  200 Hopmeadow Street
  Simsbury, CT 06070
Public Employees Retirement System
  of Ohio................................        1,800,000                  8.9%
  277 East Town Street
  Columbus, OH 43215
Putnam Investments, Inc.(6)..............        1,425,800                  7.0%
  One Post Office Square
  Boston, MA 02109
Osterweis Capital Management, Inc.(7)....        1,130,100                  5.6%
  One Maritime Plaza, Suite 1201
  San Francisco, CA 94111
Peter Cartwright(8)......................          949,155                  4.5%
Ann B. Curtis(9).........................          260,375                  1.3%
Lynn A. Kerby(10)........................          152,023                    *
Robert D. Kelly(11)......................          110,327                    *
Jeffrey E. Garten(12)....................           13,000                    *
Susan C. Schwab(12)......................           13,000                    *
George J. Stathakis(13)..................           42,720                    *
John O. Wilson(12).......................           15,903                    *
V. Orville Wright(12)....................           15,419                    *
All executive officers and directors as a
  group (9 persons)(14)..................        1,571,922                  7.2%
</TABLE>
 
Footnotes appear on the next page.
 
                                       63
<PAGE>   69
 
- ---------------
  * Less than one percent
 
 (1) This table is based in part upon information supplied by Schedules 13G
     filed by principal stockholders with the Securities and Exchange Commission
     (the "Commission"). Beneficial ownership is determined in accordance with
     the rules of the Commission and generally includes voting or investment
     power with respect to securities. Shares of common stock subject to
     options, warrants and convertible notes currently exercisable or
     convertible, or exercisable or convertible within 60 days after a specified
     date, are deemed outstanding for computing the percentage of the person
     holding such options but are not deemed outstanding for computing the
     percentage of any other person. Except as indicated by footnote, and
     subject to community property laws where applicable, the persons named in
     the table have sole voting and investment power with respect to all shares
     of common stock shown as beneficially owned by them. The number of shares
     of common stock outstanding as of February 17, 1999 was 20,253,797.
 
 (2) According to the Schedule 13G filed with the Commission, J. & W. Seligman &
     Co. Incorporated possesses shared voting power over 1,799,000 shares and
     shared investment power over 2,188,584 shares.
 
 (3) According to the Schedule 13G filed with the Commission, Lazard Freres &
     Co. LLC possess sole voting power over 1,649,545 shares and sole investment
     power over 2,111,808 shares.
 
 (4) According to the Schedule 13G filed with the Commission, Wellington
     Management Company, LLP possesses shared voting power over 1,960,400 shares
     and shared investment power over 1,995,400 shares.
 
 (5) According to the Schedule 13G filed with the Commission, Hartford Capital
     Appreciation HLS Fund, Inc. possesses shared voting and investment power
     over 1,886,500 shares.
 
 (6) According to the Schedule 13G filed with the Commission, Putnam
     Investments, Inc. possesses shared voting power over 42,500 shares and
     shared investment power over 1,425,800 shares.
 
 (7) According to the Schedule 13G filed with the Commission, Osterweis Capital
     Management, Inc. possesses sole voting power over 961,550 shares and sole
     investment power over 1,130,100 shares.
 
 (8) Includes options to purchase 943,205 shares of our common stock issuable
     upon the exercise of options outstanding as of January 1, 1999 or within 60
     days thereafter.
 
 (9) Includes options to purchase 260,062 shares of our common stock issuable
     upon the exercise of options outstanding as of January 1, 1999 or within 60
     days thereafter.
 
(10) Includes options to purchase 151,523 shares of our common stock issuable
     upon the exercise of options outstanding as of January 1, 1999 or within 60
     days thereafter.
 
(11) Includes options to purchase 109,327 shares of our common stock issuable
     upon the exercise of options outstanding as of January 1, 1999 or within 60
     days thereafter.
 
(12) Represents shares of our common stock issuable upon exercise of options
     that are exercisable as of January 1, 1999 or will become exercisable
     within 60 days thereafter.
 
(13) Includes options to purchase 39,720 shares of our common stock issuable
     upon the exercise of options outstanding as of January 1, 1999 or within 60
     days thereafter.
 
(14) Includes options to purchase 1,561,159 shares of our common stock issuable
     upon the exercise of options outstanding as of January 1, 1999 or within 60
     days thereafter.
 
                                       64
<PAGE>   70
 
                          DESCRIPTION OF CAPITAL STOCK
 
     Our authorized capital stock consists of 100,000,000 shares of common
stock, $.001 par value, and 10,000,000 shares of preferred stock, $.001 par
value. The following summary is qualified in its entirety by the provisions of
our certificate of incorporation and bylaws, which have been filed as exhibits
to the Registration Statement of which this prospectus constitutes a part.
 
COMMON STOCK
 
     There will be 26,161,581 shares of common stock outstanding upon the
completion of the common stock offering. The holders of common stock are
entitled to one vote per share on all matters to be voted upon by the
stockholders. Subject to preferences that may be applicable to any outstanding
preferred stock, the holders of common stock are entitled to receive ratably
such dividends, if any, as may be declared from time to time by the board of
directors out of funds legally available therefor. See "Dividend Policy." In the
event of our liquidation, dissolution or winding up, the holders of common stock
are entitled to share ratably in all assets remaining after payment of
liabilities, subject to prior liquidation rights of preferred stock, if any,
then outstanding. The common stock has no preemptive or conversion rights or
other subscription rights. There are no redemption or sinking fund provisions
applicable to the common stock. All outstanding shares of common stock to be
outstanding upon the completion of the common stock offering will be fully paid
and non-assessable.
 
PREFERRED STOCK
 
     The board of directors has the authority to issue the preferred stock in
one or more series and to fix the rights, preferences, privileges and
restrictions granted to or imposed upon any wholly unissued shares of
undesignated preferred stock and to fix the number of shares constituting any
series and the designations of such series, without any further vote or action
by the stockholders. The board of directors, without stockholder approval, can
issue preferred stock with voting and conversion rights which could adversely
affect the voting power of the holders of common stock. The issuance of
preferred stock may have the effect of delaying, deferring or preventing a
change in control of our company, or could delay or prevent a transaction that
might otherwise give our stockholders an opportunity to realize a premium over
the then prevailing market price of the common stock. There will be no shares of
preferred stock outstanding upon the completion of the common stock offering.
 
ANTI-TAKEOVER EFFECTS OF PROVISIONS OF THE CERTIFICATE OF INCORPORATION, BYLAWS
AND DELAWARE LAW
 
Certificate of Incorporation and Bylaws
 
     Our certificate of incorporation and bylaws provide that our board of
directors is classified into three classes of Directors serving staggered,
three-year terms. The certificate of incorporation also provides that Directors
may be removed only by the affirmative vote of the holders of two-thirds of the
shares of our capital stock entitled to vote. Any vacancy on the board of
directors may be filled only by vote of the majority of Directors then in
office. Further, the certificate of incorporation provides that any "Business
Combination" (as therein defined) requires the affirmative vote of the holders
of two-thirds of the shares
 
                                       65
<PAGE>   71
 
of our capital stock entitled to vote, voting together as a single class. The
certificate of incorporation also provides that all stockholder actions must be
effected at a duly called meeting and not by a consent in writing. The bylaws
provide that our stockholders may call a special meeting of stockholders only
upon a request of stockholders owning at least 50% of our capital stock. These
provisions of the certificate of incorporation and bylaws could discourage
potential acquisition proposals and could delay or prevent a change in control
of our company. These provisions are intended to enhance the likelihood of
continuity and stability in the composition of the board of directors and in the
policies formulated by the board of directors and to discourage certain types of
transactions that may involve an actual or threatened change of control of our
company. These provisions are designed to reduce our vulnerability to an
unsolicited acquisition proposal. The provisions also are intended to discourage
certain tactics that may be used in proxy fights. However, such provisions could
have the effect of discouraging others from making tender offers for our shares
and, as a consequence, they also may inhibit fluctuations in the market price of
our shares that could result from actual or rumored takeover attempts. Such
provisions also may have the effect of preventing changes in our management.
 
Delaware Anti-Takeover Statute
 
     We are subject to Section 203 of the Delaware General Corporation Law
("Section 203"), which, subject to certain exceptions, prohibits a Delaware
corporation from engaging in any business combination with any interested
stockholder for a period of three years following the date that such stockholder
became an interested stockholder, unless: (1) prior to such date, the board of
directors of the corporation approved either the business combination or the
transaction that resulted in the stockholder becoming an interested stockholder;
(2) upon consummation of the transaction that resulted in the stockholder
becoming an interested stockholder, the interested stockholder owned at least
85% of the voting stock of the corporation outstanding at the time the
transaction commenced, excluding for purposes of determining the number of
shares outstanding those shares owned (x) by persons who are directors and also
officers and (y) by employee stock plans in which employee participants do not
have the right to determine confidentially whether shares held subject to the
plan will be tendered in a tender or exchange offer; or (3) on or subsequent to
such date, the business combination is approved by the board of directors and
authorized at an annual or special meeting of stockholders, and not by written
consent, by the affirmative vote of at least 66 2/3% of the outstanding voting
stock that is not owned by the interested stockholder.
 
     Section 203 defines business combination to include: (1) any merger or
consolidation involving the corporation and the interested stockholder; (2) any
sale, transfer, pledge or other disposition of 10% or more of the assets of the
corporation involving the interested stockholder; (3) subject to certain
exceptions, any transaction that results in the issuance or transfer by the
corporation of any stock of the corporation to the interested stockholder; (4)
any transaction involving the corporation that has the effect of increasing the
proportionate share of the stock of any class or series of the corporation
beneficially owned by the interested stockholder; or (5) the receipt by the
interested stockholder of the benefit of any loans, advances, guarantees,
pledges or other financial benefits provided by or through the corporation. In
general, Section 203 defines an interested stockholder as any entity or person
beneficially owning 15% or more of the outstanding voting stock of the
corporation and any entity or person affiliated with or controlling or
controlled by such entity or person.
 
                                       66
<PAGE>   72
 
                        DESCRIPTION OF THE SENIOR NOTES
 
     Concurrently with the common stock offering, we are offering up to [$500.0]
million aggregate principle amount of senior notes pursuant to the senior note
offering. The following discussion summarizes certain terms of the senior notes
and is qualified in its entirety by reference to the indenture relating to the
senior notes.
 
     The      % Senior Notes Due 2004, the  % Senior Notes Due 2006, the   %
Senior Notes Due 2009 and the   % Senior Notes Due 2011 are to be issued under
separate indentures (together the "Indentures") to be dated as of
                 , 1999 among us and The Bank of New York, as trustee (the
"Trustee").
 
     Each of these notes are senior unsecured obligations of our company.
 
     The      % Senior Notes bear interest at a rate of      % per annum payable
semi-annually on                and                of each year and mature on
          , 2004. The      % Senior Notes bear interest at a rate of      % per
annum payable semi-annually on                and                of each year
and mature on           , 2006. The      % Senior Notes bear interest at a rate
of      % per annum payable semi-annually on                and
of each year and mature on                , 2009. The      % Senior Notes bear
interest at a rate of      % per annum payable semi-annually on
and                of each year and mature on                , 2011. All of
these notes are not subject to redemption prior to maturity.
 
     Upon a Change of Control Triggering Event (as defined in the Indenture),
each holder of these notes will have the right to require us to repurchase such
notes at 101% of the principal amount thereof plus accrued and unpaid interest
to the repurchase date. The Revolving Credit Facility limits our ability to
redeem these notes.
 
     The Indentures contain certain covenants that, among other things, limit
(1) the incurrence of additional debt by us and our subsidiaries, (2) the
payment of dividends on and redemptions of capital stock by us and our
subsidiaries, (3) the use of proceeds from the sale of assets and subsidiary
stock, (4) transactions with affiliates, (5) the incurrence of liens, (6) sale
and leaseback transactions and (7) consolidations, mergers and certain transfers
of assets.
 
                   DESCRIPTION OF CERTAIN OTHER INDEBTEDNESS
 
7 7/8% SENIOR NOTES DUE 2008
 
     On March 31, 1998 and July 24, 1998, we issued $300.0 million and $100.0
million, respectively, aggregate principal amount of 7 7/8% Senior Notes. The
7 7/8% Senior Notes are senior unsecured obligations of our company and rank
equal with our other senior notes, including the senior notes being offered in
the senior note offering.
 
     The 7 7/8% Senior Notes bear interest at a rate of 7 7/8% per annum payable
semi-annually on April 1 and October 1 of each year and mature on April 1, 2008.
The 7 7/8% Senior Notes are not subject to redemption prior to maturity.
 
     Upon a Change of Control Triggering Event (as defined in the 7 7/8%
Indenture), each holder of 7 7/8% Senior Notes will have the right to require us
to repurchase such 7 7/8% Senior Notes at 101% of the principal amount thereof
plus accrued and unpaid
 
                                       67
<PAGE>   73
 
interest to the repurchase date. The Revolving Credit Facility limits our
ability to redeem the 7 7/8% Senior Notes.
 
     Similar to the indentures governing the senior notes being offered pursuant
to the senior note offering (and subject to similar qualifications), the 7 7/8%
Indenture contains certain covenants that, among other things, limit (1) the
incurrence of additional debt by us and our subsidiaries, (2) the payment of
dividends on and redemptions of capital stock by us and our subsidiaries, (3)
the use of proceeds from the sale of assets and subsidiary stock, (4)
transactions with affiliates, (5) the incurrence of liens, (6) sale and
leaseback transactions and (7) consolidations, mergers and certain transfers of
assets.
 
     The foregoing summary describes certain provisions of the 7 7/8% Indenture
and the 7 7/8% Senior Notes, a copy of each of which is available upon request
made to us. The foregoing summary does not purport to be complete and is subject
to and is qualified in its entirety by reference to the 7 7/8% Indenture and the
form of 7 7/8% Senior Notes.
 
8 3/4% SENIOR NOTES DUE 2007
 
     On July 8, 1997 and September 10, 1997, we issued $200.0 million and $75.0
million, respectively, aggregate principal amount of 8 3/4% Senior Notes. The
8 3/4% Senior Notes are senior unsecured obligations of our company and rank
equal with our other senior notes, including the senior notes being offered in
the senior note offering.
 
     The 8 3/4% Senior Notes bear interest at a rate of 8 3/4% per annum payable
semi-annually on January 15 and July 15 of each year and mature on July 15,
2007. The 8 3/4% Senior Notes are redeemable at our option, in whole or in part,
at any time after July 15, 2002 at the various redemption prices set forth in
the 8 3/4% Indenture, plus accrued interest to the date of redemption. In
addition, prior to July 15, 2000, up to $96.3 million of the 8 3/4% Senior Notes
may be redeemed at 108.75% of the principal amount thereof, plus accrued
interest, with the net proceeds of one or more public equity offerings by us.
 
     Upon a Change of Control Triggering Event (as defined in the 8 3/4%
Indenture), each holder of 8 3/4% Senior Notes will have the right to require us
to repurchase such 8 3/4% Senior Notes at 101% of the principal amount thereof
plus accrued and unpaid interest to the repurchase date. The Revolving Credit
Facility limits our ability to redeem the 8 3/4% Senior Notes.
 
     Similar to the indentures governing the senior notes being offered pursuant
to the senior note offering (and subject to similar qualifications), the 8 3/4%
Indenture contains certain covenants that, among other things, limit (1) the
incurrence of additional debt by us and our subsidiaries, (2) the payment of
dividends on and redemptions of capital stock by us and our subsidiaries, (3)
the use of proceeds from the sale of assets and subsidiary stock, (4)
transactions with affiliates, (5) the incurrence of liens, (6) sale and
leaseback transactions and (7) consolidations, mergers and certain transfers of
assets.
 
     The foregoing summary describes certain provisions of the 8 3/4% Indenture
and the 8 3/4% Senior Notes, a copy of each of which is available upon request
made to us. The foregoing summary does not purport to be complete and is subject
to and is qualified in its entirety by reference to the 8 3/4% Indenture and the
form of 8 3/4% Senior Notes.
 
                                       68
<PAGE>   74
 
10 1/2% SENIOR NOTES DUE 2006
 
     On May 16, 1996, we issued $180.0 million aggregate principal amount of
10 1/2% Senior Notes. The 10 1/2% Senior Notes are senior unsecured obligations
of our company and will rank equal with our other senior notes, including the
senior notes being offered in the senior notes offering.
 
     The 10 1/2% Senior Notes bear interest at a rate of 10 1/2% per annum
payable semi-annually on May 15, and November 15 of each year and mature on May
15, 2006. The 10 1/2% Senior Notes are redeemable at our option, in whole or in
part, at any time after May 15, 2001 at the various redemption prices set forth
in the 10 1/2% Indenture, plus accrued interest to the date of redemption. In
addition, prior to May 15, 1999, up to $63.0 million of 10 1/2% Senior Notes may
be redeemed at 110.50% of the principal amount thereof, plus accrued interest,
with the net proceeds of one or more public equity offerings by us.
 
     Upon a Change of Control Triggering Event (as defined in the 10 1/2%
Indenture), each holder of 10 1/2% Senior Notes will have the right to require
us to repurchase such 10 1/2% Senior Notes at 101% of the principal amount
thereof plus accrued and unpaid interest to the repurchase date. The Revolving
Credit Facility limits our ability to redeem the 10 1/2% Senior Notes.
 
     Similar to the indentures governing the senior notes being offered pursuant
to the senior note offering (and subject to similar qualifications), the 10 1/2%
Indenture contains certain covenants that, among other things, limit (1) the
incurrence of additional debt by us and our subsidiaries, (2) the payment of
dividends on and redemptions of capital stock by us and our subsidiaries, (3)
the use of proceeds from the sale of assets and subsidiary stock, (4)
transactions with affiliates, (5) the incurrence of liens, (6) sale and
leaseback transactions and (7) consolidations, mergers and certain transfers of
assets.
 
     The foregoing summary describes certain provisions of the 10 1/2% Indenture
and the 10 1/2% Senior Notes, a copy of each of which is available upon request
made to us. The foregoing summary does not purport to be complete and is subject
to and is qualified in its entirety by reference to the 10 1/2% Indenture and
the form of 10 1/2% Senior Notes.
 
9 1/4% SENIOR NOTES DUE 2004
 
     On February 17, 1994, we issued $105.0 million aggregate principal amount
of 9 1/4% Senior Notes in an underwritten public offering. The 9 1/4% Senior
Notes are senior unsecured obligations of our company and will rank equal with
our other senior notes, including the senior notes being offered in the senior
notes offering.
 
     The 9 1/4% Senior Notes bear interest at a rate of 9 1/4% per annum payable
semi-annually on February l and August l of each year and mature on February 1,
2004. The 9 1/4% Senior Notes are redeemable at our option, in whole or in part,
at any time after February 1, 1999 at the various redemption prices set forth in
the 9 1/4% Indenture, plus accrued interest to the date of redemption. In
addition, we may redeem up to $36.8 million of the 9 1/4% Senior Notes.
 
     Upon a Change of Control Triggering Event (as defined in the 9 1/4%
Indenture), each holder of 9 1/4% Senior Notes will have the right to require us
to repurchase such 9 1/4% Senior Notes at 101% of the principal amount thereof
plus accrued and unpaid
 
                                       69
<PAGE>   75
 
interest to the repurchase date. The Revolving Credit Facility limits our
ability to redeem the 9 1/4% Senior Notes.
 
     Similar to the indentures governing the senior notes being offered pursuant
to the senior note offering (and subject to similar qualifications), the 9 1/4%
Indenture contains certain covenants that, among other things, limit (1) the
incurrence of additional debt by us and our subsidiaries, (2) the payment of
dividends on and redemptions of capital stock by us and our subsidiaries, (3)
the use of proceeds from the sale of assets and subsidiary stock, (4)
transactions with affiliates, (5) the incurrence of liens, (6) sale and
leaseback transactions and (7) consolidations, mergers and certain transfers of
assets.
 
     The foregoing summary describes certain provisions of the 9 1/4% Indenture
and the 9 1/4% Senior Notes, a copy of each of which is available upon request
made to us. The foregoing summary does not purport to be complete and is subject
to and is qualified in its entirety by reference to the 9 1/4% Indenture and the
form of 9 1/4% Senior Notes.
 
OTHER
 
     See "Business -- Description of Facilities" and "Management's Discussion
and Analysis of Financial Condition and Results of Operations" for a description
of our other indebtedness, including the Revolving Credit Facility.
 
                                       70
<PAGE>   76
 
                                  UNDERWRITING
 
     Under the terms and subject to the conditions contained in an underwriting
agreement dated        , 1999, we have agreed to sell to the underwriters named
below, for whom Credit Suisse First Boston Corporation,                and
               are acting as representatives, the following respective numbers
of shares of common stock:
 
<TABLE>
<CAPTION>
                                                               NUMBER
                        UNDERWRITER                           OF SHARES
                        -----------                           ---------
<S>                                                           <C>
Credit Suisse First Boston Corporation......................
 
                                                              ---------
          Total.............................................  6,000,000
                                                              =========
</TABLE>
 
     The underwriting agreement provides that the underwriters are obligated to
purchase all the shares of common stock in the offering if any are purchased,
other than those shares covered by the over-allotment option described below.
The underwriting agreement also provides that if an underwriter defaults the
purchase commitments of non-defaulting underwriters may be increased or the
offering of common stock may be terminated.
 
     We have granted to the underwriters a 30-day option to purchase on a pro
rata basis up to 900,000 additional shares at the initial public offering price
less the underwriting discounts and commissions. The option may be exercised
only to cover any over-allotments of common stock.
 
     The underwriters propose to offer the shares of common stock initially at
the public offering price on the cover page of this prospectus and to selling
group members at that price less a concession of $     per share. The
underwriters and selling group members may allow a discount of $     per share
on sales to other broker/dealers. After the initial public offering, the public
offering price and concession and discount to broker/dealers may be changed by
the representatives.
 
     The following table summarizes the compensation and estimated expenses we
will pay.
 
<TABLE>
<CAPTION>
                                                                TOTAL
                                                   -------------------------------
                                           PER        WITHOUT            WITH
                                          SHARE    OVER-ALLOTMENT   OVER-ALLOTMENT
                                          ------   --------------   --------------
<S>                                       <C>      <C>              <C>
Underwriting Discounts and
  Commissions...........................  $           $             $
Expenses payable by us..................  $           $             $
</TABLE>
 
     We and each of our officers and directors have agreed that we will not
offer, sell, contract to sell, announce our intention to sell, pledge or
otherwise dispose of, directly or indirectly, or file with the Securities and
Exchange Commission a registration statement under the Securities Act of 1933
relating to any additional shares of our common stock or securities convertible
into or exchangeable or exercisable for any of our common stock without the
prior written consent of Credit Suisse First Boston Corporation for a period of
 
                                       71
<PAGE>   77
 
90 days after the date of this prospectus, except in our case issuances pursuant
to the exercise of employee stock options outstanding on the date hereof.
 
     We have agreed to indemnify the underwriters against certain liabilities
under the Securities Act, or contribute to payments which the underwriters may
be required to make in respect thereof.
 
     The representatives, on behalf of the underwriters, may engage in
over-allotments, stabilizing transactions, syndicate covering transactions and
penalty bids in accordance with Regulation M under the Securities Exchange Act
of 1934. Over-allotment involves syndicate sales in excess of the offering size,
which creates a syndicate short position. Stabilizing transactions permit bids
to purchase the underlying security so long as the stabilizing bids do not
exceed a specified maximum. Syndicate covering transactions involve purchases of
the common stock in the open market after the distribution has been completed in
order to cover syndicate short positions. Penalty bids permit the
representatives to reclaim a selling concession from a syndicate member when the
common stock originally sold by such syndicate member are purchased in a
syndicate covering transaction to cover syndicate short positions. Such
stabilizing transactions, syndicate covering transactions and penalty bids may
cause the price of the common stock to be higher than it would otherwise be in
the absence of such transactions. These transactions may be effected on The New
York Stock Exchange or otherwise and, if commenced, may be discontinued at any
time.
 
                          NOTICE TO CANADIAN RESIDENTS
 
RESALE RESTRICTIONS
 
     The distribution of the common stock in Canada is being made only on a
private placement basis exempt from the requirement that we prepare and file a
prospectus with the securities regulatory authorities in each province where
trades of common stock are effected. Accordingly, any resale of the common stock
in Canada must be made in accordance with applicable securities law which will
vary depending on the relevant jurisdiction, and which may require resales to be
made in accordance with available statutory exemptions or pursuant to a
discretionary exemption granted by the applicable Canadian securities regulatory
authority. Purchasers are advised to seek legal advice prior to any resale of
the common stock.
 
