X0202 4 2007-10-01 1 0001053361 CATALYTICA ENERGY SYSTEMS INC CESI 0001044321 MARXE AUSTIN W & GREENHOUSE DAVID M C/O SPECIAL SITUATIONS FUNDS 527 MADISON AVENUE, SUITE 2600 NEW YORK NY 10022 0 0 1 0 Common Stock 2007-10-01 4 J 0 3746656 1.8955 D 0 I By Limited Partnerships On October 1st Catalytica Energy Systems had a mandatory exchange to Renegy Holdings, Inc. We do not own 10% of Renegy Holdings, Inc. This is a joint filing by Austin W. Marxe (Marxe) and David M. Greenhouse (Greenhouse). They share voting and investment control over all securities owned by Special Situations Fund III QP, LP (SSFQP) and Special Situations Cayman Fund, L.P. (CAY), respectively. 0 shares of Common Stock are owned by SSFQP and 0 shares of Common Stock are owned by CAY. The interest of Marxe and Greenhouse in the shares of Common Stock owned by SSFQP and CAY is limited to the extent of his pecuniary interest. Austin W. Marxe 2007-10-04 David M. Greenhouse 2007-10-04