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                                                                   Exhibit 10.26

CONFIDENTIAL TREATMENT REQUESTED: Certain portions of this document have been
omitted pursuant to a request for confidential treatment and, where applicable,
have been marked with an asterisk ("[****]") to denote where omissions have been
made. The confidential material has been filed separately with the Securities
and Exchange Commission.

                                        NUMBER 267 OF THE ROLE OF DEEDS FOR 2006

                 AMENDMENT TO THE MASTER JOINT VENTURE AGREEMENT

Q-Cells AG, Guardianstrasse 16, 06766 Thalheim, registered with the commercial
register of the local court of Stendal under HRB 16621 (hereinafter also
"Q-CELLS"), Evergreen Solar, Inc. with registered office at 138 Bartlett Street,
Marlboro, Massachusetts 01752, USA, a company duly organised and existing under
the laws of the state of Delaware, USA, (hereinafter also "EVERGREEN SOLAR,
INC."), Renewable Energy Corporation ASA, with registered office in Veritasveien
14, 1323 Hovik, Norway, a company duly organised and existing under the laws of
Norway (hereinafter also "REC"),REC Solar Grade Silicon LLC, with registered
office at 3322 Road "N" N.E. Moses Lake, WA 98837 USA, (hereinafter also "REC
SOLAR GRADE SILICON") and EverQ GmbH, Sonnenallee 14 -18, 06766 Thalheim,
registered with the commercial register of the local court of Stendal under HRB
4769 (hereinafter also "EVERQ") agree that REC has fulfilled its obligations
under Section 3.4 of the Master Joint Venture Agreement contained in the
reference deed 287/2005 (the "MASTER JOINT VENTURE AGREEMENT").

By increasing their respective ownership in EverQ to 33.33% each, Q-Cells and
REC are exercising the options granted to them under Section 3.5 (c) and 3.5 (d)
of the Master Joint Venture Agreement, respectively.

Against that backdrop, the Master Joint Venture Agreement is hereby amended as
follows (Sections and Articles refer to the corresponding Section / Article in
the Master Joint Venture Agreement):

1.   In Section 1.2, the following definitions are cancelled:

     "Fair Market Price"

     "Grant Impunity Notice"

     "Q Preferential Offer"

     [****]

     "REC Option"

     "REC Option Exercise Letter"

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                                       -2-


     "REC Offer Date"

     [****]

2.   In Section 1.2, the following definition is reworded as follows:

     "SECOND REC SUPPLY AGREEMENT" shall mean the supply agreement between REC
     Solar Grade Silicon LLC and EverQ dated September 29, 2006.

3.   Section 2.2 is hereby cancelled.

4.   Section 3.4 is hereby cancelled. The numbers of the remaining sections of
     Article III. shall remain unaffected.

5.   Section 3.5 shall be reworded as follows:

          "3.5. Further Capacity Expansions and Additional Financing.

               (a) It is the intent of the Parties that EverQ shall have an
     initial capacity to manufacture 30 MW per year (the "INITIAL CAPACITY").
     The Parties shall use reasonable best efforts to cause EverQ to achieve the
     Initial Capacity as soon as practicable. It is also the intent of the
     Parties that EverQ shall, if economically viable, expand its manufacturing
     capacity to approximately 300 MW (the "CAPACITY EXPANSION"). Without
     limiting the foregoing, each of the Parties shall, and shall cause EverQ to
     approve the Capacity Expansion, if economically viable, and commence
     substantial activities in furtherance of the Capacity Expansion following
     September 29, 2006. To that date, approximately [****] of the Capacity
     Expansion has been approved by the Parties and commenced.

               (b) A majority of the Supervisory Board which includes at least
     one Director designated by each of not less than two of the Parties to this
     Agreement shall have the ability to approve a Capacity Expansion following
     a determination by such majority of the Supervisory Board that the Capacity
     Expansion is in the best interest of EverQ.