REPRESENTATIONS OF PURCHASERS
 
     Each purchaser of common stock in Canada who receives a purchase
confirmation will be deemed to represent to us and the dealer from whom such
purchase confirmation is received that (1) such purchaser is entitled under
applicable provincial securities laws to purchase such common stock without the
benefit of a prospectus qualified under such securities laws, (2) where required
by law, that such purchaser is purchasing as principal and not as agent, and (3)
such purchaser has reviewed the text above under "Resale Restrictions".
 
                                       72
<PAGE>   78
 
RIGHTS OF ACTION (ONTARIO PURCHASERS)
 
     The securities being offered are those of a foreign issuer and Ontario
purchasers will not receive the contractual right of action prescribed by
Section 32 of the Regulation under the Securities Act (Ontario). As a result,
Ontario purchasers must rely on other remedies that may be available, including
common law rights of action for damages or rescission or rights of action under
the civil liability provisions of the U.S. federal securities laws.
 
ENFORCEMENT OF LEGAL RIGHTS
 
     All of the issuer's directors and officers as well as the experts named
herein may be located outside of Canada and, as a result, it may not be possible
for Canadian purchasers to effect service of process within Canada upon the
issuer or such persons. All or a substantial portion of the assets of the issuer
and such persons may be located outside of Canada and, as a result, it may not
be possible to satisfy a judgment against the issuer or such persons in Canada
or to enforce a judgment obtained in Canadian courts against such issuer or
persons outside of Canada.
 
NOTICE TO BRITISH COLUMBIA RESIDENTS
 
     A purchaser of common stock to whom the Securities Act (British Columbia)
applies is advised that such purchaser is required to file with the British
Columbia Securities Commission a report within ten days of the sale of any
common stock acquired by such purchaser pursuant to this offering. Such report
must be in the form attached to British Columbia Securities Commission Blanket
Order BOR #95/17, a copy of which may be obtained from us. Only one such report
must be filed in respect of common stock acquired on the same date and under the
same prospectus exemption.
 
TAXATION AND ELIGIBILITY FOR INVESTMENT
 
     Canadian purchasers of common stock should consult their own legal and tax
advisors with respect to the tax consequences of an investment in the common
stock in their particular circumstances and with respect to the eligibility of
the common stock for investment by the purchaser under relevant Canadian
legislation.
 
                                 LEGAL MATTERS
 
     The validity of the securities offered hereby will be passed upon for us by
Brobeck, Phleger & Harrison LLP, San Francisco, California. The underwriters
have been represented by Skadden, Arps, Slate, Meagher & Flom LLP, New York, New
York.
 
                                       73
<PAGE>   79
 
                                    EXPERTS
 
     The financial statements and schedules incorporated by reference in this
prospectus and elsewhere in the registration statement have been audited by
Arthur Andersen LLP, independent public accountants, as set forth in their
reports. In those reports, that firm states that with respect to a certain
subsidiary its opinion is based on the reports of other independent public
accountants, namely Moss Adams LLP. The financial statements and supporting
schedules referred to above have been included herein in reliance upon the
authority of that firm as experts in giving said reports.
 
     The consolidated financial statements of Sumas Cogeneration Company, L.P.
and Subsidiary as of December 31, 1998 and 1997 and for each of the years ended
December 31, 1998, 1997 and 1996 included in our Annual Report on Form 10-K
filed with the Securities and Exchange Commission on                  , 1999 and
incorporated by reference in this prospectus have been audited by Moss Adams
LLP, independent public accountants, as indicated in their reports with respect
thereto, and are included herein in reliance upon authority of said firm as
experts in giving said reports.
 
                                       74
<PAGE>   80
 
The information in this prospectus is not complete and may be changed. We may
not sell these securities until the registration statement filed with Securities
and Exchange Commission is effective. This prospectus is not an offer to sell
these securities and is not soliciting an offer to buy these securities in any
state where the offer or sale is not permitted.
 
                 SUBJECT TO COMPLETION, DATED FEBRUARY 18, 1999
 
                                  $500,000,000
 
LOGO                          CALPINE CORPORATION
 
                    $                % Senior Notes Due 2004
                    $                % Senior Notes Due 2006
                    $                % Senior Notes Due 2009
                    $                % Senior Notes Due 2011
                               ------------------
 
We will pay interest on the Senior Notes each           and           . The
first interest payment
                      will be made on             , 1999.
 
          We may not redeem the Senior Notes prior to their maturity.
 
Concurrently with this offering of Senior Notes, we are offering 6,000,000
shares of our
                                 common stock.
 
INVESTING IN THE SENIOR NOTES INVOLVES CERTAIN RISKS. SEE "RISK FACTORS" ON PAGE
                                       8.
 
<TABLE>
<CAPTION>
                                                      UNDERWRITING          PROCEEDS TO
                                       PRICE TO         DISCOUNTS             CALPINE
                                      PUBLIC(1)      AND COMMISSIONS      CORPORATION(1)
                                     ------------   -----------------   -------------------
<S>                                  <C>            <C>                 <C>
Per   % Senior Note................      100%             %                    %
     Total.........................  $                $                    $
Per   % Senior Note................      100%             %                    %
     Total.........................  $                $                    $
Per   % Senior Note................      100%             %                    %
     Total.........................  $                $                    $
Per   % Senior Note................      100%             %                    %
     Total.........................  $                $                    $
</TABLE>
 
(1) Plus accrued interest, if any, from              , 1999.
 
     Delivery of the Senior Notes in book entry form only, will be made through
the Depository Trust Company on or about              , 1999, against payment in
immediately available funds.
 
     Neither the Securities and Exchange Commission nor any state securities
commission has approved or disapproved of these securities or determined if this
prospectus is truthful or complete. Any representation to the contrary is a
criminal offense.
 
                           CREDIT SUISSE FIRST BOSTON
 
                      Prospectus dated             , 1999.
<PAGE>   81
 
                      [Depiction of Delta Energy Center.]
  "Delta Energy Center, a proposed 880 megawatt gas-fired facility located in
                            Pittsburg, California."
 
                      [Depiction of Pasadena Power Plant.]
 "Pasadena Power Plant, a 240 megawatt gas-fired facility located in Pasadena,
                                    Texas."
<PAGE>   82
 
                               TABLE OF CONTENTS
 
<TABLE>
<CAPTION>
                                      PAGE
                                      ----
<S>                                   <C>
PROSPECTUS SUMMARY..................    1
RISK FACTORS........................    8
WHERE YOU CAN FIND MORE
  INFORMATION.......................    8
FORWARD-LOOKING STATEMENTS..........    8
USE OF PROCEEDS.....................    8
CAPITALIZATION......................    9
SELECTED CONSOLIDATED FINANCIAL
  DATA..............................   10
PRO FORMA CONSOLIDATED FINANCIAL
  DATA..............................   11
MANAGEMENT'S DISCUSSION AND ANALYSIS
  OF FINANCIAL CONDITION AND RESULTS
  OF OPERATION......................   12
</TABLE>
 
<TABLE>
<CAPTION>
                                      PAGE
                                      ----
<S>                                   <C>
BUSINESS............................   13
MANAGEMENT..........................   14
PRINCIPAL STOCKHOLDERS..............   15
DESCRIPTION OF THE SENIOR NOTES.....   16
DESCRIPTION OF CERTAIN OTHER
  INDEBTEDNESS......................   56
CERTAIN FEDERAL INCOME TAX
  CONSIDERATIONS....................   59
UNDERWRITING........................   63
NOTICE TO CANADIAN RESIDENTS........   64
LEGAL MATTERS.......................   65
EXPERTS.............................   65
</TABLE>
 
                               ------------------
 
     YOU SHOULD RELY ONLY ON THE INFORMATION CONTAINED IN THIS DOCUMENT OR TO
WHICH WE HAVE REFERRED YOU. WE HAVE NOT AUTHORIZED ANYONE TO PROVIDE YOU WITH
INFORMATION THAT IS DIFFERENT. THIS DOCUMENT MAY ONLY BE USED WHERE IT IS LEGAL
TO SELL THESE SECURITIES. THE INFORMATION CONTAINED IN THIS DOCUMENT MAY ONLY BE
ACCURATE ON THE DATE OF THIS DOCUMENT.
 
                                        i
<PAGE>   83
 
                               PROSPECTUS SUMMARY
 
     This summary highlights information contained elsewhere in this prospectus.
This summary is not complete and does not contain all of the information that
you should consider before investing in the Senior Notes. You should carefully
read the entire prospectus, including the risk factors, the financial statements
and the documents incorporated by reference into it. The terms "Calpine," "our
company," "our" and "we," as used in this prospectus, refer to Calpine
Corporation and its consolidated subsidiaries.
 
                                  THE COMPANY
 
     Calpine is a leading independent power company engaged in the development,
acquisition, ownership and operation of power generation facilities and the sale
of electricity predominantly in the United States. We have experienced
significant growth in all aspects of our business over the last five years.
Currently, we own interests in 22 power plants having an aggregate capacity of
2,729 megawatts and have three acquisition transactions pending in which we will
acquire 14 geothermal power plants with an aggregate capacity of 694 megawatts
and certain related steam fields. We also have six gas-fired projects under
construction having an aggregate capacity of 1,784 megawatts and have announced
plans to develop four gas-fired power plants with a total capacity of 2,580
megawatts. Upon completion of pending acquisitions and projects under
construction, we will have interests in 40 power plants having an aggregate
capacity of 5,207 megawatts, of which we will have a net interest in 4,271
megawatts. This represents significant growth from the 342 megawatts of capacity
we had at the end of 1993. Of this total generating capacity, 81% will be
attributable to gas-fired facilities and 19% will be attributable to geothermal
facilities.
 
     As a result of our expansion program, our revenues, cash flow, earnings and
assets have grown significantly over the last five years, as shown in the table
below.
 
<TABLE>
<CAPTION>
                                                              COMPOUND ANNUAL
                                      1993         1998         GROWTH RATE
                                    --------    ----------    ---------------
                                    (DOLLARS IN MILLIONS)
<S>                                 <C>         <C>           <C>
Total Revenue.....................   $ 69.9      $  555.9           51%
EBITDA............................     42.4         255.3           43%
Net Income........................      3.8          45.7           64%
Total Assets......................    302.3       1,728.9           42%
</TABLE>
 
     Since our inception in 1984, we have developed substantial expertise in all
aspects of the development, acquisition and operation of power generation
facilities. We believe that the vertical integration of our extensive
engineering, construction management, operations, fuel management and financing
capabilities provides us with a competitive advantage to successfully implement
our acquisition and development program and has contributed to our significant
growth over the past five years.
 
                                   THE MARKET
 
     The power industry represents the third largest industry in the United
States, with an estimated end-user market of over $250 billion of electricity
sales in 1998 produced by an aggregate base of power generation facilities with
a capacity of approximately 750,000 megawatts. In response to increasing
customer demand for access to low-cost
                                        1
<PAGE>   84
 
electricity and enhanced services, new regulatory initiatives have been and are
continuing to be adopted at both the state and federal level to increase
competition in the domestic power generation industry. The power generation
industry historically has been largely characterized by electric utility
monopolies producing electricity from old, inefficient, high-cost generating
facilities selling to a captive customer base. Industry trends and regulatory
initiatives have transformed the existing market into a more competitive market
where end users purchase electricity from a variety of suppliers, including
non-utility generators, power marketers, public utilities and others.
 
     There is a significant need for additional power generating capacity
throughout the United States, both to satisfy increasing demand, as well as to
replace old and inefficient generating facilities. Due to environmental and
economic considerations, we believe this new capacity will be provided
predominantly by gas-fired facilities. We believe that these market trends will
create substantial opportunities for efficient, low-cost power producers that
can produce and sell energy to customers at competitive rates.
 
     In addition, as a result of a variety of factors, including deregulation of
the power generation market, utilities, independent power producers and
industrial companies are disposing of power generation facilities. To date,
numerous utilities have sold or announced their intentions to sell their power
generation facilities and have focused their resources on the transmission and
distribution business segments. Many independent producers operating a limited
number of power plants are also seeking to dispose of their plants in response
to competitive pressures, and industrial companies are selling their power
plants to redeploy capital in their core businesses.
 
                                    STRATEGY
 
     Our strategy is to continue our rapid growth by capitalizing on the
significant opportunities in the power market, primarily through our active
development and acquisition programs. In pursuing our proven growth strategy, we
utilize our extensive management and technical expertise to implement a fully
integrated approach to the acquisition, development and operation of power
generation facilities. This approach uses our expertise in design, engineering,
procurement, finance, construction management, fuel and resource acquisition,
operations and power marketing, which we believe provide us with a competitive
advantage. The key elements of our strategy are as follows:
 
     - Development and expansion of power plants. We are actively pursuing the
       development and expansion of highly efficient, low-cost, gas-fired power
       plants to replace old and inefficient generating facilities and meet the
       demand for new generation.
 
     - Acquisition of power plants. Our strategy is to acquire power generating
       facilities that meet our stringent criteria, provide significant
       potential for revenue, cash flow and earnings growth and provide the
       opportunity to enhance the operating efficiencies of the plants.
 
     - Enhancement of the performance and efficiency of existing power
       projects. We continually seek to maximize the power generation potential
       of our operating assets and minimize our operating and maintenance
       expenses and fuel costs.
                                        2
<PAGE>   85
 
                              RECENT DEVELOPMENTS
 
     Project Development and Construction. In July 1998, we achieved a key
milestone in our development program by completing the development of our 240
megawatt gas-fired power plant in Pasadena, Texas. The Pasadena Power Plant
serves as a prototype for future development projects. We currently have six
gas-fired projects under construction, representing an additional 1,784
megawatts of capacity. Of these new projects, we are expanding our Pasadena and
Clear Lake facilities by an aggregate of 545 megawatts. In addition, four new
gas-fired power plants, with a total capacity of 1,239 megawatts, are currently
under construction in Dighton, Massachusetts; Tiverton, Rhode Island; Rumford,
Maine; and Westbrook, Maine. We have also announced plans to develop four
additional power generation facilities, totaling an estimated 2,580 megawatts of
electricity, in California, Texas and Arizona.
 
     Pending Acquisitions. We are currently in the process of completing three
acquisitions comprising 14 geothermal power plants with an aggregate capacity of
694 megawatts and certain related steam fields, located in The Geysers,
California. Historically, we have served as the steam supplier for these
facilities, which have been owned and operated by PG&E. We anticipate that these
acquisitions will enable us to consolidate our operations in The Geysers into a
single ownership structure and to integrate the power plant and steam field
operations, allowing us to optimize the efficiency and performance of the
facilities. We believe that these acquisitions will provide us with significant
synergies that utilize our expertise in geothermal power generation and position
us to benefit from the demand for "green" energy in the competitive market.
                                        3
<PAGE>   86
 
                                  THE OFFERING
 
                              SUMMARY OF THE NOTES
 
Securities Offered..............    $       aggregate principal amount of   %
                                    Senior Notes Due 2004;
 
                                    $       aggregate principal amount of   %
                                    Senior Notes Due 2006;
 
                                    $       aggregate principal amount of   %
                                    Senior Notes Due 2009; and
 
                                    $       aggregate principal amount of   %
                                    Senior Notes Due 2011.
 
Maturity........................                 , 2004 in the case of the
                                         % Senior Notes;
                                                 , 2006 in the case of the
                                         % Senior Notes;
                                                 , 2009 in the case of the
                                         % Senior Notes; and
                                                 , 2011 in the case of the
                                         % Senior Notes.
 
Interest Payment Dates..........                   and                of each
                                    year, commencing              , 1999.
 
Redemption......................    We cannot redeem the Senior Notes prior to
                                    maturity.
 
Ranking.........................    The Senior Notes will be our senior
                                    unsecured obligations and will rank equal in
                                    right of payment with all of our other
                                    existing and future senior indebtedness and
                                    senior in right of payment to all of our
                                    subordinated indebtedness. The Senior Notes
                                    will be effectively subordinated to all
                                    liabilities of our subsidiaries, including
                                    trade payables. As of December 31, 1998,
                                    after giving effect to this offering and the
                                    application of the net proceeds therefrom,
                                    the Senior Notes would not be effectively
                                    subordinated to any secured indebtedness and
                                    we would have had $951.8 million of
                                    outstanding indebtedness ranking equal with
                                    the Senior Notes. See "Risk Factors -- We
                                    have substantial indebtedness that we may be
                                    unable to service and that restricts our
                                    activities," "Risk Factors -- Our ability to
                                    service our indebtedness is dependent on the
                                    earnings of our subsidiaries" and
                                    "Description of the Senior
                                    Notes -- Ranking."
 
Change of Control...............    If a change of control triggering event
                                    occurs, we must give holders of the Senior
                                    Notes the opportunity to sell us their
                                    Senior Notes at a purchase price of 101% of
                                    their face amount, plus accrued and unpaid
                                    interest, if any, to the date of purchase.
                                    The term "change of control triggering
                                    event" is
                                        4
<PAGE>   87
 
                                    defined in the "Description of the Senior
                                    Notes" in this Prospectus.
 
Certain Covenants...............    The indentures under which the Senior Notes
                                    will be issued will contain certain
                                    covenants that, among other things, limit
 
                                    - the incurrence of additional debt by us
                                      and our subsidiaries,
 
                                    - the payment of dividends on and
                                      redemptions of capital stock by us and our
                                      subsidiaries,
 
                                    - the use of proceeds from the sale of
                                      assets and subsidiary stock,
 
                                    - transactions with affiliates,
 
                                    - the creation of liens, and
 
                                    - sale leaseback transactions.
 
                                    The indentures will also restrict our
                                    ability to consolidate or merge with or
                                    into, or to transfer all or substantially
                                    all of our assets to, another person.
                                    However, these limitations are subject to a
                                    number of important qualifications and
                                    exceptions. See "Description of the Senior
                                    Notes -- Covenants."
 
Book-Entry; Delivery and Form...    Senior Notes will initially be represented
                                    by one or more Global Notes in definitive,
                                    fully registered form, registered in the
                                    name of, a nominee of The Depositary Trust
                                    Company ("DTC"). See "Description of the
                                    Senior Notes -- Book-Entry System."
 
Use of Proceeds.................    We expect to utilize a portion of the net
                                    proceeds from the offerings as follows: (1)
                                    $119.6 million to refinance indebtedness
                                    relating to the Gilroy Power Plant, (2)
                                    $101.0 million to acquire the steam fields
                                    that service the Sonoma County Power Plants,
                                    (3) $25.0 million to complete the expansion
                                    of the Clear Lake Power Plant and (4)
                                    approximately $400.0 million to finance a
                                    portion of the power generation facilities
                                    currently under construction and the
                                    projects currently under development,
                                    including, but not limited to, the
                                    Westbrook, Sutter, South Point and Magic
                                    Valley power plants. The remaining net
                                    proceeds, if any, will be used for working
                                    capital and general corporate purposes. See
                                    "Use of Proceeds."
                                        5
<PAGE>   88
 
Concurrent Common Stock
  Offering......................    Concurrently with this offering of senior
                                    notes, we are offering (by a separate
                                    prospectus) 6,000,000 shares of our common
                                    stock.
                                        6
<PAGE>   89
 
           SUMMARY CONSOLIDATED HISTORICAL AND OPERATING INFORMATION
 
     The "Summary Consolidated Historical and Operating Information" to be
included in this Prospectus appears in this registration statement as part of
the prospectus for the common stock offering that also is part of this
registration statement.
                                        7
<PAGE>   90
 
                                  RISK FACTORS
 
     The "Risk Factors" section to be included in this prospectus appears in
this registration statement as part of the prospectus for the common stock
offering that also is part of this registration statement.
 
                      WHERE YOU CAN FIND MORE INFORMATION
 
     The "Where you can find more information" section to be included in this
prospectus appears in this registration statement as part of the prospectus for
the common stock offering that also is part of this registration statement.
 
                           FORWARD-LOOKING STATEMENTS
 
     The "Forward-looking statements" section to be included in this Prospectus
appears in this registration statement as part of the prospectus for the common
stock offering that also is part of this registration statement.
 
                                USE OF PROCEEDS
 
     The "Use of Proceeds" section to be included in this prospectus appears in
this registration statement as part of the prospectus for the common stock
offering that also is part of this registration statement.
 
                                        8
<PAGE>   91
 
                                 CAPITALIZATION
 
     The "Capitalization" section to be included in this prospectus appears in
this registration statement as part of the prospectus for the common stock
offering that also is part of this registration statement.
 
                                        9
<PAGE>   92
 
                      SELECTED CONSOLIDATED FINANCIAL DATA
 
     The "Selected Consolidated Financial Data" to be included in this
prospectus appears in this registration statement as part of the prospectus for
the common stock offering that also is part of this registration statement.
 
                                       10
<PAGE>   93
 
                     PRO FORMA CONSOLIDATED FINANCIAL DATA
 
     The "Pro Forma Consolidated Financial Data" to be included in this
prospectus appears in this registration statement as part of the prospectus for
the common stock offering that also is part of this registration statement.
 
                                       11
<PAGE>   94
 
                      MANAGEMENT'S DISCUSSION AND ANALYSIS
                OF FINANCIAL CONDITION AND RESULTS OF OPERATION
 
     The "Management's Discussion and Analysis of Financial Condition and
Results of Operations" to be included in this prospectus appears in this
registration statement as part of the prospectus for the common stock offering
that also is part of this registration statement.
 
                                       12
<PAGE>   95
 
                                    BUSINESS
 
     The "Business" section to be included in this prospectus appears in this
registration statement as part of the prospectus for the common stock offering
that also is part of this registration statement.
 
                                       13
<PAGE>   96
 
                                   MANAGEMENT
 
     The "Management" section to be included in this prospectus appears in this
registration statement as part of the prospectus for the common stock offering
that also is part of this registration statement.
 
                                       14
<PAGE>   97
 
                             PRINCIPAL STOCKHOLDERS
 
     The "Principal Stockholders" section to be included in this prospectus
appears in this registration statement as part of the prospectus for the common
stock offering that also is part of this registration statement.
 
                                       15
<PAGE>   98
 
                        DESCRIPTION OF THE SENIOR NOTES
 
     We will issue the   % Senior Notes due 2004,   % Senior Notes due 2006,   %
Senior Notes due 2009, and   % Senior Notes due 2011, under separate indentures
(each an "Indenture" and together, the "Indentures") between ourselves and The
Bank of New York, as trustee (the "Trustee"). The terms of each of the
Indentures are the same except that the maturity dates of the Senior Notes are
different.
 
     The following description is only a summary of the material provisions of
the Indentures. We urge you to read the Indentures because they, and not this
description, define your rights as holders of the Senior Notes. A copy of the
proposed form of Indenture is available upon request made to us or to the
underwriters.
 
     We have no sinking fund or mandatory redemption obligations with respect to
the Senior Notes.
 
     We are subject to the informational reporting requirements of Sections 13
and 15(d) under the Exchange Act and, in accordance therewith, will file certain
reports and other information with the Commission. See "Where you can find more
information." In addition, if Sections 13 and 15(d) cease to apply to us, we
will covenant in the Indentures to file such reports and information with the
Trustee and the Commission, and mail such reports and information to holders of
the Senior Notes at their registered addresses, for so long as any Senior Notes
remain outstanding.
 
     We conduct substantially all of our operations through our subsidiaries.
Creditors of our subsidiaries, including trade creditors, would have a claim on
our subsidiaries' assets that would be prior to the claims of the holders of the
Senior Notes. See "Risk Factors -- Our ability to service our indebtedness is
dependent on the earnings of our subsidiaries."
 
TERMS OF THE NOTES
 
     The   % Senior Notes are being issued with an aggregate principal amount of
$          and will mature on                  , 2004. The   % Senior Notes are
being issued with an aggregate principal amount of $          and will mature on
                 , 2006. The   % Senior Notes are being issued with an aggregate
principal amount of $          and will mature on                  , 2009. The
  % Senior Notes are being issued with an aggregate principal amount of
$          and will mature on                  , 2011. The Senior Notes will be
issued in fully registered form in denominations of $1,000 and any amount which
is an integral amount multiple of $1,000 in excess thereof.
 
     Interest at the annual rate for the Senior Notes set forth on the cover
page of this prospectus is payable semi-annually on              and
             of each year while the Senior Notes are outstanding, commencing on
                 , 1999 (each, an "Interest Payment Date"), to holders of record
at the close of business on the preceding              and              ,
respectively, and unless other arrangements are made, will be paid by check
mailed to such holders at their registered addresses, as shown on the Senior
Note register. Interest will be computed on the basis of a 360-day year of
twelve months of 30 days each. Interest will begin to accrue on                ,
1999.
 
     Payments of principal of, and premium (if any) on the Senior Notes will be
made against presentation of the Senior Notes at or after the due date for such
payments, at an office maintained by the Trustee for such purpose at The Bank of
New York, 101 Barclay
 
                                       16
<PAGE>   99
 
Street, New York, New York 10286, and the Senior Notes may be presented for
registration of transfer and exchange without service charge, at such office
during normal business hours on any day on which banks in the Borough of
Manhattan, in the City of New York, are open for business.
 
