<PAGE>
                                                                   Exhibit 10.25

                       FIRST AMENDMENT TO CREDIT AGREEMENT

          This FIRST AMENDMENT TO CREDIT AGREEMENT (this "Amendment"), dated as
of June 27, 2007, amends the Credit Agreement (as further amended from time to
time, the "Credit Agreement"), dated as of September 1, 2006, among SNOWFLAKE
WHITE MOUNTAIN POWER, LLC ("SWMP"), RENEGY, LLC ("Renegy"), RENEGY TRUCKING, LLC
("Renegy Trucking" and together with Renegy and SWMP, the "Borrowers"), the
financial institutions from time to time party thereto (collectively, the
"Lenders") and COBANK, ACB, as administrative agent for the Lenders (in such
capacity, the "Administrative Agent"), as letter of credit issuer, collateral
agent and as a Lender. Terms used herein but not defined shall have the meaning
given to them in the Credit Agreement and section references refer to sections
of the Credit Agreement unless otherwise stated.

     WHEREAS, the Borrowers have agreed to certain signed change orders,
unsigned change orders and estimated future change orders with various
construction contractors totaling $4,089,536 (the "Change Orders"), the details
of which have been previously provided by Borrowers to Administrative Agent.

     WHEREAS, pursuant to that certain Asset Purchase Agreement between
Ponderosa Transport, Inc., an Arizona corporation ("PTI") and Renegy Trucking,
dated as of January 1, 2007, whereby Renegy Trucking acquired certain assets of
PTI, Renegy Trucking has executed a related promissory note, a copy of which is
attached hereto as Exhibit A (the "PTI Note"), and is negotiating the purchase
of associated real property (the "PTI Purchase").

     WHEREAS, the Borrowers were unable to provide the audited financial
statements for the fiscal year ending December 31, 2006 on or prior to April 30,
2007 but will be able to deliver such financial statements on or prior to July
31, 2007.

     WHEREAS, the Borrowers have proposed that Renegy enter into a grinder
co-ownership agreement with William Johnson ("Johnson"), pursuant to which
Renegy and Johnson contemplate forming a joint venture (the "Johnson
Agreement"), a draft of which is attached hereto as Exhibit B.

     WHEREAS, Renegy has entered into that certain purchase agreement with Les
Machineries Verville (brand name of Premier Tech Technologies Limited) ("Les
Machineries"), dated as of April 18, 2007 (the "Les Machineries Agreement"), a
copy of which is attached hereto as Exhibit C.

     WHEREAS, Renegy and Jackson Lumber Harvester Company, Incorporated
("Jackson") have entered into that certain Sales Contract dated as of April 19,
2007, relating to two used shaving mills and associated parts, and that certain
Sales Contract dated as of April 19, 2007, relating to three new shaving mills
and associated parts (collectively, the "Jackson Contracts"), copies of which
are attached hereto as Exhibit D.

     WHEREAS, Renegy has entered into that certain Master Lease Agreement dated
as of May 18, 2007 with Chase Equipment Leasing, Inc. (the "Chase Capital
Lease"), in order to finance the purchases under the Les Machineries Agreement
and the Jackson Contracts, a copy of which is attached hereto as Exhibit E.

<PAGE>

     WHEREAS, the Borrowers have terminated that certain Trade Contract No.
109/03.3131 Concrete dated August 3, 2006 by and between SWMP and D.W. Lusk
Contracting Co. (the "Lusk Contract") and that certain trade Contract No.
109/02.4340 Turbine/Generator/Condenser dated July 6, 2006 and that certain
Purchase Order No. 109/02.4342 Generator Testing dated July 15, 2006 by and
between SWMP and Tetrad Service, Inc. (collectively, the "Tetrad Contract").

     WHEREAS, the Borrowers have requested that Administrative Agent and the
undersigned Lender(s) waive certain defaults as set forth herein.

     WHEREAS, the Borrowers have requested that Administrative Agent and the
undersigned Lender(s) consent to certain matters as set forth herein.

     WHEREAS, the Borrowers have requested that the Majority Lenders agree to
amend the Credit Agreement in certain other respects as set forth herein.

     NOW THEREFORE, in consideration of the premises, and for other good and
valuable consideration, the receipt and adequacy of which are hereby
acknowledged, the parties hereto agree as follows:

1.   Waivers. The Administrative Agent and undersigned Lender(s) hereby:

     (a)  waive any default arising from Renegy's failure to comply with
          Sections 5.4.6, 6.5, 6.7 and 6.10 or any other provision of the Credit
          Agreement by entering into the Johnson Agreement;

     (b)  waive any default arising from Renegy's failure to comply with
          Sections 6.2, 6.3 and 6.12 or any other provision of the Credit
          Agreement by entering into the Les Machineries Agreement;

     (c)  waive any default arising from Renegy's failure to comply with
          Sections 5.4.6, 6.2, 6.3 and 6.12 or any other provision of the Credit
          Agreement by entering into the Jackson Contracts;

     (d)  waive any default arising from Renegy's failure to comply with
          Sections 5.4.6, 6.2, 6.3 and 6.12, or any other provision of the
          Credit Agreement by entering into the Chase Capital Lease;

     (e)  waive any default arising from Renegy Trucking's failure to comply
          with Sections 6.3 or any other provision of the Credit Agreement by
          entering into the PTI Note and Sections 5.4.6, 6.12 and 6.21 by
          entering into the PTI Purchase;

     (f)  waive any default arising from Borrowers' failure to comply with
          Section 5.5.1(a) and the Consent and Waiver Agreement, dated as of
          December 22, 2006, between the Borrowers and the Administrative Agent
          by delivering audited financial statements for the fiscal year ending
          December 31, 2006 on or prior to April 30, 2007;

     (g)  waive any default arising from the Borrowers failure to comply with
          Sections 5.4.9 and 6.12 or any other provision of the Credit Agreement
          by agreeing to the Change Orders;

<PAGE>

     (h)  waive any default arising from SWMP's failure to comply with Sections
          6.12.2 and 8.1.15(d) or any other provision of the Credit Agreement by
          SWMP's termination of the Lusk Contract and the Tetrad Contract.

2.   Consents. The Administrative Agent, in consultation with the Independent
     Engineer and at the direction of the Majority Lenders, hereby:

     (a)  consents to and approves of the Change Orders, as required under
          Section 6.12.2(a) or any other provision of the Credit Agreement;

     (b)  consents to the Les Machineries Agreement as required under Section
          6.12.2(a) or any other provision of the Credit Agreement;

     (c)  consents to the Jackson Contracts as required under Section 6.12.2(a)
          or any other provision of the Credit Agreement;

     (d)  consents to the Chase Capital Lease as required under Section
          6.12.2(a) or any other provision of the Credit Agreement;

     (e)  consents to the Johnson Agreement and the ongoing relationship between
          Renegy and Johnson contemplated thereunder;

     (f)  consents to the PTI Note and the PTI Purchase and the ongoing
          relationship between Renegy Trucking and PTI contemplated thereunder
          as required under Section 6.12.2(a); and

     (g)  consents to the termination of the Lusk Contract and the Tetrad
          Contract as required under Section 6.12.2(f) or any other provision of
          the Credit Agreement.

3.   Amendments. The Credit Agreement is hereby amended as follows:

     (a)  The last sentence of Section 2.2.1 is hereby deleted in its entirety
          and replaced with the following:

               In their sole discretion, LC Issuer and all of the Lenders may
               agree to extend the LC Facility Expiration Date (and the Letter
               of Credit) for an additional two year period from the most recent
               calendar anniversary of the Closing Date upon request of SWMP
               delivered to Administrative Agent annually on or prior to
               December 15th of each calendar year.