               (c) Compensation for Grant Repayment Obligations. If EverQ is
     required to repay all or part of the Government Investment Grant, the
     following will occur:

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                                       -3-


                    (i) E, Q and REC will loan EverQ the amount to be repaid and
     EverQ will repay the part of the Government Investment Grant to the
     appropriate government authorities.

                    (ii) The loan will be at [****]

                    (iii) The loan will be made by the Parties in proportion to
     the shareholdings in EverQ and will be adjusted accordingly as such
     shareholdings change.

               (d) EverQ Debt. E and Q have provided guarantees to the EverQ
     banks. REC shall provide either corresponding guarantees or a shareholder
     loan equal to 1/3 of the guarantee debt of EverQ. If such guarantees are
     executed by the respective banks, the guaranteeing Parties shall share the
     burden pro rata to their shareholding in EverQ at the time of such
     execution.

               (e) No Additional Obligation. No Party shall be required to
     provide loan financing, equity contributions or any form of guarantee or
     credit support for repayment for any funding obtained by EverQ, above the
     obligations described in Section 3.5 (c) and 3.5 (d). For the avoidance of
     doubt, the Capacity Expansion referenced in Section 3.5 (a) does not oblige
     any Party to provide additional funding to EverQ. Additionally, for the
     avoidance of doubt, in each capital increase (including any issuance of any
     instruments convertible into shares), all Parties shall be entitled to
     subscribe to new shares (or any instruments convertible into shares) at the
     same price and terms and pro rata to their shareholdings in EverQ at such
     time."

6.   Section 3.6 shall be reworded as follows:

          "3.6 Directors

     EverQ shall have three (3) Directors. Any Party holding an ownership
     interest of more than [****] % in EverQ shall have the right to appoint one
     (1) Director. As long as Evergreen is entitled to nominate one Director,
     the Director nominated by Evergreen shall be elected as Chairman of the
     Supervisory Board. Each Party shall cause each Director appointed by it to
     perform his duties as a Director fully in compliance with the terms of this
     Agreement and the Articles of Association. None of the Parties shall be
     excused from the performance of this Agreement on account of the failure to
     control such Director nominated and appointed by it."

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                                       -4-


7.   Section 4.1 shall be reworded as follows:

          "4.1 Restrictions on Transfer; Exceptions.

     Each of the Parties agrees that it shall not, either directly or
     indirectly, sell, transfer or dispose of ("TRANSFER") any Shares during the
     term of this Agreement, without complying with the terms of this ARTICLE 4;
     provided, however, that the foregoing restrictions shall not apply to
     Transfers of shares or other equity interests of EverQ (i) by any Party to
     any Affiliate of such Party or (ii) from any Affiliate of such Party to
     such Party or to any Affiliate of such Party, provided always that the
     transferring Party remains, and the transferee of such transferred Shares
     or equity interests agrees in the appropriate form to be, bound by the
     terms of this Agreement to the same extent that the original Parties are
     bound thereby. For the avoidance of doubt, a Change of Control in a Party
     does not trigger the other Parties' right of first refusal under this
     SECTION 4.1."

8.   The following sentence shall be added as new Section 5.6 (d):

     "(d) EverQ shall be entitled to enforce any agreement to which it is a
     party unless such agreement is terminated in accordance with its terms or
     this Article V."

The Amendments of the Master Joint Venture Agreement are entered into under the
conditions precedent that (i) the share capital in EverQ is increased to Euro
[****], (ii) that such capital increase is registered with the commercial
register, and (iii) that after registration of such capital increase, Evergreen
Solar, Inc., Q-Cells and REC hold shares in a total amount of Euro [****] each.


EVERGREEN SOLAR, INC.                   RENEWABLE ENERGY CORPORATION ASA

BY: /s/ Phillipp von Alvensleben        BY: /s/ Saskia Au

NAME:                                   NAME:

TITLE:                                  TITLE:



REC SOLAR GRADE SILICON LLC             EVERQ GMBH

BY: /s/ Saskia Au                       BY: /s/ Michael Naschke

NAME:                                   NAME:

TITLE:                                  TITLE:



Q-CELLS AG

BY: /s/ Kathrin von Pochhammer

NAME:

TITLE: