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                       AMENDMENT TO FORBEARANCE AGREEMENT

         THIS AMENDMENT TO FORBEARANCE AGREEMENT (this "AGREEMENT") is made this
17th day of January, 2003 by and among:

         SILICON VALLEY BANK (the "LENDER"), a bank organized under the laws of
         the State of California with its principal place of business at 3003
         Tasman Drive, Santa Clara, California and with a loan production office
         located at 2221 Washington Street, Suite 200, Newton, Massachusetts
         doing business under the name "Silicon Valley East";

         SATCON TECHNOLOGY CORPORATION, SATCON POWER SYSTEMS, INC., SATCON
         APPLIED TECHNOLOGY, INC., SATCON ELECTRONICS, INC., AND SATCON POWER
         SYSTEMS CANADA LTD. (individually and collectively, jointly and
         severally, the "BORROWER"), Delaware corporations (other than SatCon
         Power Systems Canada Ltd. which is organized under the laws of the
         Province of Ontario, Canada) with offices located at 161 First Street,
         Cambridge, Massachusetts;


                                   BACKGROUND

         Reference is made to the loan arrangement maintained between the Lender
and the Borrower, evidenced by, among other things, a certain Loan and Security
Agreement dated as of September 13, 2002 (the "LOAN AGREEMENT"), as affected by
a certain Forbearance Agreement entered into by the Lender and the Borrower
dated as of December 19, 2002 (the "FORBEARANCE AGREEMENT"). Hereinafter, the
Loan Agreement, the Forbearance Agreement and all documents, instruments, and
agreements incidental thereto shall be referred to collectively as the "LOAN
Documents". Capitalized terms used in this Agreement and not otherwise defined
herein shall have the meanings as defined in the Forbearance Agreement.

         The Borrower has requested that the Lender revise certain terms of the
Forbearance Agreement relating to Termination Events and Lender has agreed, but
only upon the terms and conditions set forth herein.

         Accordingly, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, it is hereby agreed by and between
the Lender and the Borrower, as follows:


                         ACKNOWLEDGMENT OF INDEBTEDNESS

         1.   The Borrower hereby acknowledges and agrees that it is
              unconditionally liable to the Lender for the following amounts in
              accordance with the terms of the Loan Documents and this
              Agreement, as of January 16, 2003:

              (a)  Revolving Loans:

                       Principal:                 $1,479,291.15


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              (b)  For any additional principal advances and all interest
                   heretofore or hereafter accruing, and all fees, penalties,
                   costs, expenses, and costs of collection (including
                   attorneys' fees and expenses) heretofore or hereafter
                   incurred by the Lender in connection with the Loan Documents.

              (c)  Hereinafter all amounts due as set forth in this Paragraph 1
                   and all other amounts payable pursuant to the terms of the
                   Loan Documents, shall be referred to collectively as the
                   "Obligations".

                                WAIVER OF CLAIMS

         2.   The Borrower hereby acknowledges and agrees that it has no
              offsets, defenses, claims, or counterclaims against the Lender, or
              its officers, directors, employees, attorneys, representatives,
              parent, affiliates, predecessors, successors, or assigns with
              respect to the Loan Documents, the Obligations, or otherwise, and
              that if the Borrower now has, or ever did have, any offsets,
              defenses, claims, or counterclaims against the Lender, or its
              officers, directors, employees, attorneys, representatives,
              parent, affiliates, predecessors, successors, or assigns, whether
              known or unknown, at law or in equity, from the beginning of the
              world through this date and through the time of execution of this
              Agreement, all of them are hereby expressly WAIVED, and the
              Borrower hereby RELEASES the Lender, and its officers, directors,
              employees, attorneys, representatives, parent, affiliates,
              predecessors, successors, and assigns from any liability therefor.

                         RATIFICATION OF LOAN DOCUMENTS

         3.   The Borrower hereby ratifies, confirms, and reaffirms all and
              singular the terms and conditions of the Loan Documents. The
              Borrower further acknowledges and agrees that, except as
              specifically modified in this Agreement, all terms and conditions
              of the Loan Documents shall remain in full force and effect
              including, without limitation, the requirement of the payment of
              the Additional Fees set forth in Section 11 of the Forbearance
              Agreement.

                       AMENDMENTS TO FORBEARANCE AGREEMENT

         4.   The Forbearance Agreement is hereby amended as follows:

              (i)  Section 11 (ii) of the Forbearance Agreement is hereby
                   amended by deleting the text "January 15, 2003" set forth
                   therein and substituting the text "January 25, 2003 therefor.

              (ii) Section 12 (a) of the Forbearance Agreement is hereby amended
                   by deleting same in its entirety and substituting the text
                   "January 25, 2003" therefor.


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                                ENTIRE AGREEMENT

         5.   This Agreement shall be binding upon the Borrower and the
              Borrower's respective employees, representatives, successors, and
              assigns, and shall inure to the benefit of the parties and their
              successors and assigns. This Agreement and all documents,
              instruments, and agreements executed in connection herewith
              incorporate all of the discussions and negotiations between the
              Borrower and the Lender, either expressed or implied, concerning
              the matters included herein and in such other documents,
              instruments and agreements, any statute, custom, or usage to the
              contrary notwithstanding.

                            CONSTRUCTION OF AGREEMENT

         6.   In connection with the interpretation of this Agreement and all
              other documents, instruments, and agreements incidental hereto:

              (a)  All rights and obligations hereunder and thereunder,
                   including matters of construction, validity, and performance,
                   shall be governed by and construed in accordance with the law
                   of the Commonwealth of Massachusetts and are intended to take
                   effect as sealed instruments.

              (b)  In the event of any inconsistency between the provisions of
                   this Agreement and any other document, instrument, or
                   agreement entered into by and between the Lender and the
                   Borrower, the provisions of this Agreement shall govern and
                   control.


                         ILLEGALITY OR UNENFORCEABILITY

         7.   Any determination that any provision or application of this
              Agreement is invalid, illegal, or unenforceable in any respect, or
              in any instance, shall not affect the validity, legality, or
              enforceability of any such provision in any other instance, or the
              validity, legality, or enforceability of any other provision of
              this Agreement.


                               INFORMED EXECUTION

         8.   The Borrower warrants and represents to the Lender that the
              Borrower has read and understands all of the terms and conditions
              of this Agreement, intends to be bound by the terms and conditions
              of this Agreement, and is executing this Agreement freely and
              voluntarily, without duress, after consultation with independent
              counsel of its own selection.


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         IN WITNESS WHEREOF, this Agreement has been executed as of the 17th day
of January, 2003.

                                   "BORROWER"

                           SATCON TECHNOLOGY CORPORATION

                           By: /s/ Ralph M. Norwood
                               --------------------
                           Title: Vice President and Chief Financial Officer


                           SATCON POWER SYSTEMS, INC.

                           By: /s/ Ralph M. Norwood
                               --------------------
                           Title: Vice President and Chief Financial Officer


                           SATCON APPLIED TECHNOLOGY, INC.

                           By: /s/ Ralph M. Norwood
                               --------------------
                           Title: Vice President and Chief Financial Officer

                           SATCON ELECTRONICS, INC.

                           By: /s/ Ralph M. Norwood
                               --------------------
                           Title: Vice President and Chief Financial Officer

                           SATCON POWER SYSTEMS CANADA LTD

                           By: /s/ Ralph M. Norwood
                               --------------------
                           Title: Vice President and Chief Financial Officer

                           "LENDER"

                           SILICON VALLEY BANK

                           By: /s/ John K. Peck
                               --------------------
                           Title: Vice President


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