REDEMPTION
 
     The Senior Notes are not subject to redemption prior to maturity.
 
RANKING
 
     The Indebtedness evidenced by the Senior Notes constitutes Senior
Indebtedness of the Company and will rank equal in right of payment with all
existing and future Senior Indebtedness of the Company, including, without
limitation, all obligations under the Bank Credit Agreement (as defined herein),
the Working Capital Credit Agreement (as defined herein), the 7 7/8% Senior
Notes, the 8 3/4% Senior Notes, the 9 1/4% Senior Notes, and the 10 1/2% Senior
Notes. At December 31, 1998, after giving effect to this offering, the common
stock offering and the application of the net proceeds therefrom, we would have
had outstanding approximately $1.5 billion of Senior Indebtedness. We conduct
substantially all of our operations through our subsidiaries. Creditors of our
subsidiaries, including trade creditors, would have a claim on our subsidiaries'
assets that would be prior to the claims of the holders of the Senior Notes. At
December 31, 1998, after giving effect to this offering, the common stock
offering and the application of the proceeds therefrom, our subsidiaries would
not have had any outstanding indebtedness to which the Senior Notes would be
effectively subordinated and we would have had $951.8 million of outstanding
indebtedness ranking equal with the Senior Notes. See "Risk Factors -- Our
ability to service our indebtedness is dependent on the earnings of our
subsidiaries."
 
CERTAIN DEFINITIONS
 
     Set forth below is a summary of certain defined terms used in the
Indentures.
 
     "Acquired Indebtedness" means Indebtedness of a Person existing at the time
at which such Person became a Subsidiary and not incurred in connection with, or
in contemplation of, such Person becoming a Subsidiary. Acquired Indebtedness
shall be deemed to be Incurred on the date the acquired Person becomes a
Subsidiary.
 
     "Additional Assets" means
 
          (i) any property or assets related to the Line of Business which will
     be owned and used by the Company or a Restricted Subsidiary;
 
          (ii) the Capital Stock of a Person that becomes a Restricted
     Subsidiary as a result of the acquisition of such Capital Stock by the
     Company or another Restricted Subsidiary or
 
          (iii) Capital Stock constituting a minority interest in any Person
     that at such time is a Restricted Subsidiary.
 
     "Affiliate" of any specified Person means any other Person, directly or
indirectly, controlling or controlled by or under direct or indirect common
control with such specified Person. For the purposes of this definition,
"control" when used with respect to any Person means the power to direct the
management and policies of such Person, directly or
 
                                       17
<PAGE>   100
 
indirectly, whether through the ownership of voting securities, by contract or
otherwise; and the terms "controlling" and "controlled" have meanings
correlative to the foregoing. For purposes of the provisions described under
"-- Covenants -- Transactions with Affiliates" and "-- Sales of Assets" only,
"Affiliate" shall also mean any beneficial owner of 5% or more of the total
Voting Shares (on a Fully Diluted Basis) of the Company or of rights or warrants
to purchase such stock (whether or not currently exercisable) and any Person who
would be an Affiliate of any such beneficial owner pursuant to the first
sentence hereof. For purposes of the provision described under "-- Covenants --
Limitation on Restricted Payments" only, "Affiliate" shall also mean any Person
of which the Company owns 5% or more of any class of Capital Stock or rights to
acquire 5% or more or any class of Capital Stock and any Person who would be an
Affiliate of any such Person pursuant to the first sentence hereof.
 
     "Asset Sale" means any sale, transfer or other disposition (including by
way of merger, consolidation or sale leaseback transactions, but excluding
(except as provided for in the provisions described in the last paragraph under
"-- Covenants -- Sales of Assets") those permitted by the provisions described
under "-- Covenants -- Merger and Consolidation" and "-- Covenants -- Limitation
on Sale/Leaseback Transactions") in one or a series of transactions by the
Company or any Restricted Subsidiary to any Person other than the Company or any
Wholly Owned Subsidiary, of:
 
          (i) all or any of the Capital Stock of the Company or any Restricted
     Subsidiary,
 
          (ii) all or substantially all of the assets of any operating unit,
     Facility, division or line of business of the Company or any Restricted
     Subsidiary, or
 
          (iii) any other property or assets or rights to acquire property or
     assets of the Company or any Restricted Subsidiary outside of the ordinary
     course of business of the Company or such Restricted Subsidiary.
 
     "Attributable Debt" in respect of a Sale/Leaseback Transaction means, as at
the time of determination, the present value (discounted at the interest rate
borne by the Notes, compounded annually) of the total obligations of the lessee
for rental payments during the remaining term of the lease included in such
Sale/Leaseback Transaction (including any period for which such lease has been
extended).
 
     "Average Life" means, as of the date of determination, with respect to any
Indebtedness or Preferred Stock, the quotient obtained by dividing:
 
          (i) the sum of the products of (A) the numbers of years from the date
     of determination to the dates of each successive scheduled principal
     payment of such Indebtedness or scheduled redemption or similar payment
     with respect to such Indebtedness or Preferred Stock multiplied by (B) the
     amount of such payment, by
 
          (ii) the sum of all such payments.
 
     "Bank Credit Agreement" means the Credit Agreement dated September 25,
1996, between the Company and The Bank of Nova Scotia, as amended, refinanced,
replaced, renewed or extended from time to time.
 
     "Board of Directors" means the Board of Directors of the Company or any
authorized committee thereof.
 
     "Business Day" means each day which is not a Legal Holiday.
 
                                       18
<PAGE>   101
 
     "Capital Stock" means any and all shares, interests, participations or
other equivalents (however designated) of capital stock of a corporation or any
and all equivalent ownership interests in a Person (other than a corporation).
 
     "Capitalized Lease" means, as applied to any Person, any lease of any
property (whether real, personal or mixed) of which the discounted present value
of the rental obligations of such Person as lessee, in conformity with GAAP, is
required to be capitalized on the balance sheet of such Person; the Stated
Maturity thereof shall be the date of the last payment of rent or any other
amount due under such lease prior to the first date upon which such lease may be
terminated by the lessee without payment of a penalty; and "Capitalized Lease
Obligations" means the rental obligations, as aforesaid, under such lease.
 
     "Change of Control" means the occurrence of any of the following events:
 
          (i) any "person" (as such term is used in Sections 13(d) and 14(d) of
     the Exchange Act), other than an underwriter engaged in a firm commitment
     underwriting on behalf of the Company, is or becomes the beneficial owner
     (as such term is used in Rules 13d-3 and 13d-5 under the Exchange Act,
     except that for purposes of this clause (i) a person shall be deemed to
     have beneficial ownership of all shares that such person has the right to
     acquire, whether such right is exercisable immediately or only after the
     passage of time), directly or indirectly, of more than 40% of the total
     Voting Shares of the Company;
 
          (ii) during any period of two consecutive years, individuals who at
     the beginning of such period constituted the Board of Directors (together
     with any new directors whose election by the Board of Directors or whose
     nomination for election by the stockholders was approved by a vote of
     66 2/3% of the directors of the Company then still in office who were
     either directors at the beginning of such period or whose election or
     nomination for election was previously so approved) cease for any reason to
     constitute a majority of the Board of Directors then in office;
 
          (iii) all or substantially all of the Company's and its Restricted
     Subsidiaries' assets are sold, leased, exchanged or otherwise transferred
     to any Person or group of Persons acting in concert; or
 
          (iv) the Company is liquidated or dissolved or adopts a plan of
     liquidation.
 
                                       19
<PAGE>   102
 
     "Change of Control Triggering Event" means:
 
          (i) if a Rating Agency maintains a rating of the Notes at the time a
     Change of Control occurs, the occurrence of a Change of Control and the
     occurrence of a Rating Decline or
 
          (ii) if no Rating Agency maintains a rating of the Notes at the time a
     Change of Control occurs, the occurrence of a Change of Control.
 
     "Code" means the Internal Revenue Code of 1986, as amended.
 
     "Company" means the party named as such in the Indenture until a successor
replaces it pursuant to the terms and conditions of the Indenture and thereafter
means the successor.
 
     "Consolidated Coverage Ratio" as of any date of determination means the
ratio of:
 
          (i) the aggregate amount of EBITDA for the period of the most recent
     four consecutive fiscal quarters to
 
          (ii) the Consolidated Interest Expense (excluding interest capitalized
     in connection with the construction of a new Facility which interest is
     capitalized during the construction of such Facility) for such four fiscal
     quarters;
 
     provided, however, that if the Company or any Restricted Subsidiary has
Incurred any Indebtedness since the beginning of such period that remains
outstanding or if the transaction giving rise to the need to calculate the
Consolidated Coverage Ratio is an Incurrence of Indebtedness, or both, both
EBITDA and Consolidated Interest Expense for such period shall be calculated
after giving effect on a pro forma basis to:
 
          (x) such new Indebtedness as if such Indebtedness had been Incurred on
     the first day of such period and
 
          (y) the repayment, redemption, repurchase, defeasance or discharge of
     any Indebtedness repaid, redeemed, repurchased, defeased or discharged with
     the proceeds of such new Indebtedness as if such repayment, redemption,
     repurchase, defeasance or discharge had been made on the first day of such
     period;
 
     provided, further, that if within the period during which EBITDA or
Consolidated Interest Expense is measured, the Company or any of its Restricted
Subsidiaries shall have made any Asset Sales,
 
          (x) the EBITDA for such period shall be reduced by an amount equal to
     the EBITDA (if positive) directly attributable to the assets or Capital
     Stock which are the subject of such Asset Sales for such period, or
     increased by an amount equal to the EBITDA (if negative), directly
     attributable thereto for such period and
 
          (y) the Consolidated Interest Expense for such period shall be reduced
     by an amount equal to the Consolidated Interest Expense directly
     attributable to any Indebtedness for which neither Company nor any
     Restricted Subsidiary shall continue to be liable as a result of any such
     Asset Sale or repaid, redeemed, defeased, discharged or otherwise retired
     in connection with or with the proceeds of the assets or Capital Stock
     which are the subject of such Asset Sales for such period;
 
                                       20
<PAGE>   103
 
     and provided, further, that if the Company or any Restricted Subsidiary
shall have made any acquisition of assets or Capital Stock (occurring by merger
or otherwise) since the beginning of such period (including any acquisition of
assets or Capital Stock occurring in connection with a transaction causing a
calculation to be made hereunder) the EBITDA and Consolidated Interest Expense
for such period shall be calculated, after giving pro forma effect thereto (and
without regard to clause (iv) of the proviso to the definition of "Consolidated
Net Income"), as if such acquisition of assets or Capital Stock took place on
the first day of such period. For all purposes of this definition, if the date
of determination occurs prior to the completion of the first four full fiscal
quarters following the Issue Date, then "EBITDA" and "Consolidated Interest
Expense" shall be calculated after giving effect on a pro forma basis to the
Offering as if the Offering occurred on the first day of the four full fiscal
quarters that were completed preceding such date of determination.
 
     "Consolidated Current Liabilities" as of the date of determination, means
the aggregate amount of liabilities of the Company and its Consolidated
Restricted Subsidiaries which may properly be classified as current liabilities
(including taxes accrued as estimated), after eliminating:
 
          (i) all inter-company items between the Company and any Consolidated
     Subsidiary and
 
          (ii) all current maturities of long-term Indebtedness, all as
     determined in accordance with GAAP.
 
     "Consolidated Income Tax Expense" means, for any period, as applied to the
Company, the provision for local, state, federal or foreign income taxes on a
Consolidated basis for such period determined in accordance with GAAP.
 
     "Consolidated Interest Expense" means, for any period, as applied to the
Company, the sum of:
 
          (a) the total interest expense of the Company and its Consolidated
     Restricted Subsidiaries for such period as determined in accordance with
     GAAP, including, without limitation,
 
             (i) amortization of debt issuance costs or of original issue
        discount on any Indebtedness and the interest portion of any deferred
        payment obligation, calculated in accordance with the effective interest
        method of accounting,
 
             (ii) accrued interest,
 
             (iii) noncash interest payments,
 
             (iv) commissions, discounts and other fees and charges owed with
        respect to letters of credit and bankers' acceptance financing,
 
             (v) interest actually paid by the Company or any such Subsidiary
        under any guarantee of Indebtedness or other obligation of any other
        Person and
 
             (vi) net costs associated with Interest Rate Agreements (including
        amortization of discounts) and Currency Agreements, plus
 
                                       21
<PAGE>   104
 
          (b) all but the principal component of rentals in respect of
     Capitalized Lease Obligations paid, accrued, or scheduled to be paid or
     accrued by the Company or its Consolidated Restricted Subsidiaries, plus
 
          (c) one-third of all Operating Lease Obligations paid, accrued and/or
     scheduled to be paid by the Company and its Consolidated Restricted
     Subsidiaries, plus
 
          (d) capitalized interest, plus
 
          (e) dividends paid in respect of Preferred Stock of the Company or any
     Restricted Subsidiary held by Persons other than the Company or a Wholly
     Owned Subsidiary, plus
 
          (f) cash contributions to any employee stock ownership plan to the
     extent such contributions are used by such employee stock ownership plan to
     pay interest or fees to any person (other than the Company or a Restricted
     Subsidiary) in connection with loans incurred by such employee stock
     ownership plan to purchase Capital Stock of the Company.
 
     "Consolidated Net Income (Loss)" means, for any period, as applied to the
Company, the Consolidated net income (loss) of the Company and its Consolidated
Restricted Subsidiaries for such period, determined in accordance with GAAP,
adjusted by excluding (without duplication), to the extent included in such net
income (loss), the following:
 
          (i) all extraordinary gains or losses;
 
          (ii) any net income of any Person if such Person is not a Domestic
     Subsidiary, except that
 
             (A) the Company's equity in the net income of any such Person for
        such period shall be included in Consolidated Net Income (Loss) up to
        the aggregate amount of cash actually distributed by such Person during
        such period to the Company or a Restricted Subsidiary as a dividend or
        other distribution and
 
             (B) the equity of the Company or a Restricted Subsidiary in a net
        loss of any such Person for such period shall be included in determining
        Consolidated Net Income (Loss);
 
          (iii) the net income of any Restricted Subsidiary to the extent that
     the declaration or payment of dividends or similar distributions by such
     Restricted Subsidiary of such income is not at the time thereof permitted,
     directly or indirectly, by operation of the terms of its charter or bylaws
     or any agreement, instrument, judgment, decree, order, statute, rule or
     governmental regulation applicable to such Restricted Subsidiary or its
     stockholders;
 
          (iv) any net income (or loss) of any Person combined with the Company
     or any of its Restricted Subsidiaries on a "pooling of interests" basis
     attributable to any period prior to the date of such combination;
 
          (v) any gain (but not loss) realized upon the sale or other
     disposition of any property, plant or equipment of the Company or its
     Restricted Subsidiaries (including pursuant to any sale-and-leaseback
     arrangement) which is not sold or otherwise disposed of in the ordinary
     course of business and any gain (but not loss) realized upon the sale or
     other disposition by the Company or any Restricted Subsidiary of any
 
                                       22
<PAGE>   105
 
     Capital Stock of any Person, provided that losses shall be included on an
     after-tax basis; and
 
          (vi) the cumulative effect of a change in accounting principles; and
     further adjusted by subtracting from such net income the tax liability of
     any parent of the Company to the extent of payments made to such parent by
     the Company pursuant to any tax sharing agreement or other arrangement for
     such period.
 
     "Consolidated Net Tangible Assets" means, as of any date of determination,
as applied to the Company, the total amount of assets (less accumulated
depreciation or amortization, allowances for doubtful receivables, other
applicable reserves and other properly deductible items) which would appear on a
Consolidated balance sheet of the Company and its Consolidated Restricted
Subsidiaries, determined on a Consolidated basis in accordance with GAAP, and
after giving effect to purchase accounting and after deducting therefrom, to the
extent otherwise included, the amounts of:
 
          (i) Consolidated Current Liabilities;
 
          (ii) minority interests in Consolidated Subsidiaries held by Persons
     other than the Company or a Restricted Subsidiary;
 
          (iii) excess of cost over fair value of assets of businesses acquired,
     as determined in good faith by the Board of Directors;
 
          (iv) any revaluation or other write-up in value of assets subsequent
     to December 31, 1993 as a result of a change in the method of valuation in
     accordance with GAAP;
 
          (v) unamortized debt discount and expenses and other unamortized
     deferred charges, goodwill, patents, trademarks, service marks, trade
     names, copyrights, licenses, organization or developmental expenses and
     other intangible items;
 
          (vi) treasury stock; and
 
          (vii) any cash set apart and held in a sinking or other analogous fund
     established for the purpose of redemption or other retirement of Capital
     Stock to the extent such obligation is not reflected in Consolidated
     Current Liabilities.
 
     "Consolidated Net Worth" means, at any date of determination, as applied to
the Company, stockholders' equity as set forth on the most recently available
Consolidated balance sheet of the Company and its Consolidated Restricted
Subsidiaries (which shall be as of a date no more than 60 days prior to the date
of such computation), less any amounts attributable to Redeemable Stock or
Exchangeable Stock, the cost of treasury stock and the principal amount of any
promissory notes receivable from the sale of Capital Stock of the Company or any
Subsidiary.
 
     "Consolidation" means, with respect to any Person, the consolidation of
accounts of such Person and each of its subsidiaries if and to the extent the
accounts of such Person and such subsidiaries are consolidated in accordance
with GAAP. The term "Consolidated" shall have a correlative meaning.
 
                                       23
<PAGE>   106
 
     "Controlled Non-Subsidiary Investment" means any Investment of the type
specified in clause (iv) of the first sentence under
"-- Covenants -- Limitations on Restricted Payments" which is made by the
Company or its Restricted Subsidiaries in an Affiliate other than a Subsidiary;
provided that:
 
          (i) at the time such Investment is made, no Default or Event of
     Default shall have occurred and be continuing (or would result therefrom);
 
          (ii) after giving effect to the Investment and to the Incurrence of
     any Indebtedness in connection therewith on a pro forma basis, the
     Consolidated Coverage Ratio is at least 1.75:1;
 
          (iii) after giving effect to the Investment, the aggregate Investment
     made by the Company and its Subsidiaries in Controlled Non-Subsidiary
     Investments does not exceed $100,000,000;
 
          (iv) the Person in which the Investment is made is engaged only in the
     business described under "-- Covenants -- Limitation on Changes in the
     Nature of Business" including Unrelated Businesses to the extent permitted
     under "-- Covenants -- Limitations on Changes in the Nature of the
     Business;"
 
          (v) the Company, directly or through its Restricted Subsidiaries is
     entitled to (A) in the case of an Investment in Capital Stock, receive
     dividends or other distributions on its Investment at the same time as or
     prior to, and on a basis pro rata with, any other holder or holders of
     Capital Stock of such Person and (B) in the case of an Investment other
     than in Capital Stock, receive interest thereon at a rate per annum not
     less than the rate on the Notes and, on the liquidation or dissolution of
     such Person, receive repayment of the principal thereof prior to the
     payment of any dividends or distributions on Capital Stock of such Person;
 
          (vi) the Company directly or through its Restricted Subsidiaries,
     either (x) controls, under an operating and management agreement or
     otherwise, the day to day management and operation of such Person and any
     Facility of the Person in which the Investment is made or (y) has
     significant influence over the management and operation of such Person and
     any Facility of such Person in all material respects (significant influence
     to include the right to control or veto any material act or decision) in
     connection with such management or operation; and
 
          (vii) any encumbrances or restrictions on the ability of the Person in
     which the Investment is made to make the payments, distributions, losses,
     advances or transfers referred to in clauses (i) through (iii) under
     "-- Covenants -- Limitations on Payment Restrictions Affecting
     Subsidiaries" in the written opinion of the President or Chief Financial
     Officer of the Company (x) is required in order to obtain necessary
     financing, (y) is customary for such financings and (z) applies only to the
     assets of or revenues of the Person in whom the Investment is made.
 
     "Currency Agreement" means any foreign exchange contract, currency swap
agreement or other similar agreement or arrangement designed to protect the
Company or any Restricted Subsidiary against fluctuations in currency values to
or under which the Company or any Restricted Subsidiary is a party or a
beneficiary on the Issue Date or becomes a party or beneficiary thereafter.
 
     "Default" means any event which is, or after notice or passage of time or
both would be, an Event of Default.
 
                                       24
<PAGE>   107
 
     "Defaulted Interest" means any interest on any Note which is payable, but
is not punctually paid or duly provided for on any Interest Payment Date.
 
     "Domestic Subsidiary" means a Restricted Subsidiary that is not a Foreign
Subsidiary.
 
     "EBITDA" means, for any period, as applied to the Company, the sum of
Consolidated Net Income (Loss) (but without giving effect to adjustments,
accruals, deductions or entries resulting from purchase accounting,
extraordinary losses or gains and any gains or losses from any Asset Sales),
plus the following to the extent included in calculating Consolidated Net Income
(Loss):
 
          (a) Consolidated Income Tax Expense,
 
          (b) Consolidated Interest Expense,
 
          (c) depreciation expense,
 
          (d) amortization expense and
 
          (e) all other non-cash items reducing Consolidated Net Income, less
     all non-cash items increasing Consolidated Net Income, in each case for
     such period;
 
     provided that, if the Company has any Subsidiary that is not a Wholly Owned
Subsidiary, EBITDA shall be reduced (to the extent not otherwise reduced by
GAAP) by an amount equal to:
 
             (A) the consolidated net income (loss) of such Subsidiary (to the
        extent included in Consolidated Net Income (Loss)) multiplied by
 
             (B) the quotient of (1) the number of shares of outstanding common
        stock of such Subsidiary not owned on the last day of such period by the
        Company or any Wholly Owned Subsidiary of the Company divided by (2) the
        total number of shares of outstanding common stock of such Subsidiary on
        the last day of such period.
 
     "Exchangeable Stock" means any Capital Stock which by its terms is
exchangeable or convertible at the option of any Person other than the Company
into another security (other than Capital Stock of the Company which is neither
Exchangeable Stock nor Redeemable Stock).
 
     "Facility" means a power generation facility or energy producing facility,
including any related steam fields or gas reserves.
 
     "Foreign Asset Sale" means an Asset Sale in respect of the Capital Stock or
assets of a Foreign Subsidiary or a Restricted Subsidiary of the type described
in Section 936 of the Code to the extent that the proceeds of such Asset Sale
are received by a Person subject in respect of such proceeds to the tax laws of
a jurisdiction other than the United States of America or any State thereof or
the District of Columbia.
 
     "Foreign Subsidiary" means a Restricted Subsidiary that is incorporated in
a jurisdiction other than the United States of America or a State thereof or the
District of Columbia.
 
     "Fully Diluted Basis" means after giving effect to the exercise of any
outstanding options, warrants or rights to purchase Voting Shares and the
conversion or exchange of any securities convertible into or exchangeable for
Voting Shares.
 
                                       25
<PAGE>   108
 
     "GAAP" means generally accepted accounting principles in the United States
of America as in effect and, to the extent optional, adopted by the Company on
the Issue Date, consistently applied, including, without limitation, those set
forth in the opinions and pronouncements of the Accounting Principles Board of
the American Institute of Certified Public Accountants and statements and
pronouncements of the Financial Accounting Standards Board.
 
     "Guarantee" means, as applied to any obligation, contingent or otherwise,
of any Person:
 
          (i) a guarantee, direct or indirect, in any manner, of any part or all
     of such obligation (other than by endorsement of negotiable instruments for
     collection in the ordinary course of business) and
 
          (ii) an agreement, direct or indirect, contingent or otherwise, the
     practical effect of which is to insure in any way the payment or
     performance (or payment of damages in the event of nonperformance) of any
     part or all of such obligation, including the payment of amounts drawn down
     under letters of credit.
 
     "Holder" or "Securityholder" means the Person in whose name a Note is
registered on the Registrar's books.
 
     "Incur" means, as applied to any obligation, to create, incur, issue,
assume, guarantee or in any other manner become liable with respect to,
contingently or otherwise, such obligation, and "Incurred," "Incurrence" and
"Incurring" shall each have a correlative meaning; provided, however, that any
Indebtedness or Capital Stock of a Person existing at the time such Person
becomes (after the Issue Date) a Subsidiary (whether by merger, consolidation,
acquisition or otherwise) shall be deemed to be Incurred by such Subsidiary at
the time it becomes a Subsidiary; and provided, further, that any amendment,
modification or waiver of any provision of any document pursuant to which
Indebtedness was previously Incurred shall not be deemed to be an Incurrence of
Indebtedness as long as
 
          (i) such amendment, modification or waiver does not:
 
             (A) increase the principal or premium thereof or interest rate
        thereon,
 
             (B) change to an earlier date the Stated Maturity thereof or the
        date of any scheduled or required principal payment thereon or the time
        or circumstances under which such Indebtedness may or shall be redeemed,
 
             (C) if such Indebtedness is contractually subordinated in right of
        payment to the Securities, modify or affect, in any manner adverse to
        the Holders, such subordination,
 
             (D) if the Company is the obligor thereon, provide that a
        Restricted Subsidiary shall be an obligor,
 
             (E) if such Indebtedness is Non-Recourse Debt, cause such
        Indebtedness to no longer constitute Non-Recourse Debt or
 
             (F) violate, or cause the Indebtedness to violate, the provisions
        described under "-- Covenants -- Limitation on Payment Restrictions
        Affecting Subsidiaries" and "-- Limitation on Liens" and
 
                                       26
<PAGE>   109
 
          (ii) such Indebtedness would, after giving effect to such amendment,
     modification or waiver as if it were an Incurrence, comply with clause (i)
     of the first proviso to the definition of "Refinancing Indebtedness."
 
