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Exhibit 23.1
CONSENT OF INDEPENDENT AUDITORS
We consent to the reference to our firm under the captions "Experts" and
"Selected Financial Data" and to the use of our report dated August 25, 2000
in Amendment No. 4, to the Registration Statement (Form S-1 No. 333-44772) and
related Prospectus for Catalytica Energy Systems, Inc. (formerly Catalytica
Combustion Systems, Inc.) and Catalytica Advanced Technologies, Inc. (a
combined company in the development stage) for the registration of its common
stock.
/s/ Ernst & Young LLP
San Jose, California
November 13, 2000
