<TABLE> <S> <C>
<PAGE>
<ARTICLE> UT
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE
CONSOLIDATED BALANCE SHEET AND STATEMENT OF INCOME FROM ACE'S 3RD QUARTER
2000-10-2.
</LEGEND>
<MULTIPLIER> 1,000
<S> <C>
<PERIOD-TYPE> 9-MOS
<FISCAL-YEAR-END> DEC-31-2000
<PERIOD-START> JAN-01-2000
<PERIOD-END> SEP-30-2000
<BOOK-VALUE> PER-BOOK
<TOTAL-NET-UTILITY-PLANT> 889,582
<OTHER-PROPERTY-AND-INVEST> 115,606
<TOTAL-CURRENT-ASSETS> 296,414
<TOTAL-DEFERRED-CHARGES> 1,099,516
<OTHER-ASSETS> 73,920
<TOTAL-ASSETS> 2,475,038
<COMMON> 54,963
<CAPITAL-SURPLUS-PAID-IN> 410,194
<RETAINED-EARNINGS> 121,730
<TOTAL-COMMON-STOCKHOLDERS-EQ> 586,887
118,950
6,231
<LONG-TERM-DEBT-NET> 914,827
<SHORT-TERM-NOTES> 0
<LONG-TERM-NOTES-PAYABLE> 0
<COMMERCIAL-PAPER-OBLIGATIONS> 0
<LONG-TERM-DEBT-CURRENT-PORT> 40,075
0
<CAPITAL-LEASE-OBLIGATIONS> 15,200
<LEASES-CURRENT> 15,480
<OTHER-ITEMS-CAPITAL-AND-LIAB> 777,388
<TOT-CAPITALIZATION-AND-LIAB> 2,475,038
<GROSS-OPERATING-REVENUE> 728,101
<INCOME-TAX-EXPENSE> 24,121
<OTHER-OPERATING-EXPENSES> 602,887
<TOTAL-OPERATING-EXPENSES> 627,008
<OPERATING-INCOME-LOSS> 101,093
<OTHER-INCOME-NET> 5,438
<INCOME-BEFORE-INTEREST-EXPEN> 106,531
<TOTAL-INTEREST-EXPENSE> 62,690
<NET-INCOME> 43,841
1,599
<EARNINGS-AVAILABLE-FOR-COMM> 42,242
<COMMON-STOCK-DIVIDENDS> 50,482
<TOTAL-INTEREST-ON-BONDS> 0
<CASH-FLOW-OPERATIONS> 185,055
<EPS-BASIC> 0
<EPS-DILUTED> 0
</TABLE>