          "Indebtedness" of any Person means, without duplication,
 
          (i) the principal of and premium (if any such premium is then due and
     owing) in respect of:
 
             (A) indebtedness of such Person for money borrowed and
 
             (B) indebtedness evidenced by notes, debentures, bonds or other
        similar instruments for the payment of which such Person is responsible
        or liable;
 
          (ii) all Capitalized Lease Obligations of such Person;
 
          (iii) all obligations of such Person Incurred as the deferred purchase
     price of property, all conditional sale obligations of such Person and all
     obligations of such Person under any title retention agreement;
 
          (iv) all obligations of such Person for the reimbursement of any
     obligor on any letter of credit, banker's acceptance or similar credit
     transaction (other than obligations with respect to letters of credit
     securing obligations (other than obligations described in (i) through (iii)
     above) entered into in the ordinary course of business of such Person to
     the extent such letters of credit are not drawn upon or, if and to the
     extent drawn upon, such drawing is reimbursed no later than the tenth
     Business Day following receipt by such Person of a demand for reimbursement
     following payment on the letter of credit);
 
          (v) Redeemable Stock of such Person and, in the case of any
     Subsidiary, any other Preferred Stock, in either case valued at, in the
     case of Redeemable Stock, the greater of its voluntary or involuntary
     maximum fixed repurchase price exclusive of accrued and unpaid dividends
     or, in the case of Preferred Stock that is not Redeemable Stock, its
     liquidation preference exclusive of accrued and unpaid dividends;
 
          (vi) contractual obligations to repurchase goods sold or distributed;
 
          (vii) all obligations of such Person in respect of Interest Rate
     Agreements and Currency Agreements;
 
          (viii) all obligations of the type referred to in clauses (i) through
     (vii) of other Persons and all dividends of other Persons for the payment
     of which, in either case, such Person is responsible or liable, directly or
     indirectly, as obligor, guarantor or otherwise, including by means of any
     guarantee; and
 
          (ix) all obligations of the type referred to in clauses (i) through
     (viii) of other Persons secured by any Lien on any property or asset of
     such Person (whether or not such obligation is assumed by such Person), the
     amount of such obligation being deemed to be the lesser of the value of
     such property or assets or the amount of the obligation so secured;
     provided, however, that Indebtedness shall not include trade accounts
     payable arising in the ordinary course of business.
 
     For purposes hereof, the "maximum fixed repurchase price" of any Redeemable
Stock which does not have a fixed repurchase price shall be calculated in
accordance with the
 
                                       27
<PAGE>   110
 
terms of such Redeemable Stock as if such Redeemable Stock were purchased on any
date on which Indebtedness shall be required to be determined pursuant to the
Indenture, and if such price is based upon, or measured by, the fair market
value of such Redeemable Stock, such fair market value to be determined in good
faith by the Board of Directors. The amount of Indebtedness of any Person at any
date shall be, with respect to unconditional obligations, the outstanding
balance at such date of all such obligations as described above and, with
respect to any contingent obligations (other than pursuant to clause (vi) above,
which shall be included to the extent reflected on the balance sheet of such
Person in accordance with GAAP) at such date, the maximum liability determined
by such Person's board of directors, in good faith, as, in light of the facts
and circumstances existing at the time, reasonably likely to be Incurred upon
the occurrence of the contingency giving rise to such obligation.
 
     "Interest Payment Date" means the stated maturity of an installment of
interest on the Notes.
 
     "Interest Rate Agreement" means any interest rate protection agreement,
interest rate future agreement, interest rate option agreement, interest rate
swap agreement, interest rate cap agreement, interest rate collar agreement,
interest rate hedge agreement or other similar agreement or arrangement designed
to protect against fluctuations in interest rates to or under which the Company
or any of its Restricted Subsidiaries is a party or beneficiary on the Issue
Date or becomes a party or beneficiary thereunder.
 
     "Investment" means, with respect to any Person, any direct or indirect
advance, loan or other extension of credit or capital contribution to (by means
of any transfer of cash or other property to others or any payment for property
or services for the account or use of others), or any other investment in any
other Person, or any purchase or acquisition by such Person of any Capital
Stock, bonds, notes, debentures or other securities or assets issued or owned by
any other Person (whether by merger, consolidation, amalgamation, sale of assets
or otherwise). For purposes of the definition of "Unrestricted Subsidiary" and
the provisions set forth under "-- Covenants -- Limitation on Restricted
Payments,"
 
          (i) "Investment" shall include the portion (proportionate to the
     Company's equity interest in such Subsidiary) of the fair market value of
     the net assets of any Restricted Subsidiary at the time that such
     Restricted Subsidiary is designated an Unrestricted Subsidiary and shall
     exclude the fair market value of the net assets of any Unrestricted
     Subsidiary at the time that such Unrestricted Subsidiary is designated a
     Restricted Subsidiary and
 
          (ii) any property transferred to or from an Unrestricted Subsidiary
     shall be valued at its fair market value at the time of such transfer, in
     each case as determined by the Board of Directors in good faith. For
     purposes of determining the aggregate amount of Investments in Controlled
     Non-Subsidiary Investments, the amount of such Investments shall be reduced
     by an amount equal to the net payments of interest on Indebtedness,
     dividends, repayments of interest on Indebtedness, dividends, repayments of
     loans or advances, or other transfers of assets, in each case to the
     Company or any Restricted Subsidiary from any Person in whom a Controlled
     Non-Subsidiary Investment has been made, not to exceed in the case of any
     Controlled Non-Subsidiary Investment the amount of Investments previously
     made by the Company or any Restricted Subsidiary in such Person.
 
                                       28
<PAGE>   111
 
     "Investment Grade" means, with respect to the Notes, a rating of Baa3 or
higher by Moody's together with a rating of BBB -- or higher by S&P, provided
that neither of such entities shall have announced or informed the Company that
it is reviewing the rating of the Notes in light of downgrading the rating
thereof.
 
     "Issue Date" means the date on which the Notes are originally issued under
the Indenture.
 
     "Lien" means any mortgage, lien, pledge, charge, or other security interest
or encumbrance of any kind (including any conditional sale or other title
retention agreement and any lease in the nature thereof).
 
     "Line of Business" means the ownership, acquisition, development,
construction, improvement and operation of Facilities.
 
     "Moody's" means Moody's Investors Service, Inc. and its successors.
 
     "Net Available Cash" means, with respect to any Asset Sale, the cash or
cash equivalent payments received by the Company or a Subsidiary in connection
with such Asset Sale (including any cash received by way of deferred payment of
principal pursuant to a note or installment receivable or otherwise, but only as
or when received and also including the proceeds of other property received when
converted to cash or cash equivalents) net of the sum of, without duplication:
 
          (i) all reasonable legal, title and recording tax expenses, reasonable
     commissions, and other reasonable fees and expenses incurred directly
     relating to such Asset Sale,
 
          (ii) all local, state, federal and foreign taxes required to be paid
     or accrued as a liability by the Company or any of its Restricted
     Subsidiaries as a consequence of such Asset Sale,
 
          (iii) payments made to repay Indebtedness which is secured by any
     assets subject to such Asset Sale in accordance with the terms of any Lien
     upon or other security agreement of any kind with respect to such assets,
     or which must by its terms, or by applicable law, be repaid out of the
     proceeds from such Asset Sale and
 
          (iv) all distributions required by any contract entered into other
     than in contemplation of such Asset Sale to be paid to any holder of a
     minority equity interest in such Restricted Subsidiary as a result of such
     Asset Sale, so long as such distributions do not exceed such minority
     holder's pro rata portion (based on such minority holder's proportionate
     equity interest) of the cash or cash equivalent payments described above,
     net of the amounts set forth in clauses (i) - (iii) above.
 
     "Net Cash Proceeds" means, with respect to any issuance or sale of Capital
Stock by any Person, the cash proceeds to such Person of such issuance or sale
net of attorneys' fees, accountants' fees, underwriters' or placement agents'
fees, discounts or commissions and brokerage, consultancy and other fees
actually incurred by such Person in connection with such issuance or sale and
net of taxes paid or payable by such Person as a result thereof.
 
     "Non-Convertible Capital Stock" means, with respect to any corporation, any
Capital Stock of such corporation which is not convertible into another security
other than non-convertible common stock of such corporation; provided, however,
that Non-Convertible Capital Stock shall not include any Redeemable Stock or
Exchangeable Stock.
 
                                       29
<PAGE>   112
 
     "Non-Recourse Debt" means Indebtedness of the Company or any Restricted
Subsidiary that is Incurred to acquire, construct or develop a Facility provided
that such Indebtedness is without recourse to the Company or any Restricted
Subsidiary or to any assets of the Company or any such Restricted Subsidiary
other than such Facility and the income from and proceeds of such Facility.
 
     "Notes" means, with respect to a particular Indenture, the Senior Notes
issued under that Indenture.
 
     "Offering" means the offering and sale of the Notes.
 
     "Officers' Certificate" means a certificate signed by two officers, one of
whom must be the President, the Treasurer or a Vice President of the Company.
Each Officers' Certificate (other than certificates provided pursuant to TIA
Section 314(a)(4)) shall include the statements provided for in TIA Section
314(e).
 
     "Operating Lease Obligations" means any obligation of the Company and its
Restricted Subsidiaries on a Consolidated basis incurred or assumed under or in
connection with any lease of real or personal property which, in accordance with
GAAP, is not required to be classified and accounted for as a capital lease.
 
     "Opinion of Counsel" means a written opinion from legal counsel who is
acceptable to the Trustee. The counsel, if so acceptable, may be an employee of
or counsel to the Company or the Trustee. Each such Opinion of Counsel shall
include the statements provided for in TIA Section 314(e).
 
     "Person" means any individual, corporation, partnership, joint venture,
association, joint-stock company, trust, unincorporated organization, government
or any agency or political subdivision thereof or any other entity.
 
     "Preferred Stock," as applied to the Capital Stock of any corporation,
means Capital Stock of any class or classes (however designated) which is
preferred as to the payment of dividends, or as to the distribution of assets
upon any voluntary or involuntary liquidation or dissolution of such
corporation, over shares of Capital Stock of any other class of such
corporation.
 
     "Principal" of a Note means the principal of the Note plus, if applicable,
the premium on the Note.
 
     "PUHCA" means the Public Utility Holding Company Act of 1935, as amended.
 
     "PURPA" means the Public Utility Regulatory Policies Act of 1978, as
amended.
 
     "Rating Agencies" means S&P and Moody's.
 
     "Rating Category" means:
 
          (i) with respect to S&P, any of the following categories: AAA, AA, A,
     BBB, BB, B, CCC, CC, C and D (or equivalent successor categories) and
 
          (ii) with respect to Moody's, any of the following categories: Aaa,
     Aa, A, Baa, Ba, B, Caa, Ca, C and D (or equivalent successor categories).
 
     In determining whether the rating of the Notes has decreased by one or more
gradations, gradations within Rating Categories (+ and - for S&P; 1, 2 and 3 for
 
                                       30
<PAGE>   113
 
Moody's) shall be taken into account (e.g., with respect to S&P, a decline in a
rating from BB + to BB, as well as from BB - to B +, will constitute a decrease
of one gradation).
 
     "Rating Decline" means the occurrence of (i) or (ii) below on, or within 90
days after, the earliest of (A) the Company having become aware that a Change of
Control has occurred, (B) the date of public notice of the occurrence of a
Change of Control or (C) the date of public notice of the intention by the
Company to approve, recommend or enter into, any transaction which, if
consummated, would result in a Change of Control (which period shall be extended
so long as the rating of the Notes is under publicly announced consideration or
possible downgrade by either of the Rating Agencies),
 
          (i) a decrease of the rating of the Notes by either Rating Agency by
     one or more rating gradations or
 
          (ii) the Company shall fail to promptly advise the Rating Agencies, in
     writing, of such occurrence or any subsequent material developments or
     shall fail to use its best efforts to obtain, from at least one Rating
     Agency, a written, publicly announced affirmation of its rating of the
     Notes, stating that it is not downgrading, and is not considering
     downgrading, the Notes.
 
     "Redeemable Stock" means any class or series of Capital Stock of any Person
that:
 
          (a) by its terms, by the terms of any security into which it is
     convertible or exchangeable or otherwise is, or upon the happening of an
     event or passage of time would be, required to be redeemed (in whole or in
     part) on or prior to the first anniversary of the Stated Maturity of the
     Notes,
 
          (b) is redeemable at the option of the holder thereof at any time on
     or prior to the first anniversary of the Stated Maturity of the Notes
     (other than on a Change of Control or Asset Sale, provided that such Change
     of Control or Asset Sale shall not yet have occurred) or
 
          (c) is convertible into or exchangeable for Capital Stock referred to
     in clause (a) or clause (b) above or debt securities at any time prior to
     the first anniversary of the Stated Maturity of the Notes.
 
     "Refinancing Indebtedness" means Indebtedness that refunds, refinances,
replaces, renews, repays or extends (including pursuant to any defeasance or
discharge mechanism) (collectively, "refinances," and "refinanced" shall have a
correlative meaning) any Indebtedness of the Company or a Restricted Subsidiary
existing on the Issue Date or Incurred in compliance with the Indenture
(including Indebtedness of the Company that refinances Indebtedness of any
Restricted Subsidiary and Indebtedness of any Restricted Subsidiary that
refinances Indebtedness of another Restricted Subsidiary) including Indebtedness
that refinances Refinancing Indebtedness; provided, however, that:
 
          (i) if the Indebtedness being refinanced is contractually subordinated
     in right of payment to the Notes, the Refinancing Indebtedness shall be
     contractually subordinated in right of payment to the Notes to at least the
     same extent as the Indebtedness being refinanced,
 
          (ii) if the Indebtedness being refinanced is Non-Recourse Debt, such
     Refinancing Indebtedness shall be Non-Recourse Debt,
 
                                       31
<PAGE>   114
 
          (iii) the Refinancing Indebtedness is scheduled to mature either (a)
     no earlier than the Indebtedness being refinanced or (b) after the Stated
     Maturity of the Notes,
 
          (iv) the Refinancing Indebtedness has an Average Life at the time such
     Refinancing Indebtedness is Incurred that is equal to or greater than the
     Average Life of the Indebtedness being refinanced and
 
          (v) such Refinancing Indebtedness is in an aggregate principal amount
     (or if issued with original issue discount, an aggregate issue price) that
     is equal to or less than the aggregate principal amount (or if issued with
     original issue discount, the aggregate accreted value) then outstanding
     (plus fees and expenses, including any premium, swap breakage and
     defeasance costs) under the Indebtedness being refinanced; and provided,
     further, that Refinancing Indebtedness shall not include (x) Indebtedness
     of a Subsidiary of the Company that refinances Indebtedness of the Company
     or (y) Indebtedness of the Company or a Restricted Subsidiary that
     refinances Indebtedness of an Unrestricted Subsidiary.
 
     "Related Assets" means electric power plants that, on the Issue Date,
produce electricity solely by utilizing steam from steam fields owned and
operated by a Restricted Subsidiary that is a Wholly Owned Subsidiary on the
Issue Date.
 
     "Related Asset Indebtedness" means Non-Recourse Debt of a Restricted
Subsidiary that is a Wholly Owned Subsidiary on the Issue Date, the proceeds of
which are used by such Restricted Subsidiary to finance the acquisition of
Related Assets by such Restricted Subsidiary; provided, however, that:
 
          (i) such Related Asset Indebtedness is Incurred contemporaneously with
     a Refinancing of all of the Non-Recourse Debt of such Restricted Subsidiary
     then outstanding and
 
          (ii) the principal amount of such Related Asset Indebtedness shall not
     exceed the purchase price of the Related Assets plus reasonable
     out-of-pocket transaction costs and expenses of the Company and its
     Restricted Subsidiaries required to acquire, or finance the acquisition of,
     such Related Assets.
 
     "Restricted Subsidiary" means any Subsidiary of the Company that is not
designated an Unrestricted Subsidiary by the Board of Directors.
 
     "S&P" means Standard and Poor's Corporation and its successors.
 
     "Sale/Leaseback Transaction" means an arrangement relating to property now
owned or hereafter acquired whereby the Company or a Subsidiary transfers such
property to a Person and leases it back from such Person, other than leases for
a term of not more than 36 months or between the Company and a Wholly Owned
Subsidiary or between Wholly Owned Subsidiaries.
 
     "Senior Indebtedness" means
 
          (i) all obligations consisting of the principal of and premium, if
     any, and accrued and unpaid interest (including interest accruing on or
     after the filing of any petition in bankruptcy or for reorganization
     relating to the Company whether or not post-filing interest is allowed in
     such proceeding), whether existing on the Issue Date or thereafter
     Incurred, in respect of (A) Indebtedness of the Company for money
 
                                       32
<PAGE>   115
 
     borrowed and (B) Indebtedness evidenced by notes, debentures, bonds or
     other similar instruments for the payment of which the Company is
     responsible or liable;
 
          (ii) all Capitalized Lease Obligations of the Company;
 
          (iii) all obligations of the Company (A) for the reimbursement of any
     obligor on any letter of credit, banker's acceptance or similar credit
     transaction, (B) under Interest Rate Agreements and Currency Agreements
     entered into in respect of any obligations described in clauses (i) and
     (ii) or (C) issued or assumed as the deferred purchase price of property,
     and all conditional sale obligations of the Company and all obligations of
     the Company under any title retention agreement;
 
          (iv) all guarantees of the Company with respect to obligations of
     other persons of the type referred to in clauses (ii) and (iii) and with
     respect to the payment of dividends of other Persons; and
 
          (v) all obligations of the Company consisting of modifications,
     renewals, extensions, replacements and refundings of any obligations
     described in clauses (i), (ii), (iii) or (iv); unless, in the instrument
     creating or evidencing the same or pursuant to which the same is
     outstanding, it is provided that such obligations are subordinated in right
     of payment to the Notes, or any other Indebtedness or obligation of the
     Company; provided, however, that Senior Indebtedness shall not be deemed to
     include (1) any obligation of the Company to any Subsidiary, (2) any
     liability for Federal, state, local or other taxes or (3) any accounts
     payable or other liability to trade creditors arising in the ordinary
     course of business (including guarantees thereof or instruments evidencing
     such liabilities).
 
     "Significant Subsidiary" means any Subsidiary (other than an Unrestricted
Subsidiary) that would be a "Significant Subsidiary" of the Company within the
meaning of Rule 1-02 under Regulations S-X promulgated by the SEC.
 
     "Stated Maturity" means, with respect to any security, the date specified
in such security as the fixed date on which the principal of such security is
due and payable, including pursuant to any mandatory redemption provision (but
excluding any provision providing for the repurchase of such security at the
option of the holder thereof upon the happening of any contingency).
 
     "Subordinated Indebtedness" means any Indebtedness of the Company (whether
outstanding on the Issue Date or thereafter Incurred) which is contractually
subordinated or junior in right of payment to the Notes or any other
Indebtedness of the Company.
 
     "Subsidiary" means, as applied to any Person, any corporation, limited or
general partnership, trust, association or other business entity of which an
aggregate of at least 50% of the outstanding Voting Shares or an equivalent
controlling interest therein, of such Person is, at the time, directly or
indirectly, owned by such Person and/or one or more Subsidiaries of such Person.
 
     "Unrelated Business" means any business other than the Line of Business.
 
     "Unrestricted Subsidiary" means
 
          (i) any Subsidiary that at the time of determination shall be
     designated an Unrestricted Subsidiary by the Board of Directors in the
     manner provided below and
 
          (ii) any subsidiary of an Unrestricted Subsidiary.
 
                                       33
<PAGE>   116
 
     The Board of Directors may designate any Subsidiary (including any newly
acquired or newly formed Subsidiary) to be an Unrestricted Subsidiary unless
such Subsidiary owns any Capital Stock of, or owns or holds any Lien on any
property of, the Company or any other Subsidiary that is not a Subsidiary of the
Subsidiary to be so designated; provided, that either:
 
             (A) the Subsidiary to be so designated has total assets of $1,000
        or less or
 
             (B) if such Subsidiary has assets greater than $1,000, that such
        designation would be permitted pursuant to the provisions under
        "Covenants -- Limitation on Restricted Payments." The Board of Directors
        may designate any Unrestricted Subsidiary to be a Restricted Subsidiary
        of the Company; provided, however, that immediately after giving effect
        to such designation
 
                  (x) the Company could Incur $1.00 of additional Indebtedness
             pursuant to the first paragraph of "Covenants -- Limitation on
             Incurrence of Indebtedness" and
 
                  (y) no Default or Event of Default shall have occurred and be
             continuing.
 
     Any such designation by the Board of Directors shall be evidenced to the
Trustee by promptly filing with the Trustee a copy of the board resolution
giving effect to such designation and an Officers' Certificate certifying that
such designation complied with the foregoing provisions; provided, however, that
the failure to so file such resolution and/or Officers' Certificate with the
Trustee shall not impair or affect the validity of such designation.
 
     "U.S. Government Obligations" means securities that are:
 
          (i) direct obligations of the United States of America for the payment
     of which its full faith and credit is pledged or
 
          (ii) obligations of a Person controlled or supervised by and acting as
     an agency or instrumentality of the United States of America the payment of
     which is unconditionally guaranteed as a full faith and credit obligation
     by the United States of America, which, in either case under clauses (i) or
     (ii) are not callable or redeemable before the maturity thereof.
 
     "Voting Shares," with respect to any corporation, means the Capital Stock
having the general voting power under ordinary circumstances to elect at least a
majority of the board of directors (irrespective of whether or not at the time
stock of any other class or classes shall have or might have voting power by
reason of the happening of any contingency).
 
     "Wholly Owned Subsidiary" means a Subsidiary (other than an Unrestricted
Subsidiary) all the Capital Stock of which (other than directors' qualifying
shares) is owned by the Company or another Wholly Owned Subsidiary.
 
     "Working Capital Credit Agreement" means the Line of Credit Note, dated as
of June 4, 1993, between the Company and The Bank of California, N.A. as
amended, refinanced, renewed or extended from time to time.
 
