Exhibit
10.20




WAIVER
AGREEMENT







WAIVER
AGREEMENT (“Waiver
Agreement”) dated as of February 25, 2009 among GSC ACQUISITION COMPANY,
a Delaware corporation (“GSCAC”), GSCAC Holdings I LLC,
a Delaware limited liability company (“Holdco Sub”), GSCAC Holdings
II LLC, a Delaware limited liability company (“Holdco Sub2”), GSCAC Merger
Sub LLC, a Delaware limited liability company (“Merger Sub” and together with
GSCAC, Holdco Sub and Holdco Sub2, the “GSCAC Parties”), and COMPLETE
ENERGY HOLDINGS, LLC, a Delaware limited liability company (“CEH”).




WHEREAS,
the parties hereto are parties to an Agreement and Plan of Merger dated as of
May 9, 2008 (the “Merger
Agreement”); any capitalized term not defined in this Waiver Agreement
shall have the meaning given such term in the Merger Agreement.




WHEREAS,
Section 6.13 of the Merger Agreement limits the ability of the parties thereto
and other person from engaging in discussions or taking certain other actions
concerning any proposal for a merger, sale or purchase of substantial assets,
sale or purchase of shares of capital stock or other securities,
recapitalization or other business combination transaction involving a GSCAC
Party or any Project Companies on the one hand and any third party on the other
hand; and




WHEREAS,
GSCAC and CEH each desires to waive certain provisions of Section 6.13 of the
Merger Agreement to the extent provided herein.




NOW,
THEREFORE, in consideration of the foregoing recitals and other good and
valuable consideration, the receipt and sufficiency of which is hereby
acknowledged, the parties hereto agree as follows:




1.  The GSCAC
Parties and CEH each hereby waives the limitations contained in Section 6.13(a)
of the Merger Agreement to the extent necessary to permit the GSCAC Parties and
CEH, and their respective Affiliates and Representatives, to directly or
indirectly solicit and initiate discussions and/or negotiations with, enter into
confidentiality agreements on customary terms with and furnish any information
about themselves and their respective Affiliates to, and otherwise assist,
facilitate or encourage, any Person or group concerning any proposal for a
merger, sale or purchase of substantial assets, sale or purchase of shares of
capital stock or other securities, recapitalization or other business
combination transaction involving any GSCAC Parties or any Project Companies on
the one hand and any third party on the other hand (any such potential
transaction, an “Alternative
Proposal”).  Notwithstanding the foregoing, (i) CEH agrees that
it shall not, and shall not permit any other Project Company or any of its
Affiliates or Representatives to, enter into any Contract or otherwise make any
commitments in connection with any Alternative Proposal (other than a
confidentiality agreement on customary terms), except with the consent of GSCAC;
and (ii) GSCAC agrees that it shall not, and shall not permit any GSCAC Party or
any of its Affiliates or Representatives to, enter into any Contract or
otherwise make any commitments in









connection
with any Alternative Proposal (other than a confidentiality agreement on
customary terms), except with the consent of CEH.




2.  In
addition, GSCAC and CEH each hereby waives the requirements contained in the
second and third sentences of Section 6.13(a) of the Merger Agreement with
respect to any discussions, negotiations or other matters permitted from and
after the date hereof by Section 1 above.




3.  CEH
acknowledges that GSCAC shall disclose this Agreement in a filing with the SEC,
and CEH hereby consents to such disclosure to the extent required by Section
6.11 of the Merger Agreement.




4.  Except as
expressly set forth herein, the waivers and consent contained in this Waiver
Agreement shall not constitute an amendment or waiver of any term of condition
of the Merger Agreement or any other Transaction Document, and all such terms
and conditions shall remain in full force and effect and are hereby ratified and
confirmed in all respects.




5.  This
Waiver Agreement shall be governed by and construed in accordance with the laws
of the State of New York, without giving effect to any conflict or choice of law
provision that would result in the imposition of another state’s
Law.




6.  The
headings and captions contained herein are for convenience and shall not control
or affect the meaning or construction of any provision hereof.




7.  This
Waiver Agreement may be executed in counterparts, each of which shall be deemed
to be an original and which together shall constitute one and the same
instrument




8.  This
Waiver Agreement shall become effective as of the date hereof when both (i) each
party hereto shall have executed a counterpart hereof and (ii) each party to the
TCW Consent shall have executed a consent to this Waiver Agreement.




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IN
WITNESS WHEREOF, the parties hereto have caused this Waiver Agreement to be duly
executed by their respective authorized officers as of the day and year first
above written.






GSC
      ACQUISITION COMPANYBy:
            /s/
      Peter R. FrankName:
            Peter R. FrankTitle:
            Chief
      Executive Officer and Principal
      Accounting andFinancial
      Officer








GSCAC
      HOLDINGS I LLCBy:
            GSC
      ACQUISITION COMPANY, as its sole memberBy:
            /s/ Peter R. FrankName:
            Peter R. FrankTitle:
            Chief Executive Officer and Principal Accounting
      andFinancial
      Officer








GSCAC
      HOLDINGS II LLCBy:
            GSCAC
      HOLDINGS I LLC, as its sole memberBy:
            GSC
      ACQUISITION COMPANY, as its sole memberBy:
            /s/ Peter R. FrankName:
            Peter R. FrankTitle:
            Chief
      Executive Officer and Principal Accounting
      andFinancial
      Officer





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GSCAC
      MERGER SUB LLCBy:
            GSCAC
      HOLDINGS II LLC, as its sole memberBy:
            GSCAC
      HOLDINGS I LLC, as its sole memberBy:
            GSC
      ACQUISITION COMPANY, as its sole memberBy:
            /s/
      Peter R. FrankName:
            Peter R. FrankTitle:
            Chief
      Executive Officer and Principal Accounting
      andFinancial
      Officer








COMPLETE
      ENERGY HOLDINGS,LLCBy:
            /s/ Hugh A.
      TarpleyName:
            Hugh A. TarpleyTitle:
            Managing
      Director







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