SEC FORM 3

SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person^*

MacMahon Douglas M

(Last)

(First)

(Middle)

C/O FARALLON CAPITAL MANAGEMENT, L.L.C.,

ONE MARITIME PLAZA, SUITE 1325

(Street)

SAN FRANCISCO

94111

(City)

(State)

(Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
01/01/2007

3. Issuer Name and Ticker or Trading Symbol
CATALYTICA ENERGY SYSTEMS INC [ CESI ]

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

Director	X	10% Owner
Officer (give title below)	X	Other (specify below)
		Member of Group Owning 10%

5. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock, par value $0.001	2,274,960	I	See footnotes⁽¹⁾⁽²⁾⁽³⁾⁽⁴⁾⁽⁵⁾⁽⁶⁾

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
1. Title of Derivative Security (Instr. 4)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)

Explanation of Responses:

1. The amount of securities shown in this row is owned directly by Farallon Capital Partners, L.P., Farallon Capital Institutional Partners, L.P., Farallon Capital Institutional Partners II, L.P., Farallon Capital Institutional Partners III, L.P. and Tinicum Partners, L.P. (collectively, the "Partnerships") and by a discretionary account (the "Managed Account") managed by Farallon Capital Management, L.L.C. ("FCMLLC"). As the general partner to each of the Partnerships, Farallon Partners, L.L.C. ("FPLLC") may be deemed to be the beneficial owner of the Issuer's securities held by each of the Partnerships. FCMLLC, as the registered investment advisor to the Managed Account, may be deemed to be the beneficial owner of the Issuer's securities held by the Managed Account.

2. Each of Noonday G.P. (U.S.), L.L.C. ("NGPUS") and Noonday Asset Management, L.P. ("NAMLP"), as a sub-investment adviser to the Partnerships and the Managed Account, may be deemed to be the beneficial owner of the Issuer's securities held by the Partnerships and the Managed Account. As the general partner of NAMLP, Noonday Capital, L.L.C. ("NCLLC") may be deemed to be the beneficial owner of the Issuer's securities held by the Partnerships and the Managed Account.

3. Effective as of January 1, 2007, Douglas M. MacMahon ("MacMahon") became a managing member of FPLLC and FCMLLC, and as a result MacMahon may be deemed to be the beneficial owner of the Issuer's securities held by the Partnerships and the Managed Account.

4. All of such securities of the Issuer have been previously reported by the Partnerships, FCMLLC on behalf of the Managed Account and other related entities and individuals on the Form 4s filed on July 8, 2004 by the Partnerships, FCMLLC on behalf of the Managed Account and the other entities and individuals listed on such forms. NGPUS, NAMLP, NCLLC and David I. Cohen also filed a Form 3 with respect to such securities on January 4, 2005. Saurabh K. Mittal also filed a Form 3 with respect to such securities on October 11, 2005. Jason E. Moment also filed a Form 3 with respect to such securities on January 10, 2006. There have been no transactions in such securities by any such entities or individuals since such forms were filed.

5. MacMahon, FCMLLC, NGPUS, NAMLP, NCLLC and the individuals identified on the prior Form 3s and 4s disclaim any beneficial ownership of any of the Issuer's securities reported or referred to herein for purposes of Rules 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "34 Act"). FPLLC disclaims any beneficial ownership of any of the Issuer's securities reported or referred to herein for purposes of Rule 16a-1(a) under the '34 Act, or otherwise, except as to securities representing FPLLC's pro rata interest in, and interest in the profits of, the Partnerships.

6. MacMahon, together with the entities and individuals identified in footnotes (1), (2) and (4) of this Form 3, may be deemed members of a group holding equity securities of the Issuer. The filing of this Form 3 shall not be deemed to be an admission that such entities and individuals are member of such group.

	/s/ Mark C. Wehrly, as attorney-in-fact and/or authorized signer for Douglas M. MacMahon	01/08/2007
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 5 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
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