                                       34
<PAGE>   117
 
COVENANTS
 
     The Indenture contains covenants including, among others, the following:
 
     Limitation on Restricted Payments. Under the terms of the Indenture, so
long as any of the Notes are outstanding, the Company shall not, and shall not
permit any Restricted Subsidiary to, directly or indirectly,
 
          (i) declare or pay any dividend on or make any distribution or similar
     payment of any sort in respect of its Capital Stock (including any payment
     in connection with any merger or consolidation involving the Company) to
     the direct or indirect holders of its Capital Stock (other than dividends
     or distributions payable solely in its Non-Convertible Capital Stock or
     rights to acquire its Non-Convertible Capital Stock and dividends or
     distributions payable solely to the Company or a Restricted Subsidiary and
     other than pro rata dividends paid by a Subsidiary with respect to a series
     or class of its Capital Stock the majority of which is held by the Company
     or a Wholly Owned Subsidiary that is not a Foreign Subsidiary),
 
          (ii) purchase, redeem, defease or otherwise acquire or retire for
     value any Capital Stock of the Company or of any direct or indirect parent
     of the Company, or, with respect to the Company, exercise any option to
     exchange any Capital Stock that by its terms is exchangeable solely at the
     option of the Company (other than into Capital Stock of the Company which
     is neither Exchangeable Stock nor Redeemable Stock),
 
          (iii) purchase, repurchase, redeem, defease or otherwise acquire or
     retire for value, prior to scheduled maturity or scheduled repayment
     thereof or scheduled sinking fund payment thereon, any Subordinated
     Indebtedness (other than the purchase, repurchase or other acquisition of
     Subordinated Indebtedness purchased in anticipation of satisfying a sinking
     fund obligation, principal installment or final maturity, in each case due
     within one year of the date of acquisition) or
 
          (iv) make any Investment, other than a Controlled Non-Subsidiary
     Investment, or a payment described in clause (vi) of the second sentence
     under "-- Covenants -- Transactions with Affiliates," in any Unrestricted
     Subsidiary or any Affiliate of the Company other than a Restricted
     Subsidiary or a Person which will become a Restricted Subsidiary as a
     result of any such Investment (each such payment described in clauses
     (i) - (iv) of this paragraph, a "Restricted Payment"), unless at the time
     of and after giving effect to the proposed Restricted Payment:
 
             (1) no Default or Event of Default shall have occurred and be
        continuing (or would result therefrom);
 
             (2) the Company would be permitted to Incur an additional $1 of
        Indebtedness pursuant to the provisions described in the first paragraph
        under "-- Limitation on Incurrence of Indebtedness," and
 
             (3) the aggregate amount of all such Restricted Payments subsequent
        to the Issue Date shall not exceed the sum of
 
                  (A) 50% of aggregate Consolidated Net Income accrued during
             the period (treated as one accounting period) from January 1, 1994
             to the end of the most recent fiscal quarter for which financial
             statements are available (or if such Consolidated Net Income is a
             deficit, minus 100% of such
 
                                       35
<PAGE>   118
 
             deficit), and minus 100% of the amount of any write-downs,
             write-offs, other negative reevaluations and other negative
             extraordinary charges not otherwise reflected in Consolidated Net
             Income during such period;
 
                  (B) if the Notes are Investment Grade immediately following
             the Restricted Payment in connection with which this calculation is
             made, an additional 25% of Consolidated Net Income for any period
             of one or more consecutive completed fiscal quarters ending with
             the last fiscal quarter completed prior to the date of such
             Restricted Payment during which the Notes were Investment Grade for
             the entire period;
 
                  (C) the aggregate Net Cash Proceeds received by the Company
             after January 1, 1994 from the sale of Capital Stock (other than
             Redeemable Stock or Exchangeable Stock) of the Company to any
             person other than the Company, any of its Subsidiaries or an
             employee stock ownership plan;
 
                  (D) the amount by which the principal amount of, and any
             accrued interest on, Indebtedness of the Company or its Restricted
             Subsidiaries is reduced on the Company's Consolidated balance sheet
             upon the conversion or exchange (other than by a Subsidiary)
             subsequent to the Issue Date of any Indebtedness of the Company or
             any Restricted Subsidiary converted or exchanged for Capital Stock
             (other than Redeemable Stock or Exchangeable Stock) of the Company
             (less the amount of any cash, or the value of any other property,
             distributed by the Company or any Restricted Subsidiary upon such
             conversion or exchange);
 
                  (E) an amount equal to the net reduction in Investments in
             Unrestricted Subsidiaries resulting from payments of interest on
             Indebtedness, dividends, repayments of loans or advances, or other
             transfers of assets, in each case to the Company or any Restricted
             Subsidiary from Unrestricted Subsidiaries, or from redesignations
             of Unrestricted Subsidiaries as Restricted Subsidiaries (valued in
             each case as provided in the definition of "Investments"), not to
             exceed in the case of any Unrestricted Subsidiary the amount of
             Investments previously made by the Company or any Restricted
             Subsidiary in such Unrestricted Subsidiary; and
 
                  (F) $25,000,000.
 
     The failure to satisfy the conditions set forth in clauses (2) and (3)
above shall not prohibit any of the following as long as the condition set forth
in clause (1) of such paragraph is satisfied (except as set forth below):
 
          (i) dividends paid within 60 days after the date of declaration
     thereof if at such date of declaration such dividend would have complied
     with the provisions described above under "-- Limitation on Restricted
     Payments"; provided, however, notwithstanding clause (1) above, the
     occurrence or existence of a Default at the time of payment shall not
     prohibit the payment of such dividends;
 
          (ii) any purchase, redemption, defeasance, or other acquisition or
     retirement for value of Capital Stock or Subordinated Indebtedness of the
     Company made by exchange for, or out of the proceeds of the substantially
     concurrent sale of, Capital Stock of the Company (other than Redeemable
     Stock or Exchangeable Stock and other than stock issued or sold to a
     Subsidiary or to an employee stock ownership
 
                                       36
<PAGE>   119
 
     plan), provided, however, that notwithstanding clause (1) above under
     " -- Limitation on Restricted Payments," the occurrence or existence of a
     Default or Event of Default shall not prohibit, for purposes of this
     Section, the making of such purchase, redemption, defeasance or other
     acquisition or retirement, and provided, further, such purchase,
     redemption, defeasance or other acquisition or retirement shall not be
     included in the calculation of Restricted Payments made for purposes of
     clause (3) above under "-- Limitation on Restricted Payments," and
     provided, further, that the Net Cash Proceeds from such sale shall be
     excluded from sub-clause (C) of clause (3) above under "-- Limitation on
     Restricted Payments";
 
          (iii) any purchase, redemption, defeasance or other acquisition or
     retirement for value of Subordinated Indebtedness of the Company made by
     exchange for, or out of the proceeds of the substantially concurrent
     Incurrence of for cash (other than to a Subsidiary), new Indebtedness of
     the Company, provided, however, that,
 
             (A) such new Indebtedness shall be contractually subordinated in
        right of payment to the Securities at least to the same extent as the
        Indebtedness being so redeemed, repurchased, defeased, acquired or
        retired,
 
             (B) if the Indebtedness being purchased, redeemed, defeased or
        acquired or retired for value is Non-Recourse Debt, such new
        Indebtedness shall be Non-Recourse Debt,
 
             (C) such new Indebtedness has a Stated Maturity either (1) no
        earlier than the Stated Maturity of the Indebtedness redeemed,
        repurchased, defeased, acquired or retired or (2) after the Stated
        Maturity of the Notes and
 
             (D) such Indebtedness has an Average Life equal to or greater than
        the Average Life of the Indebtedness redeemed, repurchased, defeased,
        acquired or retired, and provided, further, that such purchase,
        redemption, defeasance or other acquisition or retirement shall not be
        included in the calculation of Restricted Payments made for purposes of
        clause (3) above under "-- Limitation on Restricted Payments";
 
          (iv) any purchase, redemption, defeasance or other acquisition or
     retirement for value of Subordinated Indebtedness upon a Change of Control
     or an Asset Sale to the extent required by the indenture or other agreement
     pursuant to which such Subordinated Indebtedness was issued, but only if
     the Company (A) in the case of a Change of Control, has made an offer to
     repurchase the Notes as described under "-- Covenants -- Change of Control"
     or (B) in the case of an Asset Sale, has applied the Net Available Cash
     from such Asset Sale in accordance with the provisions described under
     "-- Covenants -- Sales of Assets."
 
     Limitation on Incurrence of Indebtedness. Under the terms of the Indenture,
the Company shall not, and shall not permit any Restricted Subsidiary to,
directly or indirectly, Incur any Indebtedness, except that the Company may
Incur Indebtedness if, after giving effect thereto, the Consolidated Coverage
Ratio would be greater than 2:1.
 
     The foregoing provision will not limit the ability of the Company or any
Restricted Subsidiary to Incur the following Indebtedness:
 
          (i) Refinancing Indebtedness (except with respect to Indebtedness
     referred to in clause (ii), (iii) or (iv) below);
 
                                       37
<PAGE>   120
 
          (ii) in addition to any Indebtedness otherwise permitted to be
     Incurred hereunder, Indebtedness of the Company at any one time outstanding
     in an aggregate principal amount not to exceed $50,000,000 and provided
     that the proceeds of such Indebtedness shall not be used for the purpose of
     making any Restricted Payments described in clause (i) or (ii) under
     "-- Limitation on Restricted Payments";
 
          (iii) Indebtedness of the Company which is owed to and held by a
     Wholly Owned Subsidiary and Indebtedness of a Wholly Owned Subsidiary which
     is owed to and held by the Company or a Wholly Owned Subsidiary; provided,
     however, that any subsequent issuance or transfer of any Capital Stock
     which results in any such Wholly Owned Subsidiary ceasing to be a Wholly
     Owned Subsidiary or any transfer of such Indebtedness (other than to the
     Company or a Wholly Owned Subsidiary) shall be deemed, in each case, to
     constitute the Incurrence of such Indebtedness by the Company or by a
     Wholly Owned Subsidiary, as the case may be;
 
          (iv) Indebtedness of the Company under the Bank Credit Agreement
     which, when taken together with the aggregate amount of Indebtedness
     Incurred pursuant to clause (viii) of this paragraph, is not in excess of
     $50,000,000, and Indebtedness of the Company under the Working Capital
     Credit Agreement not in excess of $50,000,000;
 
          (v) Acquired Indebtedness; provided, however, that the Company would
     have been able to Incur such Indebtedness at the time of the Incurrence
     thereof pursuant to the immediately preceding paragraph;
 
          (vi) Indebtedness of the Company or a Restricted Subsidiary
     outstanding on the Issue Date (other than Indebtedness referred to in
     clause (iv) above and Indebtedness being repaid or retired with the
     proceeds of the Offering);
 
          (vii) Non-Recourse Debt of a Restricted Subsidiary (other than a
     Restricted Subsidiary existing on the Issue Date), the proceeds of which
     are used to acquire, develop, improve or construct a new Facility of such
     Restricted Subsidiary;
 
          (viii) guarantees by the Company of Indebtedness of Restricted
     Subsidiaries which, but for such guarantees, would be permitted to be
     Incurred pursuant to clause (vii) of this paragraph, provided that the
     aggregate principal amount of Indebtedness Incurred pursuant to this clause
     (viii), when taken together with outstanding Indebtedness Incurred under
     the Bank Credit Agreement pursuant to clause (iv) of this paragraph, is not
     in excess of $50,000,000; and
 
          (ix) Related Asset Indebtedness, provided that at the time of the
     Incurrence thereof, giving pro forma effect to the Incurrence thereof,
     Moody's and S&P shall have affirmed their respective ratings of the Notes
     in effect prior to the Incurrence of such Related Asset Indebtedness.
 
     Notwithstanding the provisions of this covenant described in the first two
paragraphs above, the Indenture provides that the Company shall not Incur any
Indebtedness if the proceeds thereof are used, directly or indirectly, to repay,
prepay, redeem, defease, retire, refund or refinance any Subordinated
Indebtedness unless such repayment, prepayment, redemption, defeasance,
retirement, refunding or refinancing is not prohibited under "-- Limitation on
Restricted Payments" or unless such Indebtedness shall be contractually
subordinated to the Notes at least to the same extent as such Subordinated
Indebtedness.
 
                                       38
<PAGE>   121
 
     Limitation on Payment Restrictions Affecting Subsidiaries. Under the terms
of the Indenture, the Company shall not, and shall not permit any Subsidiary to,
create or otherwise cause or permit to exist or become effective any consensual
encumbrance or restriction on the ability of any Restricted Subsidiary to:
 
          (i) pay dividends to or make any other distributions on its Capital
     Stock, or pay any Indebtedness or other obligations owed to the Company or
     any other Restricted Subsidiary,
 
          (ii) make any Investments in the Company or any other Restricted
     Subsidiary or
 
          (iii) transfer any of its property or assets to the Company or any
     other Restricted Subsidiary; provided, however, that the foregoing shall
     not apply to
 
             (a) any encumbrance or restriction existing pursuant to the
        Indenture or any other agreement or instrument as in effect or entered
        into on the Issue Date;
 
             (b) any encumbrance or restriction with respect to a Subsidiary
        pursuant to an agreement relating to any Acquired Indebtedness;
        provided, however, that such encumbrance or restriction was not Incurred
        in connection with or in contemplation of such Subsidiary becoming a
        Subsidiary;
 
             (c) any encumbrance or restriction pursuant to an agreement
        effecting a refinancing of Indebtedness referred to in clause (a) or (b)
        above or contained in any amendment or modification with respect to such
        Indebtedness; provided, however, that the encumbrances and restrictions
        contained in any such agreement, amendment or modification are no less
        favorable in any material respect with respect to the matters referred
        to in clauses (i), (ii) and (iii) above than the encumbrances and
        restrictions with respect to the Indebtedness being refinanced, amended
        or modified;
 
             (d) in the case of clause (iii) above, customary non-assignment
        provisions of (A) any leases governing a leasehold interest, (B) any
        supply, license or other agreement entered into in the ordinary course
        of business of the Company or any Subsidiary or (C) any security
        agreement relating to a Lien permitted by clause (l) of the covenant
        described under "-- Limitation on Liens" below that, in the reasonable
        determination of the President or Chief Financial Officer of the Company
        (x) is required in order to obtain such financing and (y) is customary
        for such financings;
 
             (e) any restrictions with respect to a Subsidiary imposed pursuant
        to an agreement entered into for the sale or disposition of all or
        substantially all of the Capital Stock or assets of such Subsidiary
        pending the closing of such sale or disposition;
 
             (f) any encumbrance imposed pursuant to the terms of Indebtedness
        incurred pursuant to clause (vii) of the proviso to the covenant
        described under "-- Limitation on Incurrence of Indebtedness" above,
        provided that such encumbrance in the written opinion of the President
        or Chief Financial Officer of the Company, (x) is required in order to
        obtain such financing, (y) is customary for such financings and (z)
        applies only to the assets of or revenues of the applicable Facility; or
 
             (g) any encumbrance or restriction existing by reason of applicable
        law.
 
                                       39
<PAGE>   122
 
     Limitation on Sale/Leaseback Transactions. Under the terms of the
Indenture, the Company shall not, and shall not permit any Restricted Subsidiary
to, enter into any Sale/ Leaseback Transaction unless
 
          (i) the Company or such Subsidiary would be entitled to create a Lien
     on such property securing Indebtedness in an amount equal to the
     Attributable Debt with respect to such transaction without equally and
     ratably securing the Securities pursuant to the covenant entitled
     "Limitation on Liens" or
 
          (ii) the net proceeds of such sale are at least equal to the fair
     value (as determined by the Board of Directors) of such property and the
     Company or such Subsidiary shall apply or cause to be applied an amount in
     cash equal to the net proceeds of such sale to the retirement, within 30
     days of the effective date of any such arrangement, of Senior Indebtedness
     or Indebtedness of a Restricted Subsidiary; provided, however, that in
     addition to the transactions permitted pursuant to the foregoing clauses
     (i) and (ii), the Company or any Restricted Subsidiary may enter into a
     Sale/Leaseback Transaction as long as the sum of
 
             (x) the Attributable Debt with respect to such Sale/ Leaseback
        Transaction and all other Sale/Leaseback Transactions entered into
        pursuant to this proviso, plus
 
             (y) the amount of outstanding Indebtedness secured by Liens
        Incurred pursuant to the final proviso to the covenant described under
        "-- Limitation on Liens" below, does not exceed 10% of Consolidated Net
        Tangible Assets as determined based on the consolidated balance sheet of
        the Company as of the end of the most recent fiscal quarter for which
        financial statements are available; and provided, further, that a
        Restricted Subsidiary that is not a Restricted Subsidiary on the Issue
        Date may enter into a Sale/Leaseback Transaction with respect to
        property owned by such Restricted Subsidiary, the proceeds of which are
        used to acquire, develop, construct, or repay (within 365 days of the
        commencement of commercial operation of such Facility) Indebtedness
        Incurred to acquire, develop or construct, a new Facility of such
        Restricted Subsidiary, as long as neither the Company nor any other
        Restricted Subsidiary shall have any obligation or liability in
        connection therewith.
 
     Limitation on Liens. Under the terms of the Indenture, the Company shall
not, and shall not permit any Restricted Subsidiary to, directly or indirectly,
incur or permit to exist any Lien of any nature whatsoever on any of its
properties (including, without limitation, Capital Stock), whether owned at the
date of such Indenture or thereafter acquired, other than
 
          (a) pledges or deposits made by such Person under workers'
     compensation, unemployment insurance laws or similar legislation, or good
     faith deposits in connection with bids, tenders, contracts (other than for
     payment of Indebtedness) or leases to which such Person is a party, or
     deposits to secure statutory or regulatory obligations of such Person or
     deposits of cash of United States Government bonds to secure surety, appeal
     or performance bonds to which such Person is a party, or deposits as
     security for contested taxes or import duties or for the payment of rent,
     in each case Incurred in the ordinary course of business;
 
          (b) Liens imposed by law such as carriers', warehousemen's and
     mechanics' Liens, in each case, arising in the ordinary course of business
     and with respect to
 
                                       40
<PAGE>   123
 
     amounts not yet due or being contested in good faith by appropriate legal
     proceedings promptly instituted and diligently conducted and for which a
     reserve or other appropriate provision, if any, as shall be required in
     conformity with GAAP shall have been made; or other Liens arising out of
     judgments or awards against such Person with respect to which such Person
     shall then be diligently prosecuting appeal or other proceedings for
     review;
 
          (c) Liens for property taxes not yet subject to penalties for
     non-payment or which are being contested in good faith and by appropriate
     legal proceedings promptly instituted and diligently conducted and for
     which a reserve or other appropriate provision, if any, as shall be
     required in conformity with GAAP shall have been made;
 
          (d) Liens in favor of issuers or surety bonds or letters of credit
     issued pursuant to the request of and for the account of such Person in the
     ordinary course of its business; provided, however, that such letters of
     credit may not constitute Indebtedness;
 
          (e) minor survey exceptions, minor encumbrances, easements or
     reservations of, or rights of others for, rights of way, sewers, electric
     lines, telegraph and telephone lines and other similar purposes, or zoning
     or other restrictions as to the use of real properties or liens incidental
     to the conduct of the business of such Person or to the ownership of its
     properties which were not Incurred in connection with Indebtedness or other
     extensions of credit and which do not in the aggregate materially adversely
     affect the value of said properties or materially impair their use in the
     operation of the business of such Person;
 
          (f) Liens securing Indebtedness Incurred to finance the construction
     or purchase of, or repairs, improvements or additions to, property, which
     shall include, without limitation, Liens on the stock of the Restricted
     Subsidiary that has purchased or owns such property; provided, however,
     that the Lien may not extend to any other property owned by the Company or
     any Restricted Subsidiary at the time the Lien is incurred, and the
     Indebtedness secured by the Lien may not be issued more than 270 days after
     the later of the acquisition, completion of construction, repair,
     improvement, addition or commencement of full operation of the property
     subject to the Lien;
 
          (g) Liens existing on the Issue Date (other than Liens relating to
     Indebtedness or other obligations being repaid or liens that are otherwise
     extinguished with the proceeds of the Offering);
 
          (h) Liens on property or shares of stock of a Person at the time such
     Person becomes a Subsidiary; provided, however, that any such lien may not
     extend to any other property owned by the Company or any Restricted
     Subsidiary;
 
          (i) Liens on property at the time the Company or a Subsidiary acquires
     the property, including any acquisition by means of a merger or
     consolidation with or into the Company or a Subsidiary; provided, however,
     that such Liens are not incurred in connection with, or in contemplation
     of, such merger or consolidation; and provided, further, that the Lien may
     not extend to any other property owned by the Company or any Restricted
     Subsidiary;
 
          (j) Liens securing Indebtedness or other obligations of a Subsidiary
     owing to the Company or a Wholly Owned Subsidiary;
 
                                       41
<PAGE>   124
 
          (k) Liens incurred by a Person other than the Company or any
     Subsidiary on assets that are the subject of a Capitalized Lease Obligation
     to which the Company or a Subsidiary is a party; provided, however, that
     any such Lien may not secure Indebtedness of the Company or any Subsidiary
     (except by virtue of clause (ix) of the definition of "Indebtedness") and
     may not extend to any other property owned by the Company or any Restricted
     Subsidiary;
 
          (l) Liens Incurred by a Restricted Subsidiary on its assets to secure
     Non-Recourse Debt Incurred pursuant to clause (vii) of the second paragraph
     under "-- Limitation on Incurrence of Indebtedness" above, provided that
     such Lien (A) is incurred at the time of the initial Incurrence of such
     Indebtedness and (B) does not extend to any assets or property of the
     Company or any other Restricted Subsidiary;
 
          (m) Liens not in respect of Indebtedness arising from Uniform
     Commercial Code financing statements for informational purposes with
     respect to leases Incurred in the ordinary course of business and not
     otherwise prohibited by this Indenture;
 
          (n) Liens not in respect of Indebtedness consisting of the interest of
     the lessor under any lease Incurred in the ordinary course of business and
     not otherwise prohibited by this Indenture;
 
          (o) Liens which constitute banker's liens, rights of set-off or
     similar rights and remedies as to deposit accounts or other funds
     maintained with any bank or other financial institution, whether arising by
     operation of law or pursuant to contract;
 
          (p) Liens to secure any refinancing, refunding, extension, renewal or
     replacement (or successive refinancings, refundings, extensions, renewals
     or replacements) as a whole, or in part, of any Indebtedness secured by any
     Lien referred to in the foregoing clauses (f), (g), (h) and (i), provided,
     however, that (x) such new Lien shall be limited to all or part of the same
     property that secured the original Lien (plus improvements on such
     property) and (y) the Indebtedness secured by such Lien at such time is not
     increased (other than by an amount necessary to pay fees and expenses,
     including premiums, related to the refinancing, refunding, extension,
     renewal or replacement of such Indebtedness); and
 
          (q) Liens by which the Notes are secured equally and ratably with
     other Indebtedness of the Company pursuant to the provisions described
     under "-- Covenants -- Limitations on Liens," without effectively providing
     that the Notes shall be secured equally and ratably with (or prior to) the
     obligations so secured for so long as such obligations are so secured; and
 
          (r) Liens on assets relating to the Magic Valley Generating Station;
 
     provided, however, that the Company may incur other Liens to secure
     Indebtedness as long as the sum of (x) the amount of outstanding
     Indebtedness secured by Liens incurred pursuant to this proviso plus (y)
     the Attributable Debt with respect to all outstanding leases in connection
     with Sale/Leaseback Transactions entered into pursuant to the proviso under
     "-- Limitation on Sale/Leaseback Transactions," does not exceed 10% of
     Consolidated Net Tangible Assets as determined with respect to the Company
     as of the end of the most recent fiscal quarter for which financial
     statements are available.
 
     Change of Control. Under the terms of the Indenture, in the event of a
Change of Control Triggering Event, the Company shall make an offer to purchase
(the "Change of
 
                                       42
<PAGE>   125
 
Control Offer") the Notes then outstanding at a purchase price equal to 101% of
the principal amount (excluding any premium) thereof plus accrued and unpaid
interest to the Change of Control Purchase Date (as defined below) on the terms
set forth in this provision. The date on which the Company shall purchase the
Notes pursuant to this provision (the "Change of Control Purchase Date") shall
be no earlier than 30 days, nor later than 60 days, after the notice referred to
below is mailed, unless a longer period shall be required by law. The Company
shall notify the Trustee in writing promptly after the occurrence of any Change
of Control Triggering Event of the Company's obligation to offer to purchase all
of the Notes.
 
     Notice of a Change of Control Offer shall be mailed by the Company to the
Holders of the Notes at their last registered address (with a copy to the
Trustee and the Paying Agent) within thirty (30) days after a Change in Control
Triggering Event has occurred. The Change of Control Offer shall remain open
from the time of mailing until a date not more than five (5) Business Days
before the Change of Control Purchase Date. The notice shall contain all
instructions and materials necessary to enable such Holders to tender (in whole
or in part) the Notes pursuant to the Change of Control Offer. The notice, which
shall govern the terms of the Change of Control Offer, shall state:
 
          (a) that the Change of Control Offer is being made pursuant to the
     Indenture;
 
          (b) the purchase price and the Change of Control Purchase Date;
 
          (c) that any Note not surrendered or accepted for payment will
     continue to accrue interest;
 
          (d) that any Note accepted for payment pursuant to the Change of
     Control Offer shall cease to accrue interest after the Change of Control
     Purchase Date;
 
          (e) that any Holder electing to have a Note purchased (in whole or in
     part) pursuant to a Change of Control Offer will be required to surrender
     the Note, with the form entitled "Option of Holder to Elect Purchase" on
     the reverse of the Note completed, to the Paying Agent at the address
     specified in the notice (or otherwise make effective delivery of the Note
     pursuant to book-entry procedures and the related rules of the applicable
     depositories) at least five (5) Business Days before the Change of Control
     Purchase Date; and
 
          (f) that any Holder will be entitled to withdraw his or her election
     if the Paying Agent receives, not later than three (3) Business Days prior
     to the Change of Control Purchase Date, a telegram, telex, facsimile
     transmission or letter setting forth the name of the Holder, the principal
     amount of the Note the Holder delivered for purchase and a statement that
     such Holder is withdrawing his or her election to have the Note purchased.
 
     On the Change of Control Purchase Date, the Company shall:
 
          (i) accept for payment the Notes, or portions thereof, surrendered and
     properly tendered and not withdrawn, pursuant to the Change of Control
     Offer,
 
          (ii) deposit with the Paying Agent, no later than 11:00 a.m. eastern
     standard time, money, in immediately available funds, sufficient to pay the
     purchase price of all the Notes or portions thereof so accepted and
 
                                       43
<PAGE>   126
 
          (iii) deliver to the Trustee, no later than 11:00 a.m. eastern
     standard time, the Notes so accepted together with an Officers' Certificate
     stating that such Notes have been accepted for payment by the Company. The
     Paying Agent shall promptly mail or deliver to Holders of Notes so accepted
     payment in an amount equal to the purchase price. Holders whose Notes are
     purchased only in part will be issued new Notes equal in principal amount
     to the unpurchased portion of the Notes surrendered.
 
     Transactions with Affiliates. Under the terms of the Indenture, the Company
shall not, and shall not permit any Restricted Subsidiary to, directly or
indirectly, enter into, permit to exist, renew or extend any transaction or
series of transactions (including, without limitation, the sale, purchase,
exchange or lease of any assets or property or the rendering of any services)
with any Affiliate of the Company unless
 
          (i) the terms of such transaction or series of transactions are (A) no
     less favorable to the Company or such Restricted Subsidiary, as the case
     may be, than would be obtainable in a comparable transaction or series of
     related transactions in arm's-length dealings with an unrelated third-party
     and (B) set forth in writing, if such transaction or series of transactions
     involve aggregate payments or consideration in excess of $1,000,000, and
 
          (ii) with respect to a transaction or series of transactions involving
     the sale, purchase, lease or exchange of property or assets having a value
     in excess of $5,000,000, such transaction or series of transactions has
     been approved by a majority of the disinterested members of the Board of
     Directors or, if there are no disinterested members of the Board of
     Directors, the Board of Directors of the Company shall have received a
     written opinion of a nationally recognized investment banking firm stating
     that such transaction or series of transactions is fair to the Company or
     such Restricted Subsidiary from a financial point of view.
 
     The foregoing provisions do not prohibit
 
          (i) the payment of reasonable fees to directors of the Company and its
     subsidiaries who are not employees of the Company or its subsidiaries;
 
          (ii) any transaction between the Company and a Wholly Owned Subsidiary
     or between Wholly Owned Subsidiaries otherwise permitted by the terms of
     the Indenture;
 
          (iii) the payment of any Restricted Payment which is expressly
     permitted to be paid pursuant to the second paragraph under "-- Covenants
     -- Limitation on Restricted Payments;"
 
          (iv) any issuance of securities or other reasonable payments, awards
     or grants, in cash or otherwise, pursuant to, or the funding of, employment
     arrangements approved by the Board of Directors;
 
          (v) the grant of stock options or similar rights to employees and
     directors of the Company pursuant to plans approved by the Board of
     Directors;
 
          (vi) loans or advances to employees in the ordinary course of
     business;
 
          (vii) any repurchase, redemption or other retirement of Capital Stock
     of the Company held by employees of the Company or any of its Subsidiaries
     upon death,
 
                                       44
<PAGE>   127
 
     disability or termination of employment at a price not in excess of the
     fair market value thereof approved by the Board of Directors;
 
          (viii) any transaction between or among the Company and any Subsidiary
     in the ordinary course of business and consistent with past practices of
     the Company and its Subsidiaries;
 
          (ix) payments of principal, interest and commitment fees under the
     Bank Credit Agreement; and
 
          (x) any agreement to do any of the foregoing. Any transaction which
     has been determined, in the written opinion of an independent nationally
     recognized investment banking firm, to be fair, from a financial point of
     view, to the Company or the applicable Restricted Subsidiary shall be
     deemed to be in compliance with this provision.
 
     Sales of Assets. Under the terms of the Indenture, neither the Company nor
any Restricted Subsidiary shall consummate any Asset Sale unless:
 
          (i) the Company or such Restricted Subsidiary receives consideration
     at the time of such Asset Sale at least equal to the fair market value, as
     determined in good faith by the Board of Directors, of the shares or assets
     subject to such Asset Sale,
 
          (ii) at least 60% of the consideration thereof received by the Company
     or such Restricted Subsidiary is in the form of cash or cash equivalents
     which are promptly converted into cash by the Person receiving such
     payment, and
 
          (iii) an amount equal to 100% of the Net Available Cash is applied by
     the Company (or such Subsidiary, as the case may be) as set forth herein.
 
     Under the terms of the Indenture, the Company shall not permit any
Unrestricted Subsidiary to make any Asset Sale unless such Unrestricted
Subsidiary receives consideration at the time of such Asset Sale at least equal
to the fair market value of the shares or assets so disposed of as determined in
good faith by the Board of Directors.
 
     Under the terms of the Indenture, within 365 days (such period being the
"Application Period") following the consummation of an Asset Sale, the Company
or such Restricted Subsidiary shall apply the Net Available Cash from such Asset
Sale as follows:
 
          (i) first, to the extent the Company or such Restricted Subsidiary
     elects, to reinvest in Additional Assets (including by means of an
     investment in Additional Assets by a Restricted Subsidiary with Net
     Available Cash received by the Company or another Restricted Subsidiary);
 
          (ii) second, to the extent of the balance of such Net Available Cash
     after application in accordance with clause (i), and to the extent the
     Company or such Restricted Subsidiary elects (or is required by the terms
     of any Senior Indebtedness or any Indebtedness of such Restricted
     Subsidiary), to prepay, repay or purchase Senior Indebtedness (other than
     Notes) or Indebtedness (other than any Preferred Stock) of a Restricted
     Subsidiary (in each case other than Indebtedness owed to the Company or an
     Affiliate of the Company);
 
          (iii) third, to the extent of the balance of such Net Available Cash
     after application in accordance with clauses (i) and (ii), and to the
     extent the Company or such Restricted Subsidiary elects, to purchase Notes;
     and
 
                                       45
<PAGE>   128
 
          (iv) fourth, to the extent of the balance of such Net Available Cash
     after application in accordance with clauses (i), (ii) and (iii), to make
     an offer to purchase the Notes at not less than their principal amount plus
     accrued interest (if any) pursuant to and subject to the conditions set
     forth in the Indenture; provided, however, that in connection with any
     prepayment, repayment or purchase of Indebtedness pursuant to clause (ii),
     (iii) or (iv) above, the Company or such Restricted Subsidiary shall retire
     such Indebtedness and cause the related loan commitment (if any) to be
     permanently reduced in an amount equal to the principal amount so prepaid,
     repaid or purchased.
 
     To the extent that any Net Available Cash from any Asset Sale remains after
the application of such Net Available Cash in accordance with this paragraph,
the Company or such Restricted Subsidiary may utilize such remaining Net
Available Cash in any manner not otherwise prohibited by the Indenture.
 
     To the extent that any or all of the Net Available Cash of any Foreign
Asset Sale is prohibited or delayed by applicable local law from being
repatriated to the United States, the portion of such Net Available Cash so
affected shall not be required to be applied at the time provided above, but may
be retained by the applicable Restricted Subsidiary so long, but only so long,
as the applicable local law will not permit repatriation to the United States
(the Company hereby agreeing to promptly take or cause the applicable Restricted
Subsidiary to promptly take all actions required by the applicable local law to
permit such repatriation). Once such repatriation of any of such affected Net
Available Cash is permitted under the applicable local law, such repatriation
shall be immediately effected and such repatriated Net Available Cash will be
applied in the manner set forth in this provision as if such Asset Sale had
occurred on the date of such repatriation.
 
     Notwithstanding the foregoing, to the extent that the Board of Directors
determines, in good faith, that repatriation of any or all of the Net Available
Cash of any Foreign Asset Sale would have a material adverse tax consequence to
the Company, the Net Available Cash so affected may be retained outside of the
United States by the applicable Restricted Subsidiary for so long as such
material adverse tax consequence would continue.
 
     Under the Indenture, the Company shall not be required to make an offer to
purchase the Notes if the Net Available Cash available from an Asset Sale (after
application of the proceeds as provided in clauses (i) and (ii) of the second
paragraph above) is less than $1,000,000 for any particular Asset Sale (which
lesser amounts shall not be carried forward for purposes of determining whether
an offer is required with respect to the Net Available Cash from any subsequent
Asset Sale).
 
     Notwithstanding the foregoing, this provision shall not apply to, or
prevent any sale of assets, property, or Capital Stock of Subsidiaries to the
extent that the fair market value (as determined in good faith by the Board of
Directors) of such asset, property or Capital Stock, together with the fair
market value of all other assets, property, or Capital Stock of Subsidiaries
sold, transferred or otherwise disposed of in Asset Sales during the twelve
month period preceding the date of such sale, does not exceed 5% of Consolidated
Net Tangible Assets as determined as of the end of the most recent fiscal
quarter for which financial statements are available (it being understood that
this provision shall only apply with respect to the fair market value of such
asset, property or Capital Stock in excess of 5% of consolidated Net Tangible
Assets), and no violation of this provision shall be deemed to have occurred as
a consequence thereof.
 
                                       46
<PAGE>   129
 
     In the event of the transfer of substantially all (but not all) of the
property and assets of the Company as an entirety to a Person in a transaction
permitted under the covenant described under "-- Merger and Consolidation," the
Successor Corporation shall be deemed to have sold the properties and assets of
the Company not so transferred for purposes of this covenant, and shall comply
with the provisions of this covenant with respect to such deemed sale as if it
were an Asset Sale.
 
     Limitation on the Issuance of Capital Stock and the Incurrence of
Indebtedness of Restricted Subsidiaries. Pursuant to the terms of the Indenture,
the Company shall not permit any Restricted Subsidiary, directly or indirectly,
to issue or sell, and shall not permit any Person other than the Company or a
Wholly Owned Subsidiary to own (except to the extent that any such Person may
own on the Issue Date), any shares of such Restricted Subsidiary's Capital Stock
(including options, warrants or other rights to purchase shares of Capital
Stock) except, to the extent otherwise permitted by the Indenture,
 
          (i) to the Company or another Restricted Subsidiary that is a Wholly
     Owned Subsidiary of the Company, or
 
          (ii) if, immediately after giving effect to such issuance and sale,
     such Restricted Subsidiary would no longer constitute a Restricted
     Subsidiary for purposes of the Indenture; provided, however, that a
     Restricted Subsidiary that has an interest in a Facility may sell shares of
     Non-Convertible Stock that is not Preferred Stock if, after giving effect
     to such sale, the Company or a Wholly Owned Subsidiary continues to hold at
     least a majority of each class of Capital Stock of such Restricted
     Subsidiary. The Company shall not permit any Restricted Subsidiary,
     directly or indirectly, to Incur Indebtedness other than pursuant to the
     second paragraph under "-- Limitation on Incurrence of Indebtedness."
 
     Limitation on Changes in the Nature of the Business. The Indenture provides
that the Company and its Subsidiaries shall engage only in the business of
acquiring, constructing, managing, developing, improving, owning and operating
Facilities, as well as any other activities reasonably related to the foregoing
activities (including acquiring and holding reserves), including but not limited
to investing in Facilities; provided that up to 10% of the Company's
Consolidated total assets may be used in Unrelated Businesses without
constituting a violation of this covenant. In addition, the Company will, and
will cause its Subsidiaries, to conduct their respective businesses in a manner
so as to maintain the exemption of the Company and its Subsidiaries from
treatment as a public utility holding company under PUHCA or an electric utility
or public utility under any federal, state or local law; provided, however, to
the extent that any such law is amended following the Issue Date in such a
manner that would (absent application of this proviso) make compliance with this
paragraph result in a material adverse effect on the Company's results of
operations or financial condition, then the Company shall not be required to
comply with this paragraph, but only to the extent of actions or failures to act
that would (absent application of this proviso) constitute violations of this
Covenant solely as a result of such amendment.
 
     Limitation on Subsidiary Investments. The Indenture provides that the
Company will not permit any Subsidiary with an interest in a Facility to make
any investment in or merge with any other person with an interest in a power
generation facility or, except in connection with the acquisition of Related
Assets by such Subsidiary, in an Unrelated Business.
 
                                       47
<PAGE>   130
 
     Merger and Consolidation. Under the terms of each of the Indentures, the
Company shall not, in a single transaction or through a series of related
transactions, consolidate with or merge with or into any other corporation or
sell, assign, convey, transfer or lease or otherwise dispose of all or
substantially all of its properties and assets as an entirety to any Person or
group of affiliated Persons unless:
 
          (i) either (A) the Company shall be the continuing Person, or (B) the
     Person (if other than the Company) formed by such consolidation or into
     which the Company is merged or to which the properties and assets of the
     Company as an entirety are transferred (the "Successor Corporation") shall
     be a corporation organized and existing under the laws of the United States
     or any State thereof or the District of Columbia and shall expressly
     assume, by an indenture supplemental to the Indenture, executed and
     delivered to the Trustee, in form and substance reasonably satisfactory to
     the Trustee, all the obligations of the Company under the Indenture and the
     Notes;
 
          (ii) immediately before and immediately after giving effect to such
     transaction on a pro forma basis (and treating any Indebtedness which
     becomes an obligation of the Company (or the Successor Corporation if the
     Company is not the continuing obligor under the Indenture) or any
     Restricted Subsidiary as a result of such transaction as having been
     Incurred by such Person at the time of such transaction), no Default shall
     have occurred and be continuing;
 
          (iii) the Company shall have delivered, or caused to be delivered, to
     the Trustee an Officers' Certificate and, as to legal matters, an Opinion
     of Counsel, each in form and substance reasonably satisfactory to the
     Trustee, each stating that such consolidation, merger or transfer and such
     supplemental indenture comply with the Indenture and that all conditions
     precedent herein provided for relating to such transaction have been
     complied with;
 
          (iv) immediately after giving effect to such transaction on a pro
     forma basis (and treating any Indebtedness which becomes an obligation of
     the Company (or the Successor Corporation if the Company is not the
     continuing obligor under the Indenture) or a Restricted Subsidiary in
     connection with or as a result of such transaction as having been Incurred
     by such Person at the time of such transaction), the Company (or the
     Successor Corporation if the Company is not the continuing obligor under
     the Indenture) shall have a Consolidated Net Worth in an amount which is
     not less than the Consolidated Net Worth of the Company immediately prior
     to such transaction; and
 
          (v) immediately after giving effect to such transaction on a pro forma
     basis (and treating any Indebtedness which becomes an obligation of the
     Company (or the Successor Corporation if the Company is not the continuing
     obligor under the Indenture) or a Restricted Subsidiary in connection with
     or as a result of such transaction as having been Incurred by such Person
     at the time of such transaction), the Consolidated Coverage Ratio of the
     Company (or the Successor Corporation if the Company is not the continuing
     obligor under the Indenture) is at least 1.10:1, or, if less, equal to the
     Consolidated Coverage Ratio of the Company immediately prior to such
     transaction; provided that, if the Consolidated Coverage Ratio of the
     Company before giving effect to such transaction is within the range set
     forth in column (A) below, then the pro forma Consolidated Coverage Ratio
     of the Company (or the Successor Corporation if the Company is not the
     continuing obligor under the
 
                                       48
<PAGE>   131
 
     Indenture) shall be at least equal to the lesser of (1) the ratio
     determined by multiplying the percentage set forth in column (B) below by
     the Consolidated Coverage Ratio of the Company prior to such transaction
     and (2) the ratio set forth in column (C) below:
 
<TABLE>
<CAPTION>
                   (A)                     (B)     (C)
                   ---                     ---    -----
<S>                                        <C>    <C>
1.11:1 to 1.99:1.........................  100%   1.6:1
2.00:1 to 2.99:1.........................   90%   2.1:1
3.00:1 to 3.99:1.........................   80%   2.4:1
4.00:1 or more...........................   70%   2.5:1
</TABLE>
 
     Notwithstanding the foregoing clauses (ii), (iv) and (v), any Restricted
Subsidiary (other than a Subsidiary having an interest in a Facility) may
consolidate with, merge into or transfer all or part of its properties and
assets to the Company or any Wholly Owned Subsidiary or Wholly Owned
Subsidiaries (other than a Subsidiary or Subsidiaries which have an interest in
a Facility) and no violation of this provision will be deemed to have occurred
as a consequence thereof, as long as the requirements of clauses (i) and (iii)
are satisfied in connection therewith.
 
     Upon any such assumption by the Successor Corporation, except in the case
of a lease, the Successor Corporation shall succeed to and be substituted for
the Company under the Indenture and the Notes and the Company shall thereupon be
released from all obligations under the Indenture and under the Notes and the
Company as the predecessor corporation may thereupon or at any time thereafter
be dissolved, wound up or liquidated. The Successor Corporation thereupon may
cause to be signed, and may issue either in its own name or in the name of the
Company, all or any of the Notes issuable under the Indenture which theretofore
shall not have been signed by the Company and delivered to the Trustee; and,
upon the order of the Successor Corporation instead of the Company and subject
to all the terms, conditions and limitations prescribed in the Indenture, the
Trustee shall authenticate and shall deliver any Notes which the Successor
Corporation thereafter shall cause to be signed and delivered to the Trustee for
that purpose. All the Notes so issued shall in all respects have the same legal
rank and benefit under the Indenture as the Notes theretofore or thereafter
issued in accordance with the terms of the Indenture as though all such Notes
had been issued at the date of the execution of the Indenture.
 
     In the case of any such consolidation, merger or transfer, such changes in
form (but not in substance) may be made in the Notes thereafter to be issued as
may be appropriate.
 
EVENTS OF DEFAULT
 
     "Events of Default" are defined in the Indenture as
 
          (a) default for 30 days in payment of any interest installment due and
     payable on the Notes,
 
          (b) default in payment of the principal when due on any Note, or
     failure to purchase Notes when required pursuant to the Indenture or the
     Notes,
 
          (c) default in performance of any other covenants or agreements in the
     Indenture or in the Notes for 30 days after written notice to the Company
     by the Trustee or to the Company and the Trustee by the holders of at least
     25% in principal amount of the Notes then outstanding,
 
                                       49
<PAGE>   132
 
          (d) there shall have occurred either (i) a default by the Company or
     any Subsidiary under any instrument or instruments under which there is or
     may be secured or evidenced any Indebtedness of the Company or any
     Subsidiary of the Company (other than the Notes) having an outstanding
     principal amount of $2,000,000 (or its foreign currency equivalent) or more
     individually or $5,000,000 (or its foreign currency equivalent) or more in
     the aggregate that has caused the holders thereof to declare such
     Indebtedness to be due and payable prior to its Stated Maturity or (ii) a
     default by the Company or any Subsidiary in the payment when due of any
     portion of the principal under any such instrument, and such unpaid portion
     exceeds $2,000,000 (or its foreign currency equivalent) individually or
     $5,000,000 (or its foreign currency equivalent) in the aggregate and is not
     paid, or such default is not cured or waived, within any grace period
     applicable thereto, unless such Indebtedness is discharged within 20 days
     of the Company or a Restricted Subsidiary becoming aware of such default;
     provided, however, that the foregoing shall not apply to any default on
     Non-Recourse Indebtedness;
 
          (e) any final judgment or order (not covered by insurance) for the
     payment of money shall be rendered against the Company or any Significant
     Subsidiary in an amount in excess of $2,000,000 (or its foreign currency
     equivalent) individually or $5,000,000 (or its foreign currency equivalent)
     in the aggregate for all such final judgments or orders against all such
     Persons (treating any deductibles, self-insurance or retention as not so
     covered) and shall not be discharged, and there shall be any period of 30
     consecutive days following entry of the final judgment or order in excess
     of $2,000,000 (or its foreign currency equivalent) individually or that
     causes the aggregate amount for all such final judgments or orders
     outstanding against all such Persons to exceed $5,000,000 (or its foreign
     currency equivalent) during which a stay of enforcement of such final
     judgment or order, by reason of a pending appeal or otherwise, shall not be
     in effect; and
 
          (f) certain events of bankruptcy, insolvency and reorganization of the
     Company.
 
     If any Event of Default (other than an Event of Default described in clause
(f) with respect to the Company) occurs and is continuing, the Indenture
provides that the Trustee by notice to the Company, or the Holders of at least
25% in principal amount of the Notes by notice to the Company and the Trustee,
may declare the principal amount of the Notes and any accrued and unpaid
interest to be due and payable immediately. If an Event of Default described in
clause (f) with respect to the Company occurs, the principal of and interest on
all the Notes shall ipso facto become and be immediately due and payable without
any declaration or other act on the part of the Trustee or any Holders of Notes.
The Holders of a majority in principal amount of the Notes by notice to the
Trustee may rescind any such declaration and its consequences if the rescission
would not conflict with any judgment or decree and if all existing Events of
Default have been cured or waived other than the non-payment of principal of or
interest on the Notes which shall have become due by such declaration.
 
     The Company must file annually with the Trustee a certificate describing
any Default by the Company in the performance of any conditions or covenants
that has occurred under the Indenture and its status. The Company must give the
Trustee written notice within 30 days of any Default under the Indenture that
could mature into an Event of Default described in clause (c), (d), (e) or (f)
of the second preceding paragraph.
 
                                       50
<PAGE>   133
 
     The Trustee is entitled, subject to the duty of the Trustee during a
Default to act with the required standard of care, to be indemnified before
proceeding to exercise any right or power under the Indenture at the direction
of the Holders of the Notes or which requires the Trustee to expend or risk its
own funds or otherwise incur any financial liability. The Indenture also
provides that the Holders of a majority in principal amount of the Notes issued
under the Indenture may direct the time, method and place of conducting any
proceeding for any remedy available to the Trustee or exercising any trust or
power conferred on the Trustee; however, the Trustee may refuse to follow any
such direction that conflicts with law or the Indenture, is unduly prejudicial
to the rights of other Holders of the Notes, or would involve the Trustee in
personal liability.
 
     The Indenture provides that while the Trustee generally must mail notice of
a Default or Event of Default to the holders of the Notes within 90 days of
occurrence, the Trustee may withhold notice to the Holders of the Notes of any
Default or Event of Default (except in payment on the Notes) if the Trustee in
good faith determines that the withholding of such notice is in the interest of
the Holders of the Notes.
 
MODIFICATION OF THE INDENTURE
 
     Under the terms of the Indenture, the Company and the Trustee may, with the
consent of the Holders of a majority in principal amount of the outstanding
Notes amend or supplement the Indenture or the Notes except that no amendment or
supplement may, without the consent of each affected Holder,
 
          (i) reduce the principal of or change the Stated Maturity of any Note,
 
          (ii) reduce the rate of or change the time of payment of interest on
     any Note,
 
          (iii) change the currency of payment of the Notes,
 
          (iv) provide that the Notes will be redeemable prior to maturity,
 
          (v) reduce the amount of Notes, the holders of which must consent to
     an amendment or supplement or
 
          (vi) change the provisions of the Indenture relating to waiver of past
     defaults, rights of Holders of the Notes to receive payments or the
     provisions relating to amendments of the Indenture that require the consent
     of Holders of each affected Note.
 
ACTIONS BY NOTEHOLDERS
 
     Under the terms of the Indenture, a Holder of Notes may not pursue any
remedy with respect to the Indenture or the Notes (except actions for payment of
overdue principal or interest), unless
 
          (i) the Holder has given notice to the Trustee of a continuing Event
     of Default,
 
          (ii) Holders of at least 25% in principal amount of the Notes have
     made a written request to the Trustee to pursue such remedy,
 
          (iii) such Holder or Holders have offered the Trustee security or
     indemnity reasonably satisfactory to it against any loss, liability or
     expense,
 
                                       51
<PAGE>   134
 
          (iv) the Trustee has not complied with such request within 60 days of
     such request and offer and
 
          (v) the Holders of a majority in principal amount of the Notes have
     not given the Trustee an inconsistent direction during such 60-day period.
 
DEFEASANCE, DISCHARGE AND TERMINATION
 
     Defeasance and Discharge. The Indenture provides that the Company will be
discharged from any and all obligations in respect of the Notes, and the
provisions of the Indenture will no longer be in effect with respect to such
Notes (except for, among other matters, certain obligations to register the
transfer or exchange of such Notes, to replace stolen, lost or mutilated Notes,
to maintain paying agencies and to hold monies for payment in trust, and the
rights of holders to receive payments of principal and interest thereon), on the
123rd day after the date of the deposit with the Trustee, in trust, of money or
U.S. Government Obligations that, through the payment of interest and principal
in respect thereof in accordance with their terms, will provide money, or a
combination thereof, in an amount sufficient to pay the principal of and
interest on such Notes, when due in accordance with the terms of the Indenture
and such Notes. Such a trust may only be established if, among other things,
 
          (i) the Company has delivered to the Trustee either
 
             (a) an Opinion of Counsel (who may not be employed by the Company)
        to the effect that Holders will not recognize income, gain or loss for
        federal income tax purposes as a result of such deposit, defeasance and
        discharge and will be subject to federal income tax on the same amount
        and in the same manner and at the same times as would have been the case
        if such deposit, defeasance and discharge had not occurred, which
        Opinion of Counsel must refer to and be based upon a ruling of the
        Internal Revenue Service or a change in applicable federal income tax
        law occurring after the date of the Indenture or
 
             (b) a ruling of the Internal Revenue Service to such effect, and
 
          (ii) no Default under the Indenture shall have occurred and be
     continuing on the date of such deposit or during the period ending on the
     123rd day after such date of deposit and such deposit shall not result in
     or constitute a Default or result in a breach or violation of, or
     constitute a default under, any other agreement or instrument to which the
     Company is a party or by which the Company is bound.
 
     Defeasance of Certain Covenants and Certain Events of Default. The
Indenture further provides that the provisions of the Indenture will no longer
be in effect with respect to the provisions described in clauses (iv) and (v)
under "-- Merger and Consolidation" and all the covenants described herein under
"-- Covenants," clause (c) under "-- Events of Default" with respect to such
covenants and clauses (iv) and (v) under "-- Merger and Consolidation," and
clauses (d) and (e) under "-- Events of Default" shall be deemed not to be
Events of Default under the Indenture, and the provisions described herein under
"-- Ranking" shall not apply, upon the deposit with the Trustee, in trust, of
money or U.S. Government Obligations that through the payment of interest and
principal in respect thereof in accordance with their terms will provide money
in an amount sufficient to pay the principal of and interest on the Notes issued
thereunder when due in accordance with the terms of the Indenture. Such a trust
may only be established if, among other things, the provisions described in
clause (ii) of the immediately preceding paragraph have been
 
                                       52
<PAGE>   135
 
satisfied and the Company has delivered to the Trustee an Opinion of Counsel
(who may not be an employee of the Company) to the effect that the Holders will
not recognize income, gain or loss for federal income tax purposes as a result
of such deposit and defeasance of certain covenants and Events of Default and
will be subject to federal income tax on the same amount and in the same manner
and at the same times as would have been the case if such deposit and defeasance
had not occurred.
 
     Defeasance and Certain Other Events of Default. In the event the Company
exercises its option to omit compliance with certain covenants and provisions of
the Indenture with respect to the Notes, as described in the immediately
preceding paragraph and such Notes are declared due and payable because of the
occurrence of an Event of Default that remains applicable, the amount of money
or U.S. Government Obligations on deposit with the Trustee will be sufficient to
pay principal of and interest on Notes on the respective dates on which such
amounts are due but may not be sufficient to pay amounts due on such Notes, at
the time of the acceleration resulting from such Event of Default. However, the
Company shall remain liable for such payments.
 
     Termination of Company's Obligations in Certain Circumstances. The
Indenture further provides that the Company will be discharged from any and all
obligations in respect of the Notes and the provisions of such Indenture will no
longer be in effect with respect to the Notes (except to the extent provided
under "-- Defeasance and Discharge") if such Notes mature within one year and
the Company deposits with the Trustee, in trust, money or U.S. Government
Obligations that, through the payment of interest and principal in respect
thereof in accordance with their terms, will provide money in an amount
sufficient to pay the principal of, premium, if any, and accrued interest on
such Notes when due in accordance with the terms of the Indenture and such
Notes. Such a trust may only be established if, among other things,
 
          (i) no Default under the Indenture shall have occurred and be
     continuing on the date of such deposit,
 
          (ii) such deposit will not result in or constitute a Default or result
     in a breach or violation of, or constitute a Default under, any other
     agreement or instrument to which the Company is a party or by which it is
     bound and
 
          (iii) the Company has delivered to the Trustee an Opinion of Counsel
     stating that such conditions have been complied with.
 
     Pursuant to this provision, the Company is not required to deliver an
Opinion of Counsel to the effect that Holders will not recognize income, gain or
loss for U.S. federal income tax purposes as a result of such deposit and
termination, and there is no assurance that Holders would not recognize income,
gain or loss for U.S. federal income tax purposes as a result thereof or that
Holders would be subject to U.S. federal income tax on the same amount and in
the same manner and at the same times as would have been the case if such
deposit and termination had not occurred.
 
UNCLAIMED MONEY
 
     Under the terms of the Indenture, subject to any applicable abandoned
property law, the Trustee will pay to the Company upon request any money held by
it for the payment of principal or interest that remains unclaimed for two
years. After payment to the Company, Holders of Notes entitled to such money
must look to the Company for payment as general creditors.
 
                                       53
<PAGE>   136
 
CONCERNING THE TRUSTEE AND PAYING AGENT
 
     The Bank of New York will act as Trustee under the Indenture and will
initially be Paying Agent and Registrar for the Notes. The Company may have in
the future other relationships with such bank. Notices to the Trustee, Paying
Agent and Registrar under the Indenture should be directed to The Bank of New
York, 101 Barclay Street, 21st Floor, New York, New York 10286, Attention:
Corporate Trust Trustee Administration.
 
GOVERNING LAW
 
     Under the terms of the Indenture, the laws of the State of New York govern
the Indenture and the Notes.
 
BOOK-ENTRY SYSTEM
 
     The Notes will be represented by one or more Global Notes (collectively,
the "Global Note") registered in the name of a nominee of The Depository Trust
Company, as Depositary ("DTC"). Upon the issuance of the Global Note (each a
"Global Note" and together the "Global Notes"), DTC or its custodian will
credit, on its internal system, the respective principal amount of the
individual beneficial interests represented by such Global Note to the accounts
of persons who have accounts with such depositary. Such accounts initially will
be designated by or on behalf of the underwriters, dealer or agents. Ownership
of beneficial interests in a Global Note will be limited to persons who have
accounts with DTC ("participants") or persons who hold interests through
participants. Ownership of beneficial interests in the Global Note will be shown
on, and the transfer of that ownership will be effected only through, records
maintained by DTC or its nominee (with respect to interests of participants) and
the records of participants (with respect to interests of persons other than
participants).
 
     So long as DTC, or its nominee, is the registered owner or holder of a
Global Note, DTC or such nominee, as the case may be, will be considered the
sole owner or holder of the Notes represented by such Global Note for all
purposes under the Indenture and the Notes. No beneficial owner of an interest
in a Global Note will be able to transfer that interest except in accordance
with DTC's applicable procedures, in addition to those provided for under the
Indenture.
 
     Payments of the principal of, and interest on, the Global Notes will be
made to DTC or its nominee, as the case may be, as the registered owner thereof.
Neither the Company, the Trustee nor any Paying Agent will have any
responsibility or liability for any aspect of the records relating to or
payments made on account of beneficial ownership interests in the Global Notes
or for maintaining, supervising or reviewing any records relating to such
beneficiary ownership interests.
 
     The Company expects that DTC or its nominee, upon receipt of any payment of
principal or interest in respect of a Global Note will credit participants'
accounts with payments in amounts proportionate to their respective beneficial
interests in the principal amount of such Global Note as shown on the records of
DTC or its nominee. The Company also expects that payments by participants to
owners of beneficial interests in such Global Note held through such
participants will be governed by standing instructions and customary practices,
as is now the case with securities held for the accounts of
 
                                       54
<PAGE>   137
 
customers registered in the names of nominees for such customers. Such payments
will be the responsibility of such participants.
 
     Transfers between participants in DTC will be effected in the ordinary way
in accordance with DTC rules and will be settled in same-day funds. If a holder
requires physical delivery of a Certificated Note for any reason, including to
sell Notes to persons in states which require such delivery of such Notes or to
pledge such Notes, such holder must transfer its interest in the Global Note in
accordance with the normal procedures of DTC and the procedures set forth in the
Indenture.
 
     DTC has advised the Company that it will take any action permitted to be
taken by a holder of Notes (including the presentation of Notes for exchange as
described below) only at the direction of one or more participants to whose
account the DTC interests in the Global Note is credited and only in respect of
such portion of the aggregate principal amount of Notes as to which such
participant or participants has or have given such direction. However, if there
is an Event of Default under the Notes, DTC will exchange the Global Note for
Certificated Notes which it will distribute to its participants.
 
     DTC has advised the Company as follows: DTC is a limited purpose trust
company organized under the laws of the State of New York, a "banking
organization" within the meaning of New York Banking Law, a member of the
Federal Reserve System, a "clearing corporation" within the meaning of the
Uniform Commercial Code and a "Clearing Agency" registered pursuant to the
provisions of Section 17A of the Securities Exchange Act of 1934. DTC was
created to hold securities for its participants and facilitate the clearance and
settlement of securities transactions between participants through electronic
book-entry changes in accounts of its participants, thereby eliminating the need
for physical movement of certificates. Participants include securities brokers
and dealers, banks, trust companies and clearing corporations and certain other
organizations. Indirect access to the DTC system is available to others such as
banks, brokers, dealers and trust companies that clear through or maintain a
custodial relationship with a participant, either directly or indirectly
("indirect participants").
 
     Although DTC has agreed to the foregoing procedures in order to facilitate
transfers of interest in the Global Note among participants of DTC, it is under
no obligation to perform or continue to perform such procedures, and such
procedures may be discontinued at any time. Neither the Company nor the Trustee
will have any responsibility for the performance by DTC or its respective
participants or indirect participants of their respective obligations under the
rules and procedures governing their operations.
 
CERTIFICATED NOTES
 
     If DTC is at any time unwilling or unable to continue as a depositary for
the Global Note and a successor depositary is not appointed by the Company
within 90 days, the Company will issue Certificated Notes in exchange for the
Global Note.
 
                                       55
<PAGE>   138
 
                   DESCRIPTION OF CERTAIN OTHER INDEBTEDNESS
 
7 7/8% SENIOR NOTES DUE 2008
 
     On March 31, 1998 and July 24, 1998, we issued $300.0 million and $100.0
million, respectively, aggregate principal amount of 7 7/8% Senior Notes. The
7 7/8% Senior Notes are senior unsecured obligations of our company and rank
equal with our other senior notes, including the Senior Notes being offered
pursuant to this prospectus.
 
     The 7 7/8% Senior Notes bear interest at a rate of 7 7/8% per annum payable
semi-annually on April 1 and October 1 of each year and mature on April 1, 2008.
The 7 7/8% Senior Notes are not subject to redemption prior to maturity.
 
     Upon a Change of Control Triggering Event (as defined in the 7 7/8%
Indenture), each holder of 7 7/8% Senior Notes will have the right to require us
to repurchase such 7 7/8% Senior Notes at 101% of the principal amount thereof
plus accrued and unpaid interest to the repurchase date. The Revolving Credit
Facility limits our ability to redeem the 7 7/8% Senior Notes.
 
     Similar to the indentures governing the Senior Notes being offered pursuant
to this prospectus (and subject to similar qualifications), the 7 7/8% Indenture
contains certain covenants that, among other things, limit (1) the incurrence of
additional debt by us and our subsidiaries, (2) the payment of dividends on and
redemptions of capital stock by us and our subsidiaries, (3) the use of proceeds
from the sale of assets and subsidiary stock, (4) transactions with affiliates,
(5) the incurrence of liens, (6) sale and leaseback transactions and (7)
consolidations, mergers and certain transfers of assets.
 
     The foregoing summary describes certain provisions of the 7 7/8% Indenture
and the 7 7/8% Senior Notes, a copy of each of which is available upon request
made to us. The foregoing summary does not purport to be complete and is subject
to and is qualified in its entirety by reference to the 7 7/8% Indenture and the
form of 7 7/8% Senior Notes.
 
8 3/4% SENIOR NOTES DUE 2007
 
     On July 8, 1997 and September 10, 1997, we issued $200.0 million and $75.0
million, respectively, aggregate principal amount of 8 3/4% Senior Notes. The
8 3/4% Senior Notes are senior unsecured obligations of our company and rank
equal with our other senior notes, including the Senior Notes being offered
pursuant to this prospectus.
 
     The 8 3/4% Senior Notes bear interest at a rate of 8 3/4% per annum payable
semi-annually on January 15 and July 15 of each year and mature on July 15,
2007. The 8 3/4% Senior Notes are redeemable at our option, in whole or in part,
at any time after July 15, 2002 at the various redemption prices set forth in
the 8 3/4% Indenture, plus accrued interest to the date of redemption. In
addition, prior to July 15, 2000, up to $70.0 million of the 8 3/4% Senior Notes
may be redeemed at 108.75% of the principal amount thereof, plus accrued
interest, with the net proceeds of one or more public equity offerings by us.
 
     Upon a Change of Control Triggering Event (as defined in the 8 3/4%
Indenture), each holder of 8 3/4% Senior Notes will have the right to require us
to repurchase such 8 3/4% Senior Notes at 101% of the principal amount thereof
plus accrued and unpaid interest to the repurchase date. The Revolving Credit
Facility limits our ability to redeem the 8 3/4% Senior Notes.
                                       56
<PAGE>   139
 
     Similar to the indentures governing the Senior Notes being offered pursuant
to this prospectus (and subject to similar qualifications), the 8 3/4% Indenture
contains certain covenants that, among other things, limit (i) the incurrence of
additional debt by us and our subsidiaries, (ii) the payment of dividends on and
redemptions of capital stock by us and our subsidiaries, (iii) the use of
proceeds from the sale of assets and subsidiary stock, (iv) transactions with
affiliates, (v) the incurrence of liens, (vi) sale and leaseback transactions
and (vii) consolidations, mergers and certain transfers of assets.
 
     The foregoing summary describes certain provisions of the 8 3/4% Indenture
and the 8 3/4% Senior Notes, a copy of each of which is available upon request
made to us. The foregoing summary does not purport to be complete and is subject
to and is qualified in its entirety by reference to the 8 3/4% Indenture and the
form of 8 3/4% Senior Notes.
 
10 1/2% SENIOR NOTES DUE 2006
 
     On May 16, 1996, we issued $180.0 million aggregate principal amount of
10 1/2% Senior Notes. The 10 1/2% Senior Notes are senior unsecured obligations
of our company and will rank equal with our other senior notes, including the
Senior Notes being offered pursuant to this prospectus.
 
     The 10 1/2% Senior Notes bear interest at a rate of 10 1/2% per annum
payable semi-annually on May 15, and November 15 of each year and mature on May
15, 2006. The 10 1/2% Senior Notes are redeemable at our option, in whole or in
part, at any time after May 15, 2001 at the various redemption prices set forth
in the 10 1/2% Indenture, plus accrued interest to the date of redemption. In
addition, prior to May 15, 1999, up to $63.0 million of 10 1/2% Senior Notes may
be redeemed at 110.50% of the principal amount thereof, plus accrued interest,
with the net proceeds of one or more public equity offerings by us.
 
     Upon a Change of Control Triggering Event (as defined in the 10 1/2%
Indenture), each holder of 10 1/2% Senior Notes will have the right to require
us to repurchase such 10 1/2% Senior Notes at 101% of the principal amount
thereof plus accrued and unpaid interest to the repurchase date. The Revolving
Credit Facility limits our ability to redeem the 10 1/2% Senior Notes.
 
     Similar to the indentures governing the Senior Notes being offered pursuant
to this prospectus (and subject to similar qualifications), the 10 1/2%
Indenture contains certain covenants that, among other things, limit (1) the
incurrence of additional debt by us and our subsidiaries, (2) the payment of
dividends on and redemptions of capital stock by us and our subsidiaries, (3)
the use of proceeds from the sale of assets and subsidiary stock, (4)
transactions with affiliates, (5) the incurrence of liens, (6) sale and
leaseback transactions and (7) consolidations, mergers and certain transfers of
assets.
 
     The foregoing summary describes certain provisions of the 10 1/2% Indenture
and the 10 1/2% Senior Notes, a copy of each of which is available upon request
made to us. The foregoing summary does not purport to be complete and is subject
to and is qualified in its entirety by reference to the 10 1/2% Indenture and
the form of 10 1/2% Senior Notes.
 
9 1/4% SENIOR NOTES DUE 2004
 
     On February 17, 1994, we issued $105.0 million aggregate principal amount
of 9 1/4% Senior Notes in an underwritten public offering. The 9 1/4% Senior
Notes are senior
 
                                       57
<PAGE>   140
 
unsecured obligations of our company and will rank equal with our other senior
notes, including the Senior Notes being offered pursuant to this prospectus.
 
     The 9 1/4% Senior Notes bear interest at a rate of 9 1/4% per annum payable
semi-annually on February l and August l of each year and mature on February 1,
2004. The 9 1/4% Senior Notes are redeemable at our option, in whole or in part,
at any time after February 1, 1999 at the various redemption prices set forth in
the 9 1/4% Indenture, plus accrued interest to the date of redemption.
 
     Upon a Change of Control Triggering Event (as defined in the 9 1/4%
Indenture), each holder of 9 1/4% Senior Notes will have the right to require us
to repurchase such 9 1/4% Senior Notes at 101% of the principal amount thereof
plus accrued and unpaid interest to the repurchase date. The Revolving Credit
Facility limits our ability to redeem the 9 1/4% Senior Notes.
 
     Similar to the indentures governing the Senior Notes being offered pursuant
to this prospectus (and subject to similar qualifications), the 9 1/4% Indenture
contains certain covenants that, among other things, limit (1) the incurrence of
additional debt by us and our subsidiaries, (2) the payment of dividends on and
redemptions of capital stock by us and our subsidiaries, (3) the use of proceeds
from the sale of assets and subsidiary stock, (4) transactions with affiliates,
(5) the incurrence of liens, (6) sale and leaseback transactions and (7)
consolidations, mergers and certain transfers of assets.
 
     The foregoing summary describes certain provisions of the 9 1/4% Indenture
and the 9 1/4% Senior Notes, a copy of each of which is available upon request
made to us. The foregoing summary does not purport to be complete and is subject
to and is qualified in its entirety by reference to the 9 1/4% Indenture and the
form of 9 1/4% Senior Notes.
 
OTHER
 
     See "Business -- Description of Facilities" and "Management's Discussion
and Analysis of Financial Condition and Results of Operations" for a description
of our other indebtedness, including the Revolving Credit Facility.
 
                                       58
<PAGE>   141
 
                   CERTAIN FEDERAL INCOME TAX CONSIDERATIONS
 
     The discussion set forth in this summary is based on the provisions of the
Internal Revenue Code of 1986, as amended (the "Code"), final, temporary and
proposed Treasury regulations thereunder and administrative and judicial
interpretations thereof, all as in effect on the date hereof and all of which
are subject to change (possibly on a retroactive basis).
 
     This summary is for general information only and does not purport to
address all of the federal income tax consequences that may be applicable to a
holder of Senior Notes. The tax treatment of a holder of Senior Notes may vary
depending on its particular situation. For example, certain holders, including
individual retirement and other tax-deferred accounts, insurance companies,
tax-exempt organizations, financial institutions and broker-dealers, may be
subject to special rules not discussed below. This discussion addresses the tax
consequences to the initial holders of the Senior Notes which hold the Senior
Notes as a capital asset.
 
     EACH HOLDER SHOULD CONSULT ITS OWN TAX ADVISOR WITH RESPECT TO THE FEDERAL
INCOME TAX CONSEQUENCES SET FORTH BELOW AND ANY OTHER FEDERAL, STATE, LOCAL OR
FOREIGN TAX CONSEQUENCES OF ACQUIRING, HOLDING AND DISPOSING OF THE SENIOR
NOTES.
 
UNITED STATES HOLDERS
 
     In this discussion, "United States holder" means: (1) a citizen or resident
of the United States; (2) a corporation, partnership or other entity created or
organized under the laws of the United States or of any state; (3) an estate,
the income of which is subject to United States federal income taxation
regardless of its source; or (4) a trust, the administration of which is subject
to the primary supervision of a United States court and the control of all the
substantial decisions of which is within the authority of one or more United
States persons.
 
STATED INTEREST
 
     A United States holder of a Senior Note will be required to report as
income for federal income tax purposes interest earned on a Senior Note in
accordance with the United States holder's method of tax accounting. A United
States holder of a Senior Note using the accrual method of accounting for tax
purposes is, as a general rule, required to include interest in ordinary income
as such interest accrues, while a cash basis United States holder must include
interest income when cash payments are received (or made available for receipt)
by such holder.
 
ORIGINAL ISSUE DISCOUNT
 
     If the Senior Notes are issued with original issue discount ("OID") within
the meaning of Sections 1272 and 1273 of the Code and the pertinent Treasury
Regulations, United States holders of the Senior Notes generally will be
required to include such OID in gross income as it accrues. The total amount of
OID, if any, with respect to each Senior Note will be any excess of its "stated
redemption price at maturity" over its "issue price"; provided that a Senior
Note will be deemed not to have OID if such excess is less than 1/4 of 1% of the
Senior Note's stated redemption price at maturity multiplied by the number
                                       59
<PAGE>   142
 
of complete years to its maturity from its issue date. The "issue price" of the
Senior Notes (or a particular issue of Senior Notes) generally will be the first
price at which a substantial amount of such Senior Notes are sold. The "stated
redemption price at maturity" of the Senior Notes will be the sum of all
payments provided by the Senior Notes other than "qualified stated interest"
payments. The term "qualified stated interest" generally means stated interest
that is unconditionally payable in cash or property (other than debt instruments
of the issuer) at least annually at a single fixed rate. A United States holder
of a Senior Note issued with OID would be required to include the OID in income
for federal income tax purposes as it accrues under a "constant yield method,"
regardless of such United States holder's method of accounting for tax purposes.
To the extent required by applicable law, we will furnish to the IRS and to
record United States holders of the Senior Notes information with respect to the
OID, if any, accruing during the calendar year (as well as interest paid during
that year).
 
SALE, EXCHANGE OR OTHER TAXABLE DISPOSITION OF A SENIOR NOTE
 
     Upon the sale, exchange or other taxable disposition of a Senior Note, a
United States holder will recognize taxable gain or loss equal to the difference
between (1) the amount of cash and the fair market value of property received
(other than amounts received attributable to interest not previously taken into
account, which amount will be treated as interest received), and (2) the United
States holder's adjusted tax basis in the Senior Note. A United States holder's
adjusted tax basis in a Senior Note generally will equal the cost of the Senior
Note to the United States holder, increased by the amount of any OID previously
included in income by the holder with respect to the Senior Note and reduced by
any payments previously received by the holder with respect to the Senior Note,
other than qualified stated interest payments, and by any premium amortization
deductions previously claimed by the holder. Provided that the Senior Note has
been held for more than one year, any gain or loss recognized by the holder will
generally be a long-term capital gain or loss.
 
NON-UNITED STATES HOLDERS
 
INTEREST AND OID
 
     In general, payments of interest (including any OID) received or accrued by
a holder of a Senior Note that is not a United States holder (a "non-United
States holder") will not be subject to United States federal withholding tax,
provided that:
 
     (1) (a) the non-United States holder does not actually or constructively
             own 10% or more of the total combined voting power of all classes
             of our stock entitled to vote,
 
        (b) the non-United States holder is not a controlled foreign corporation
            that is related to us actually or constructively through stock
            ownership, and
 
        (c) the beneficial owner of the Senior Note, under penalty of perjury,
            either directly or through a financial institution which holds the
            Senior Note on behalf of the non-United States holder and holds
            customers' securities in the ordinary course of its trade or
            business, provides us or our agent with the beneficial owner's name
            and address and certifies, under penalty of perjury, that it is not
            a United States person;
 
                                       60
<PAGE>   143
 
     (2) the interest received on the Senior Note is effectively connected with
         the conduct by the non-United States holder of a trade or business
         within the United States and the non-United States holder complies with
         certain reporting requirements; or
 
     (3) the non-United States holder is entitled to the benefits of an income
         tax treaty under which the interest is exempt from United States
         withholding tax and the non-United States holder complies with certain
         reporting requirements.
 
Payments of interest not exempt from United States federal withholding tax as
described above will be subject to such withholding tax at the rate of 30%
(subject to reduction under an applicable income tax treaty).
 
SALE, EXCHANGE OR OTHER TAXABLE DISPOSITION OF THE SENIOR NOTES
 
     A non-United States holder generally will not be subject to United States
federal income tax (and generally no tax will be withheld) with respect to gain
realized or recognized on the sale, exchange or other taxable disposition of a
Senior Note, unless:
 
     (1) the gain is effectively connected with a United States trade or
         business conducted by the non-United States holder;
 
     (2) the non-United States holder is an individual who is present in the
         United States for 183 or more days during the taxable year of the
         disposition and certain other requirements are satisfied; or
 
     (3) the gain is subject to federal income tax pursuant to federal income
         tax laws applicable to certain expatriates.
 
EFFECTIVELY CONNECTED INCOME
 
     If interest and other payments received by a non-United States holder with
respect to the Senior Notes (including proceeds from the disposition of the
Senior Notes) are effectively connected with the conduct by the non-United
States holder of a trade or business within the United States (or the non-United
States holder is otherwise subject to United States federal income taxation on a
net basis with respect to such holder's ownership of the Senior Notes), such
non-United States holder will generally be subject to the rules described above
under "-- United States Holders" (subject to any modification provided under an
applicable income tax treaty). Such non-United States holder may also be subject
to the "branch profits tax" if such holder is a corporation.
 
BACKUP WITHHOLDING AND INFORMATION REPORTING
 
     Certain non-corporate United States holders may be subject to backup
withholding at a rate of 31% on payments of principal, premium and interest on,
and the proceeds of the disposition of, the Senior Notes. In general, backup
withholding will be imposed only if the United States holder: (1) fails to
furnish its taxpayer identification number ("TIN"), which, for an individual,
would be his or her Social Security number, (2) furnishes an incorrect TIN, (3)
is notified by the IRS that it has failed to report payments of interest or
dividends or (4) under certain circumstances, fails to certify, under penalty of
perjury, that is has furnished a correct TIN and has been notified by the IRS
that is subject to backup withholding tax for failure to report interest or
dividend payments. In addition,
 
                                       61
<PAGE>   144
 
such payments of principal and interest to United States holders will generally
be subject to information reporting. United States holders should consult their
tax advisors regarding their qualification for exemption from backup withholding
and the procedure for obtaining such an exemption, if applicable.
 
     Backup withholding generally will not apply to payments made to a
non-United States holder of a Senior Note which provides the certification
described under "Non-United States Holders -- Interest and OID" or otherwise
establishes an exemption from backup withholding. Payments by a United States
office of a broker of the proceeds of a disposition of the Senior Notes
generally will be subject to backup withholding at a rate of 31% unless the
non-United States holder certifies that it is a non-United States person under
penalty of perjury or otherwise establishes an exemption.
 
     The amount of any backup withholding imposed on a payment to a holder of a
Senior Note will be allowed as a credit against such holder's United States
federal income tax liability and may entitle such holder to a refund, provided
that the required information is furnished to the IRS.
 
NEW TREASURY REGULATIONS
 
     New final Treasury regulations governing information reporting and the
certification procedures regarding withholding and backup withholding on certain
amounts paid to non-United States holders after December 31, 1999 generally
would not alter the treatment of non-United States holders described above. The
new Treasury regulations would alter the procedures for claiming the benefits of
an income tax treaty and may change the certification procedures relating to the
receipt by intermediaries of payments on behalf of a beneficial owner of a
Senior Note. Holders should consult their tax advisors concerning the effect, if
any, of such new Treasury regulations on an investment in the Senior Notes.
 
                                       62
<PAGE>   145
 
                                  UNDERWRITING
 
     Under the terms and subject to the conditions contained in an underwriting
agreement, dated                             , 1999, we have agreed to sell to
the underwriters named below, for whom Credit Suisse First Boston Corporation
and                are acting as representatives, the following respective
principal amounts of the Senior Notes set forth opposite the name of such
underwriter:
 
<TABLE>
<CAPTION>
                                 PRINCIPAL   PRINCIPAL   PRINCIPAL   PRINCIPAL
                                 AMOUNT OF   AMOUNT OF   AMOUNT OF   AMOUNT OF
          UNDERWRITER             % NOTES     % NOTES     % NOTES     % NOTES
          -----------            ---------   ---------   ---------   ---------
<S>                              <C>         <C>         <C>         <C>
Credit Suisse First Boston
  Corporation..................   $           $           $           $
               ................
               ................
Total..........................   $           $           $           $
                                  ======      ======      ======      ======
</TABLE>
 
     The underwriting agreement provides that the underwriters are obligated to
purchase all of the Senior Notes, if any are purchased. The underwriting
agreement provides that if an underwriter defaults the purchase commitments of
non-defaulting underwriters may be increased or the offering of Senior Notes may
be terminated.
 
     The underwriters propose to offer the Senior Notes initially at the public
offering price set forth on the cover page of this prospectus and to selling
group members at that price less a concession of      % of the principal amount
per Senior Note. The underwriters and selling group members may allow a discount
of      % of such principal amount per Senior Note on sales to other
broker/dealers. After the initial public offering, the public offering price and
concession and discount to broker/dealers may be changed by the representatives.
 
     We estimate that our out-of-pocket expenses for this offering will be
approximately $             .
 
     We have agreed to indemnify the underwriters against certain liabilities
under the Securities Act, or to contribute to payments which the underwriters
may be required to make in respect thereof.
 
     The Notes are a new issue of securities with no established trading market.
One or more of the underwriters intends to make a secondary market for the
Senior Notes. However, they are not obligated to do so and may discontinue
making a secondary market for the Senior Notes at any time without notice. No
assurance can be given as to how liquid the trading market for the Senior Notes
will be.
 
     The representatives, on behalf of the underwriters, may engage in
over-allotment, stabilizing transactions syndicate covering transactions and
penalty bids in accordance with Regulation M under the Securities Exchange Act
of 1934, as amended. Over-allotment involves syndicate sales in excess of the
offering size, which creates a syndicate short position. Stabilizing
transactions permit bids to purchase the underlying security so long as the
stabilizing bids do not exceed a specified maximum. Syndicate covering
transactions involve purchases of the Senior Notes in the open market after the
distribution has been completed in order to cover syndicate short positions.
Penalty bids permit the representatives to reclaim a selling concession from a
syndicate member when the Notes originally sold by such syndicate member are
purchased in a syndicate covering transaction
 
                                       63
<PAGE>   146
 
to cover syndicate short positions. Such stabilizing transactions, syndicate
covering transactions and penalty bids may cause the price of the Senior Notes
to be higher than it would otherwise be in the absence of such transactions.
These transactions, if commenced, may be discontinued at any time.
 
     From time to time, certain of the underwriters have provided advisory and
investment banking services to us, for which customary compensation has been
received. It is expected that such underwriters will continue to provide such
services to us in the future.
 
                          NOTICE TO CANADIAN RESIDENTS
 
RESALE RESTRICTIONS
 
     The distribution of the Senior Notes in Canada is being made only on a
private placement basis exempt from the requirement that we prepare and file a
prospectus with the securities regulatory authorities in each province where
trades of the Senior Notes are effected. Accordingly, any resale of Senior Notes
in Canada must be made in accordance with applicable securities laws which will
vary depending on the relevant jurisdiction, and which may require resales to be
made in accordance with available statutory exemptions or pursuant to a
discretionary exemption granted by the applicable Canadian securities regulatory
authority. Purchasers are advised to seek legal advice prior to any resale of
Senior Notes.
 
REPRESENTATION OF PURCHASERS
 
     Each purchaser of the Senior Notes in Canada who receives a purchase
confirmation will be deemed to represent to us and the dealer from whom such
purchase confirmation is received that (1) such purchaser is entitled under
applicable provincial securities laws to purchase such Senior Notes without the
benefit of a prospectus qualified under such securities laws, (2) where required
by law, that such purchaser is purchasing as principal and not as agent, and (3)
such purchaser has reviewed the text above under "Resale Restrictions."
 
RIGHTS OF ACTION (ONTARIO PURCHASERS)
 
     The securities being offered are those of a foreign issuer and Ontario
purchasers will not receive the contractual right of action prescribed by
Section 32 of the Regulation under the Securities Act (Ontario). As a result,
Ontario purchasers must rely on other remedies that may be available, including
common law rights of action for damages or rescission or rights of action under
the civil liability provisions of the U.S. federal securities laws.
 
ENFORCEMENT OF LEGAL RIGHTS
 
     All of the issuer's directors and officers as well as the experts named
herein may be located outside of Canada and, as a result, it may not be possible
for Canadian purchasers to effect service of process within Canada upon the
issuer or such persons. All or a substantial portion of the assets of the issuer
and such persons may be located outside of Canada and, as a result, it may not
be possible to satisfy a judgment against the issuer or
 
                                       64
<PAGE>   147
 
such persons in Canada or to enforce a judgment obtained in Canadian courts
against such issuer or persons outside of Canada.
 
NOTICE TO BRITISH COLUMBIA RESIDENTS
 
     A purchaser of the Senior Notes to whom the Securities Act (British
Columbia) applies is advised that such purchaser is required to file with the
British Columbia Securities Commission a report within ten days of the sale of
any Senior Notes acquired by such purchaser pursuant to this offering. Such
report must be in the form attached to British Columbia Securities Commission
Blanket Order BOR #95/17, a copy of which may be obtained from us. Only one such
report must be filed in respect of Notes acquired on the same date and under the
same prospectus exemption.
 
TAXATION AND ELIGIBILITY FOR INVESTMENT
 
     Canadian purchasers of Senior Notes should consult their own legal and tax
advisors with respect to the tax consequences of an investment in the Senior
Notes in their particular circumstances and with respect to the eligibility of
the Senior Notes for investment by the purchaser under relevant Canadian
legislation.
 
                                 LEGAL MATTERS
 
     The validity of the securities offered hereby will be passed upon for us by
Brobeck, Phleger & Harrison LLP, San Francisco, California. The underwriters
have been represented by Skadden, Arps, Slate, Meagher & Flom LLP, New York, New
York.
 
                                    EXPERTS
 
     The financial statements and schedules incorporated by reference in this
prospectus and elsewhere in the registration statement have been audited by
Arthur Andersen LLP, independent public accountants, as set forth in their
reports. In those reports, that firm states that with respect to a certain
subsidiary its opinion is based on the reports of other public accountants,
namely Moss Adams LLP. The financial statements and supporting schedules
referred to above have been included herein in reliance upon the authority of
that firm as experts in giving said reports.
 
     The consolidated financial statements of Sumas Cogeneration Company, L.P.
and Subsidiary as of December 31, 1998 and 1997 and for each of the years ended
December 31, 1998, 1997 and 1996 included in our Annual Report on Form 10-K
filed with the Securities and Exchange Commission on              , 1999 and
incorporated by reference in this prospectus have been audited by Moss Adams
LLP, independent public accountants, as indicated in their reports with respect
thereto, and are included herein in reliance upon authority of said firm as
experts in giving said reports.
 
                                       65
<PAGE>   148
 
                                    PART II
 
                     INFORMATION NOT REQUIRED IN PROSPECTUS
 
ITEM 14. OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION
 
     The following table sets forth the costs and expenses, other than
underwriting discounts and commissions, payable by Calpine in connection with
the sale of common stock and debt securities being registered. All amounts are
estimates except the SEC registration fee.
 
<TABLE>
<S>                                                           <C>
SEC Registration Fee........................................  $  197,446
NASD Filing Fee.............................................      30,500
Legal Fees and Expenses.....................................           *
Accounting Fees and Expenses................................           *
Printing Fees...............................................           *
Transfer Agent Fees.........................................           *
Miscellaneous...............................................           *
                                                              ----------
          Total.............................................           *
                                                              ==========
</TABLE>
 
- ---------------
* To be supplied by amendment
 
ITEM 15. INDEMNIFICATION OF DIRECTORS AND OFFICERS
 
     Section 145 of the General Corporation Law of the state of Delaware (the
"Delaware Law") empowers a Delaware corporation to indemnify any persons who
are, or are threatened to be made, parties to any threatened, pending or
completed legal action, suit or proceedings, whether civil, criminal,
administrative or investigative (other than action by or in the right of such
corporation), by reason of the fact that such person was an officer or director
of such corporation, or is or was serving at the request of such corporation as
a director, officer, employee or agent of another corporation or enterprise. The
indemnity may include expenses (including attorneys' fees), judgments, fines and
amounts paid in settlement actually and reasonably incurred by such person in
connection with such action, suit or proceeding, provided that such officer or
director acted in good faith and in a manner he reasonably believed to be in or
not opposed to the corporation's best interests, and, for criminal proceedings,
had no reasonable cause to believe his conduct was illegal. A Delaware
corporation may indemnify officers and directors in an action by or in the right
of the corporation under the same conditions, except that no indemnification is
permitted without judicial approval if the officer or director is adjudged to be
liable to the corporation in the performance of his duty. Where an officer or
director is successful on the merits or otherwise in the defense of any action
referred to above, the corporation must indemnify him against the expenses which
such officer or director actually and reasonably incurred.
 
     In accordance with Delaware Law, the certificate of incorporation of the
Company contains a provision to limit the personal liability of the directors of
the Registrant for violations of their fiduciary duty. This provision eliminates
each director's liability to the Registrant or its stockholders for monetary
damages except (i) for any breach of the director's duty of loyalty to the
Registrant or its stockholders, (ii) for acts or omissions not in good faith or
which involve intentional misconduct or a knowing violation of law, (iii) under
Section 174 of the Delaware Law providing for liability of directors for
 
                                      II-1
<PAGE>   149
 
unlawful payment of dividends or unlawful stock purchases or redemptions, or
(iv) for any transaction from which a director derived an improper personal
benefit. The effect of this provision is to eliminate the personal liability of
directors for monetary damages for actions involving a breach of their fiduciary
duty of care, including any such actions involving gross negligence.
 
     Article Ten of the bylaws of the Registrant provides for indemnification of
the officers and directors of the Registrant to the fullest extent permitted by
applicable law.
 
     We have entered into indemnification agreements with our directors and
officers. These agreements provide substantially broader indemnity rights than
those provided under the Delaware Law and the Company's bylaws. The
indemnification agreements are not intended to deny or otherwise limit
third-party or derivative suits against the Company or its directors or
officers, but if a director or officer were entitled to indemnity or
contribution under the indemnification agreement, the financial burden of a
third-party suit would be borne by the Company, and the Company would not
benefit from derivative recoveries against the director or officer. Such
recoveries would accrue to the benefit of the Company but would be offset by the
Company's obligations to the director or officer under the indemnification
agreement.
 
ITEM 16. EXHIBITS
 
<TABLE>
<CAPTION>
  EXHIBIT
    NO.                                  DESCRIPTION
  -------                                -----------
<C>              <S>
    *1.1         Form of Underwriting Agreement (Common Stock)
    *1.2         Form of Underwriting Agreement (Senior Notes)
    +3.1         Amended and restated Certificate of Incorporation of Calpine
                 Corporation, a Delaware corporation(a)
    +3.2         Amended and restated By-laws of Calpine Corporation, a
                 Delaware corporation(a)
    *4.1         Form of Indenture
    +4.2         Indenture dated as of February 17, 1994 between the Company
                 and Shawmut Bank of Connecticut, National Association, as
                 Trustee, including form of Notes.(b)
    +4.3         Indenture dated as of May 16, 1996 between the Company and
                 Fleet National Bank, as Trustee, including form of Notes.(c)
    +4.4         Indenture dated as of July 8, 1997 between the Company and
                 The Bank of New York, as Trustee, including form of
                 Notes.(d)
    +4.5         Indenture dated as of March 31, 1998 between the Company and
                 The Bank of New York, as Trustee, including form of Senior
                 Notes.(e)
    *4.6         Form of Senior Note (included in Exhibit 4.1)
    *5.1         Opinion of Brobeck, Phleger & Harrison LLP
   *12.1         Statement as to Computation of Ratio of Earnings to Fixed
                 Charges
    23.1         Consent of Arthur Andersen LLP, independent accountants
    23.2         Consent of Moss Adams LLP, independent accountants
   *23.3         Consent of Brobeck, Phleger & Harrison LLP (included in
                 Exhibit 5.1).
</TABLE>
 
                                      II-2
<PAGE>   150
 
<TABLE>
<CAPTION>
  EXHIBIT
    NO.                                  DESCRIPTION
  -------                                -----------
<C>              <S>
    24.1         Powers of Attorney (included in the signature page of this
                 Registration Statement).
   *25.1         Statement of Eligibility and Qualification under the Trust
                 Indenture Act of 1939 of Trustee (Form T-1).
</TABLE>
 
- ---------------
 *  To be filed by amendment
 
 +  Previously filed
 
(a) Incorporated by reference to registrant's Registration Statement on Form S-1
    (Registration Statement 33-07497).
 
(b) Incorporated by reference to registrant's Registration Statement on Form S-1
    (Registration Statement No. 33-73160).
 
(c) Incorporated by reference to registrant's Current Report on Form 8-K dated
    August 29, 1996 and filed on September 13, 1996.
 
(d) Incorporated by reference to registrant's Quarterly Report on Form 10-Q
    dated June 30, 1997 and filed on August 14, 1997.
 
(e) Incorporated by reference to registrant's Registration Statement on Form S-4
    (Registration Statement No. 333-61047).
 
ITEM 17. UNDERTAKINGS
 
     The undersigned registrant hereby undertakes:
 
          (1) To file, during any period in which offers or sales are being
     made, a post-effective amendment to this registration statement: (i) to
     include any prospectus required by Section 10(a)(3) of the Securities Act;
     (ii) to reflect in the prospectus any facts or events arising after the
     effective date of the registration statement, or the most recent
     post-effective amendment thereof, which, individually or in the aggregate,
     represent a fundamental change in the information set forth in the
     registration statement; and (iii) to include any material information with
     respect to the plan of distribution not previously disclosed in the
     Registration Statement or any material change to such information in the
     registration statement.
 
          (2) That, for the purpose of determining any liability under the
     Securities Act, each such post-effective amendment shall be deemed to be a
     new registration statement relating to the securities offered therein, and
     the offering of such securities at that time shall be deemed to be the
     initial bona fide offering thereof.
 
          (3) To remove from registration by means of a post-effective amendment
     any of the securities being registered which remain unsold at the
     termination of the offering.
 
     Insofar as indemnification for liabilities arising under the Securities Act
may be permitted to directors, officers and controlling persons of the
registrant pursuant to the foregoing provisions or otherwise, the registrant has
been advised that in the opinion of the SEC such indemnification is against
public policy as expressed in the Securities Act and therefore is unenforceable.
In the event that a claim for indemnification against such liabilities, other
than the payment by the registrant of expenses incurred or paid by a
 
                                      II-3
<PAGE>   151
 
director, officer or controlling person of the registrant in the successful
defense of any action, suit or proceeding is asserted by such director, officer
or controlling person in connection with the securities being registered, the
registrant will, unless in the opinion of its counsel the matter has been
settled by controlling precedent, submit to a court of appropriate jurisdiction
the question whether such indemnification by it is against public policy as
expressed in the Securities Act and will be governed by the final adjudication
of such issue.
 
     The undersigned registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act, each filing of the
registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
Exchange Act, and, where applicable, each filing of an employee benefit plan's
annual report pursuant to Section 15(d) of the Exchange Act, that is
incorporated by reference in the registration statement shall be deemed to be a
new registration statement relating to the securities offered therein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.
 
                                      II-4
<PAGE>   152
 
                                   SIGNATURES
 
     Pursuant to the requirements of the Securities Act of 1933 the registrant
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-3 and has duly caused this registration
statement to be signed on its behalf by the undersigned, thereunto duly
authorized in the City of San Jose, State of California, on this 17th day of
February, 1999.
 
                                          CALPINE CORPORATION
 
                                          By /s/ PETER CARTWRIGHT
                                            ------------------------------------
                                             Peter Cartwright
                                             Chairman, President and Chief
                                             Executive Officer
 
     KNOW ALL MEN BY THESE PRESENTS, that each person whose signature appears
below constitutes and appoints Peter Cartwright and Ann B. Curtis, and each of
them, as his true and lawful attorneys-in-fact and agents, with full power of
substitution and resubstitution, for him and in his name, place and stead, in
any and all capacities, to sign any and all amendments (including post-effective
amendments) to this registration statement, and to file same, with all exhibits
thereto, and other documents in connection therewith, with the Securities and
Exchange Commission, granting unto said attorneys-in-fact and agents, and each
of them, full power and authority to do and perform each and every act and thing
requisite and necessary to be done in connection therewith, as fully to all
intents and purposes as he might or could do in person, hereby ratifying and
confirming all that said attorneys-in-fact and agents, and any of them, or their
or his substitutes, may lawfully do or cause to be done by virtue thereof.
 
     Pursuant to the requirements of the Securities Act of 1933, as amended,
this registration statement has been signed below by the following persons on
behalf of Calpine and in the capacities and on the dates indicated:
 
<TABLE>
<CAPTION>
                  SIGNATURE                                TITLE                     DATE
                  ---------                                -----                     ----
<S>                                              <C>                           <C>
            /s/ PETER CARTWRIGHT                    Chairman, President,       February 17, 1999
- ---------------------------------------------     Chief Executive Officer,
              Peter Cartwright                          and Director
                                                    (Principal Executive
                                                          Officer)
 
              /s/ ANN B. CURTIS                   Executive Vice President     February 17, 1999
- ---------------------------------------------           and Director
                Ann B. Curtis                     (Principal Financial and
                                                    Accounting Officer)
 
            /s/ JEFFREY E. GARTEN                         Director             February 17, 1999
- ---------------------------------------------
              Jeffrey E. Garten
 
             /s/ SUSAN C. SCHWAB                          Director             February 17, 1999
- ---------------------------------------------
               Susan C. Schwab
</TABLE>
 
                                      II-5
<PAGE>   153
 
<TABLE>
<CAPTION>
                  SIGNATURE                                TITLE                     DATE
                  ---------                                -----                     ----
<S>                                              <C>                           <C>
           /s/ GEORGE J. STATHAKIS                        Director             February 17, 1999
- ---------------------------------------------
             George J. Stathakis
 
             /s/ JOHN O. WILSON                           Director             February 17, 1999
- ---------------------------------------------
               John O. Wilson
 
            /s/ V. ORVILLE WRIGHT                         Director             February 17, 1999
- ---------------------------------------------
              V. Orville Wright
</TABLE>
 
                                      II-6
<PAGE>   154
 
                               INDEX TO EXHIBITS
 
<TABLE>
<CAPTION>
  EXHIBIT
    NO.                             DESCRIPTION
  -------                           -----------
  <C>       <S>                                                           <C>
    *1.1    Form of Underwriting Agreement (Common Stock)
    *1.2    Form of Underwriting Agreement (Senior Notes)
    +3.1    Amended and restated Certificate of Incorporation of Calpine
            Corporation, a Delaware corporation(a)
    +3.2    Amended and restated By-laws of Calpine Corporation, a
            Delaware corporation(a)
    *4.1    Form of Indenture
    +4.2    Indenture dated as of February 17, 1994 between the Company
            and Shawmut Bank of Connecticut, National Association, as
            Trustee, including form of Notes.(b)
    +4.3    Indenture dated as of May 16, 1996 between the Company and
            Fleet National Bank, as Trustee, including form of Notes.(c)
    +4.4    Indenture dated as of July 8, 1997 between the Company and
            The Bank of New York, as Trustee, including form of
            Notes.(d)
    +4.5    Indenture dated as of March 31, 1998 between the Company and
            The Bank of New York, as Trustee, including form of Senior
            Notes.(e)
    *4.6    Form of Senior Note (included in Exhibit 4.1)
    *5.1    Opinion of Brobeck, Phleger & Harrison LLP
   *12.1    Statement as to Computation of Ratio of Earnings to Fixed
            Charges
    23.1    Consent of Arthur Andersen LLP, independent accountants
    23.2    Consent of Moss Adams LLP, independent accountants
   *23.3    Consent of Brobeck, Phleger & Harrison LLP (included in
            Exhibit 5.1).
    24.1    Powers of Attorney (included in the signature page of this
            Registration Statement).
   *25.1    Statement of Eligibility and Qualification under the Trust
            Indenture Act of 1939 of Trustee (Form T-1).
</TABLE>
 
- ---------------
 *  To be filed by amendment
 
 +  Previously filed
 
(a) Incorporated by reference to registrant's Registration Statement on Form S-1
    (Registration Statement 33-07497).
 
(b) Incorporated by reference to registrant's Registration Statement on Form S-1
    (Registration Statement No. 33-73160).
 
(c) Incorporated by reference to registrant's Current Report on Form 8-K dated
    August 29, 1996 and filed on September 13, 1996.
 
(d) Incorporated by reference to registrant's Quarterly Report on Form 10-Q
    dated June 30, 1997 and filed on August 14, 1997.
 
(e) Incorporated by reference to registrant's Registration Statement on Form S-4
    (Registration Statement No. 333-61047).

<PAGE>   1
 
                                                                    EXHIBIT 23.1
 
                       CONSENT OF INDEPENDENT ACCOUNTANTS
 
     As independent public accountants, we hereby consent to the incorporation
by reference in this registration statement of our reports dated February 5,
1999 in Calpine Corporation's Form 10-K for the year ended December 31, 1998 and
to all references to our Firm included in this registration statement.
 
                                          ARTHUR ANDERSEN LLP
 
February 18, 1999

<PAGE>   1
 
                                                                    EXHIBIT 23.2
 
                   CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS
 
     We consent to the incorporation by reference in this Registration Statement
on Form S-3 of Calpine Corporation for the registration of           shares of
its common stock and   % Senior Notes due 2004,   % Senior Notes due 2006,   %
Senior Notes due 2009 and   % Senior Notes due 2011, of our report of Sumas
Cogeneration Company, L.P. and Subsidiary dated January 20, 1999, on our audits
of the consolidated financial statements of Sumas Cogeneration Company, L.P. and
Subsidiary as of December 31, 1998 and 1997, and for each of the three years
ended December 31, 1998, which report is included in Calpine Corporation's 1998
Annual Report on Form 10-K, filed with the Securities and Exchange Commission.
We also consent to the reference to our firm under the caption "Experts."
 
                                          MOSS ADAMS LLP
 
Everett, Washington
February 18, 1999


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