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                                                                   EXHIBIT 10.47

                     SIXTH AMENDMENT TO AMENDED AND RESTATED
                     ACCOUNTS RECEIVABLE FINANCING AGREEMENT

       This Sixth Amendment (this "Sixth Amendment") to the Amended and Restated
Accounts Receivable Financing Agreement is entered into as of December 12, 2003,
by and among (i) SILICON VALLEY BANK, a California-chartered bank, with its
principal place of business at 3003 Tasman Drive, Santa Clara, California 95054
and with a loan production office located at One Newton Executive Park, Suite
200, 2221 Washington Street, Newton, Massachusetts 02462, doing business under
the name "Silicon Valley East" ("Bank") and (ii) SATCON TECHNOLOGY CORPORATION,
a Delaware corporation with offices located at 161 First Street, Cambridge,
Massachusetts (FAX 617-661-3373); SATCON POWER SYSTEMS, INC., Delaware
corporation with offices located at 161 First Street, Cambridge, Massachusetts;
SATCON APPLIED TECHNOLOGY, INC., a Delaware corporation with offices located at
161 First Street, Cambridge, Massachusetts; SATCON ELECTRONICS, INC., a Delaware
corporation with offices located at 161 First Street, Cambridge, Massachusetts;
and SATCON POWER SYSTEMS CANADA LTD. a corporation organized under the laws of
the Province of Ontario, Canada with offices located at 161 First Street,
Cambridge, Massachusetts (individually and collectively, jointly and severally,
"Borrower").

1. DESCRIPTION OF EXISTING INDEBTEDNESS AND OBLIGATIONS. Among other
indebtedness and obligations which may be owing by Borrower to Bank, Borrower is
indebted to Bank pursuant to a certain Amended and Restated Accounts Receivable
Financing Agreement dated as of April 4, 2003, as amended by a certain First
Amendment to Amended and Restated Accounts Receivable Financing Agreement dated
as of June 24, 2003, as further amended by a certain Second Amendment to Amended
and Restated Accounts Receivable Financing Agreement dated as of August 11,
2003, as further amended by a certain Third Amendment to Amended and Restated
Accounts Receivable Financing Agreement dated as of September 2, 2003, as
further amended by a certain Fourth Amendment to Amended and Restated Accounts
Receivable Financing Agreement dated as of September 10, 2003, and as further
amended by a certain Fifth Amendment to Amended and Restated Accounts Receivable
Financing Agreement dated as of October 20, 2003 (as amended from time to time,
the "Loan Agreement"). Capitalized terms used but not otherwise defined herein
shall have the same meaning as in the Loan Agreement.

2. DESCRIPTION OF COLLATERAL. Repayment of the Obligations is secured by the
Collateral as described in the Loan Agreement (together with any other
collateral security granted to Bank, the "Security Documents").

Hereinafter, the Security Documents, together with all other documents
evidencing or securing the Obligations shall be referred to as the "Existing
Loan Documents".

3. DESCRIPTION OF CHANGE IN TERMS.

       A. Modifications to Loan Agreement.

            1.   The Loan Agreement shall be amended by deleting the following
                 definitions appearing in Section 1, thereof:

                      ""ADJUSTED TANGIBLE NET WORTH" shall mean the excess of
                      total assets over total liabilities, determined in
                      accordance with generally accepted accounting principles,
                      with the following adjustments: (A) there shall be
                      excluded from assets: (i) notes, accounts receivable and
                      other obligations owing to Borrower from its officers or
                      other affiliates, (ii) all assets which would be
                      classified as intangible assets under generally accepted
                      accounting principles, including without limitation
                      goodwill, licenses, patents, trademarks, trade names,
                      copyrights, capitalized software and organizational costs,
                      licenses and franchises, (iii) the value of Borrower's
                      investment in Beacon Power Corporation, and (iv) the value
                      of Borrower's warrants to purchase Beacon

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                      Power Corporation and (B) there shall be excluded from
                      liabilities: all indebtedness which is subordinated to the
                      Obligations under a subordination agreement in form
                      specified by Bank or by language in the instrument
                      evidencing the indebtedness which is acceptable to Bank in
                      its sole discretion.

                      "ADVANCE RATE" is eighty percent (80.0%) net of Deferred
                      Revenue and offsets related to each specific Account
                      Debtor.

                      "APPLICABLE RATE" is a per annum rate equal to the Prime
                      Rate plus four percent (4.0%).

                      "FACILITY AMOUNT" is Five Million Dollars ($5,000,000.00),
                      provided, however, than until the occurrence of each of
                      Capitalization Event No. 1 and Capitalization Event No. 2,
                      and provided that no Event of Default has occurred, the
                      maximum Facility Amount shall be Three Million One Hundred
                      Twenty Five Thousand Dollars ($3,125,000.00).

                      "FACILITY PERIOD" is the period beginning on this date and
                      continuing until one year from the date of this Agreement,
                      unless the period is terminated sooner by Bank with notice
                      to Borrower or by Borrower pursuant to Section 4.3.

                      "PRIME RATE" is the greater of (i) 4.75% or (ii) Bank's
                      most recently announced "Prime Rate," even if it is not
                      Bank's lowest rate."

                 and inserting in lieu thereof the following:

                      ""ADJUSTED TANGIBLE NET WORTH" shall mean the excess of
                      total assets over total liabilities, determined in
                      accordance with generally accepted accounting principles,
                      with the following adjustments: (A) there shall be
                      excluded from assets: (i) notes, accounts receivable and
                      other obligations owing to Borrower from its officers or
                      other affiliates, and (ii) all assets which would be
                      classified as intangible assets under generally accepted
                      accounting principles, including without limitation
                      goodwill, licenses, patents, trademarks, trade names,
                      copyrights, capitalized software and organizational costs,
                      licenses and franchises, and (B) there shall be excluded
                      from liabilities all Subordinated Debt.

                      "ADVANCE RATE" is eighty percent (80.0%) net of Deferred
                      Revenue and offsets related to each specific Account
                      Debtor, or such other percentage as Bank establishes under
                      Section 2.2; provided however, if Borrower is unable to
                      maintain an Adjusted Quick Ratio of at least 1.0 to 1.0,
                      then the Advance Rate will be eighty percent (80.0%) net
                      of any offsets related to each specific Account Debtor,
                      including, without limitation, Deferred Revenue.

                      "APPLICABLE RATE" is a per annum rate equal to the
                      aggregate of the Prime Rate plus one and one half of one
                      percent (1.5%), provided however, if Borrower is unable to
                      maintain an Adjusted Quick Ratio of at least 1.0 to 1.0 as
                      of the end of any Reconciliation Period, then the
                      Applicable Rate will be a per annum rate equal to the
                      aggregate of the Prime Rate plus three percent (3.0%)
                      effective as of such Reconciliation Period and for each
                      Reconciliation Period thereafter. In the event that
                      Borrower achieves an Adjusted Quick Ratio of at least 1.0
                      to 1.0 thereafter, then the Applicable Rate shall reduce
                      to the aggregate of the Prime Rate plus one and one half
                      of one percent (1.5%), effective for each Reconciliation
                      Period after Borrower delivers to Bank satisfactory
                      evidence that

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                      Borrower has achieved such Adjusted Quick Ratio.

                      "FACILITY AMOUNT" is Six Million Two Hundred Fifty
                      Thousand Dollars ($6,250,000.00).

                      "FACILITY PERIOD" is the period beginning on the 2003
                      Closing Date and continuing until the date which is 364
                      days after the 2003 Closing Date, unless the period is
                      terminated sooner by Bank with notice to Borrower or by
                      Borrower pursuant to Section 4.3.

                      "PRIME RATE" is the greater of (i) 4.00% or (ii) Bank's
                      most recently announced "Prime Rate," even if it is not
                      Bank's lowest rate."

            2.   The Loan Agreement shall be amended by inserting the following
                 definitions, in alphabetical order, in Section 1, thereof:

                      ""2003 CLOSING DATE" is December 12, 2003.

                      "ADJUSTED QUICK RATIO" is the ratio of Quick Assets to
                      Current Liabilities minus Deferred Revenue.

                      "CURRENT LIABILITIES" is all obligations and liabilities
                      of Borrower to Bank, plus, without duplication, the
                      aggregate amount of Borrower's Total Liabilities which
                      mature within one (1) year.

                      "QUICK ASSETS" is, on any date, the Borrower's
                      consolidated, unrestricted cash, cash equivalents, net
                      accounts receivable and investments with maturities of
                      fewer than 12 months determined according to GAAP.

                      "TOTAL LIABILITIES" is on any day, obligations that
                      should, under GAAP, be classified as liabilities on
                      Borrower's consolidated balance sheet, including all
                      Indebtedness, and current portion Subordinated Debt
                      allowed to be paid, but excluding all other Subordinated
                      Debt.

                      "UNUSED LINE FEE" is defined in Section 3.8."

            3.   The Loan Agreement shall be amended by deleting the following
                 text appearing in Section 3.4 thereof:

                      "On each Reconciliation Day, Borrower will pay to Bank a
                      Collateral Handling Fee, equal to: (a) 0.55% per month of
                      the average daily Financed Receivable Balance outstanding
                      during the applicable Reconciliation Period, prior the
                      occurrence of Capitalization Event No. 1 and
                      Capitalization Event No. 2, and (b) 0.45% per month of the
                      average daily Financed Receivable Balance outstanding
                      during the applicable Reconciliation Period, after the
                      occurrence of Capitalization Event No. 1 and
                      Capitalization Event No. 2."

                 and inserting in lieu thereof the following:

                      "On each Reconciliation Day, Borrower will pay to Bank a
                      Collateral Handling Fee, equal to 0.20% per month of the
                      average daily Financed Receivable Balance outstanding
                      during the applicable Reconciliation Period; provided
                      however, if Borrower is unable to maintain an Adjusted
                      Quick Ratio of at least 1.0 to 1.0, then the Collateral
                      Handling Fee will be equal to 0.25% per month of

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                      the average daily Financed Receivable Balance outstanding
                      during the applicable Reconciliation Period effective as
                      of such Reconciliation Period and for each Reconciliation
                      Period thereafter. In the event that Borrower achieves an
                      Adjusted Quick Ratio of at least 1.0 to 1.0 thereafter,
                      then the Collateral Handing Fee shall reduce to 0.20% per
                      month of the average daily Financed Receivable Balance
                      outstanding during the applicable Reconciliation Period,
                      for each Reconciliation Period after Borrower delivers to
                      Bank satisfactory evidence that Borrower has achieved such
                      Adjusted Quick Ratio."

            4.   The Loan Agreement shall be amended by inserting the following
                 new Section 3.8 immediately following Section 3.7 thereof:

                           "3.8 UNUSED LINE FEE. In the event, in any calendar
                      quarter after the 2003 Closing Date, the average daily
                      principal balance of Advances outstanding during the
                      quarter is less than $5,000,000, Borrower shall pay Bank
                      an unused line fee in an amount equal to 0.50% per annum
                      on the difference between $5,000,000 and the average daily
                      principal balance of the Advances outstanding during the
                      quarter (the "Unused Line Fee"), which Unused Line Fee
                      shall be computed and paid quarterly, in arrears, on the
                      first day of the following quarter."

            5.   The Loan Agreement shall be amended by deleting the following
                 text appearing in Section 4.3 thereof, entitled "Early
                 Termination of Agreement":

                      "If this Agreement is terminated (A) by Bank in accordance
                      with clause (ii) in the foregoing sentence or (B) by
                      Borrower for any reason, Borrower shall pay to Bank a
                      termination fee in an amount equal to One Hundred Thousand
                      Dollars ($100,000.00) (the "Early Termination Fee")."

                 and inserting in lieu thereof the following:

                      "If this Agreement is terminated prior to six (6) months
                      after the 2003 Closing Date (A) by Bank in accordance with
                      clause (ii) in the foregoing sentence or (B) by Borrower
                      for any reason, Borrower shall pay to Bank a termination
                      fee in an amount equal to Twenty-Five Thousand Dollars
                      ($25,000.00) (the "Early Termination Fee")."

            6.   The Loan Agreement shall be amended by deleting the following
                 text appearing in Section 6.3(D) thereof:

                      "(ii) as soon as available, but no later than one hundred
                      twenty (120) days after the end of Borrower's fiscal year,
                      audited consolidated financial statements prepared under
                      GAAP, consistently applied, together with an unqualified
                      opinion on the financial statements from an independent
                      certified public accounting firm acceptable to Bank;"

                 and inserting in lieu thereof the following:

                      "(ii) as soon as available, but no later than ninety (90)
                      days after the end of Borrower's fiscal year, audited
                      consolidated financial statements prepared under GAAP,
                      consistently applied, together with an opinion on the
                      financial statements from an independent certified public
                      accounting firm acceptable to Bank;"

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            7.   The Loan Agreement shall be amended by deleting the following
                 text appearing in Section 6.3(M) thereof:

                      "(M) Maintain at all times, to be tested monthly, an
                      Adjusted Tangible Net Worth equal to or greater than the
                      aggregate of: (a)(i) Four Million Five Hundred Thousand
                      Dollars ($4,500,000.00) as of the month ended August 31,
                      2003; (ii) Four Million Eight Hundred Thousand Dollars
                      ($4,800,000.00) as of the month ending September 30, 2003;
                      (iii) Three Million Seven Hundred Thousand Dollars
                      ($3,700,000.00) as of the month ending October 31, 2003;
                      (iv) Three Million Six Hundred Thousand Dollars
                      ($3,600,000.00) as of the month ending November 30, 2003;
                      (v) Four Million Seven Hundred Thousand Dollars
                      ($4,700,000.00) as of the month ending December 31, 2003;
                      (vi) Three Million Six Hundred Thousand Dollars
                      ($3,600,000.00) as of the month ending January 31, 2004;
                      (vii) Three Million Five Hundred Thousand Dollars
                      ($3,500,000.00) as of the month ending February 28, 2004
                      and for each month thereafter, plus (b) 100% of the amount
                      of proceeds received by Borrower in connection with any
                      issuance of equity or subordinated debt, including
                      Capitalization Event No. 1 and Capitalization Event No. 2,
                      minus (c) a maximum of Seven Hundred Thousand Dollars
                      ($700,000.00) in past and current expenses approved by the
                      Bank which have been netted out of the H.C. Wainwright
                      equity/sub debt financing upon the closing of same."

                 and inserting in lieu thereof the following:

                      "(M) Maintain: (a) as of the last day of each month
                      (unless such day is also the last day of a quarter), an
                      Adjusted Tangible Net Worth of at least Eight Million
                      Eight Hundred Thousand Dollars ($8,800,000.00), and (b) as
                      of the last day of each quarter, an Adjusted Tangible Net
                      Worth of at least Ten Million Three Hundred Thousand
                      Dollars ($10,3000,000.00), to be tested monthly."

            8.   The Loan Agreement shall be amended by deleting the following
                 text appearing in Section 6.4(A) thereof:

                      "(A) Assign, lease, transfer, sell or grant, or permit any
                      lien or security interest in the Collateral, except for
                      transfers (i) of inventory in the ordinary course of
                      business and (ii) of worn-out or obsolete equipment."

                 and inserting in lieu thereof the following:

                      "(A) Assign, lease, transfer, sell or grant, or permit any
                      lien or security interest in the Collateral, except for
                      transfers of (i) inventory in the ordinary course of
                      business (ii) worn-out or obsolete equipment, and (iii)
                      patents and other intellectual property associated with
                      Smart Predictive Line Controller technology on terms
                      acceptable to Bank."

            9.   The Loan Agreement shall be amended by deleting the following
                 text appearing in Section 6.4(B) thereof:

                      "(B) Create, incur, assume, or be liable for any
                      indebtedness."

                 and inserting in lieu thereof the following:

                      "(B) Create, incur, assume, or be liable for any
                      indebtedness, except for fixed assets currently financed
                      elsewhere, as well as additional indebtedness up to a

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                      maximum amount of $1,000,000.00 in connection with the
                      financing of Borrower's existing equipment, provided that
                      such indebtedness is on terms and conditions reasonably
                      acceptable to Bank."

4. FEES. Borrower shall pay to Bank a commitment fee equal to Twenty Three
Thousand Two Hundred Fifty Dollars ($23,250.00), which fee shall be due on the
date hereof and shall be deemed fully earned as of the date hereof. The Borrower
shall also reimburse Bank for all legal fees and expenses incurred in connection
with this amendment to the Existing Loan Documents.

5. RATIFICATION OF INTELLECTUAL PROPERTY SECURITY AGREEMENT. Borrower hereby
ratifies, confirms and reaffirms, all and singular, the terms and conditions of
a certain Intellectual Property Security Agreement dated as of December 19, 2002
between Borrower and Bank, and acknowledges, confirms and agrees that said
Intellectual Property Security Agreement contains an ACCURATE and COMPLETE
listing of all Intellectual Property Collateral as defined in said Intellectual
Property Security Agreement, shall remain in full force and effect.

6. CONSISTENT CHANGES. The Existing Loan Documents are hereby amended wherever
necessary to reflect the changes described above.

7. RATIFICATION OF LOAN DOCUMENTS. Borrower hereby ratifies, confirms, and
reaffirms all terms and conditions of all security or other collateral granted
to the Bank, and confirms that the indebtedness secured thereby includes,
without limitation, the Obligations.

8. NO DEFENSES OF BORROWER. Borrower hereby acknowledges and agrees that
Borrower has no offsets, defenses, claims, or counterclaims against Bank with
respect to the Obligations, or otherwise, and that if Borrower now has, or ever
did have, any offsets, defenses, claims, or counterclaims against Bank, whether
known or unknown, at law or in equity, all of them are hereby expressly WAIVED
and Borrower hereby RELEASES Bank from any liability thereunder.

9. CONTINUING VALIDITY. Borrower understands and agrees that in modifying the
existing Obligations, Bank is relying upon Borrower's representations,
warranties, and agreements, as set forth in the Existing Loan Documents. Except
as expressly modified pursuant to this Sixth Amendment, the terms of the
Existing Loan Documents remain unchanged and in full force and effect. Bank's
agreement to modifications to the existing Obligations pursuant to this Sixth
Amendment in no way shall obligate Bank to make any future modifications to the
Obligations. Nothing in this Sixth Amendment shall constitute a satisfaction of
the Obligations. It is the intention of Bank and Borrower to retain as liable
parties all makers of Existing Loan Documents, unless the party is expressly
released by Bank in writing. No maker will be released by virtue of this Sixth
Amendment.

10. COUNTERSIGNATURE. This Sixth Amendment shall become effective only when it
shall have been executed by Borrower and Bank (provided, however, in no event
shall this Sixth Amendment become effective until signed by an officer of Bank
in California).

            [THE REMAINDER OF THIS PAGE IS INTENTIONALLY LEFT BLANK]

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       This Sixth Amendment is executed as a sealed instrument under the laws of
the Commonwealth of Massachusetts as of the date first written above.

BORROWER:
SATCON  TECHNOLOGY CORPORATION


By /s/ RALPH M. NORWOOD
   -----------------------------------------
Name: RALPH M. NORWOOD
     ---------------------------------------
Title VP & CFO
      --------------------------------------


SATCON POWER SYSTEMS, INC.


By /s/ RALPH M. NORWOOD
   -----------------------------------------
Name: RALPH M. NORWOOD
     ---------------------------------------
Title VP & CFO
      --------------------------------------


SATCON APPLIED TECHNOLOGY, INC.


By /s/ RALPH M. NORWOOD
   -----------------------------------------
Name: RALPH M. NORWOOD
     ---------------------------------------
Title VP & CFO
      --------------------------------------


SATCON ELECTRONICS, INC.


By /s/ RALPH M. NORWOOD
   -----------------------------------------
Name: RALPH M. NORWOOD
     ---------------------------------------
Title VP & CFO
      --------------------------------------


SATCON POWER SYSTEMS CANADA LTD.


By /s/ RALPH M. NORWOOD
   -----------------------------------------
Name: RALPH M. NORWOOD
     ---------------------------------------
Title VP & CFO
      --------------------------------------

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BANK:
SILICON VALLEY BANK


By DAVID REICH
  ------------------------------------------
Title SVP
      --------------------------------------