     (b)  Section 2.2.3(e)(i) is hereby deleted in its entirety and replaced
          with the following:

               (i) 366 days after the related Drawing Date,

4.   Conditions.

     (a)  The waiver of Paragraph 1(a) above is conditioned upon the timely
          delivery to the Administrative Agent of the executed Johnson Agreement
          and any related ancillary documents as reasonably satisfactory to and
          deemed necessary by the Administrative Agent.

<PAGE>

     (b)  The waiver of Paragraph 1(b) above is conditioned upon the timely
          delivery to the Administrative Agent of the Les Machineries Agreement
          and any related ancillary documents as reasonably satisfactory to and
          deemed necessary by the Administrative Agent.

     (c)  The waiver of Paragraph 1(c) above is conditioned upon the timely
          delivery to the Administrative Agent of the executed Jackson Contracts
          and any related ancillary documents as reasonably satisfactory to and
          deemed necessary by the Administrative Agent.

     (d)  The waiver of Paragraph 1(d) above is conditioned upon the timely
          delivery to the Administrative Agent of the PTI Note and any documents
          related to the PTI Purchase as reasonably satisfactory to and deemed
          necessary by the Administrative Agent.

     (e)  The waiver of Paragraph 1(f) above is conditioned upon the
          Administrative Agent's receipt of the Borrowers' audited financial
          statements for the fiscal year ending December 31, 2006 on or prior to
          July 31, 2007.

5.   Representations and Warranties. The Borrowers represent and warrant to the
     Administrative Agent and the undersigned Lender(s) as follows:

     (a)  The representations and warranties made by the Borrowers in Article 4
          of the Credit Agreement and each other Credit Document are true and
          correct in all material respects on and as of the date hereof, except
          to the extent such representations and warranties expressly relate to
          an earlier date.

     (b)  Other than as addressed herein, no Default or Event of Default has
          occurred and is continuing.

     (c)  No Material Adverse Effect has occurred and is continuing.

6.   Effect of Amendment. On and after the date of this Amendment, each
     reference in the Credit Documents to the Credit Agreement shall mean the
     Credit Agreement as amended hereby and as heretofore amended. Except as
     specifically amended above, the Credit Agreement shall remain in full force
     and effect and is hereby ratified and confirmed. The execution, delivery
     and effectiveness of this Amendment shall not, except as expressly provided
     herein, operate as a waiver of any right, power or remedy of the
     Administrative Agent.

7.   Headings. The headings in this Amendment are for convenience of reference
     only and are not part of the substance hereof.

8.   Governing Law. This Amendment shall be governed by and construed in
     accordance with the laws of the State of New York, without reference to
     rules of conflicts of laws (other than Section 5-1401 of the New York
     General Obligations Law).

9.   Enforceability. Should any one or more of the provisions of this Agreement
     be determined to be illegal or unenforceable as to one or more of the
     parties hereto, all other provisions nevertheless shall remain effective
     and binding on the parties hereto.

10.  Counterparts. This Amendment may be executed in multiple originals and by
     counterpart.

<PAGE>

                            [Signature Page Follows]

<PAGE>

     IN WITNESS HEREOF, the parties have caused this First Amendment to Credit
Agreement to be duly executed by their officers duly authorized as of the date
first above written.

                                        SNOWFLAKE WHITE MOUNTAIN POWER, LLC,
                                        as Borrower


                                        By: /s/ Robert M. Worsley
                                            ------------------------------------
                                        Name: Robert M. Worsley
                                        Title: Manager


                                        RENEGY, LLC,
                                        as Borrower


                                        By: /s/ Robert M. Worsley
                                            ------------------------------------
                                        Name: Robert M. Worsley
                                        Title: Manager


                                        RENEGY TRUCKING, LLC,
                                        as Borrower


                                        By: /s/ Robert M. Worsley
                                            ------------------------------------
                                        Name: Robert M. Worsley
                                        Title: Manager


                                        COBANK, ACB,
                                        as Administrative Agent and a Lender


                                        By: /s/ David B. Willis
                                            ------------------------------------
                                        Name: David B. Willis
                                        Title: Managing Director, Project and
                                               Structured Finance,
                                               Communications and Energy Banking
                                               Group