UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM 8-K
                                 CURRENT REPORT
                     Pursuant to Section 13 or 15(d) of the
                         Securities Exchange Act of 1934

       Date of report (Date of earliest event reported): December 27, 2004

                            BEACON POWER CORPORATION
                            ------------------------
               (Exact Name of Registrant as Specified in Charter)

         DELAWARE                       001-16171             04-3372365
         --------                       ---------             ----------
(State or Other Jurisdiction of  (Commission File Number)   (IRS Employer
      Incorporation)                                      Identification No.)

      234 BALLARDVALE STREET
          WILMINGTON, MA                                         01887
      ----------------------                                     -----
(Address of Principal Executive Offices)                      (Zip Code)

        Registrant's telephone number, including area code: 978-694-9121


Check the appropriate box below if the Form 8-K filing is intended to
simultaneously satisfy the filing obligation of the registrant under any of the
following provisions:

[ ] Written communications pursuant to Rule 425 under the Securities Act (17 CFR
230.425)

[ ] Soliciting  material  pursuant to Rule 14a-12 under the Exchange Act (17 CFR
240.14a-12)

[ ] Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange
Act (17 CFR 240.14d-2(b))

[ ] Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange
Act (17 CFR 240.13e-4(c))






                Section 1 - Registrant's Business and Operations

Item 1.01.  Entry into a Material Definitive Agreement.

     On December 27, 2004, Beacon Power Corporation (the  "Registrant")  entered
into an Assignment  with CRT Capital Group LLC (the  "Transferee")  for the sale
and transfer of the Amended and Restated  Warrant  (the  "Warrant")  dated as of
October  18,  2004  issued by  Evergreen  Solar,  Inc.,  a Delaware  corporation
("Evergreen"),  for  shares  of common  stock,  $.01 par  value  per  share,  of
Evergreen  held by the  Registrant.  The  Registrant  purchased the Warrant from
Evergreen for $100,000.00.  The aggregate  purchase price paid by the Transferee
to the Registrant for the sale and transfer of the Warrant is $1,800,000.00.

Item 9. Financial Statements and Exhibits.

     (c) Exhibits

     10.1 Assignment,   dated  December  27,  2004,  executed  by  Beacon  Power
          Corporation and accepted by CRT Capital Group LLC.


                                    Signature

Pursuant  to the  requirements  of the  Securities  Exchange  Act of  1934,  the
registrant  has duly  caused  this  report  to be  signed  on its  behalf by the
undersigned hereunto duly authorized.


                                       BEACON POWER CORPORATION


Date:  December 29, 2004                 By:  /s/ F. William Capp
                                              -------------------
                                       Name:  F. William Capp
                                      Title:  President and Chief Executive
                                              Officer



                                  Exhibit Index

Exhibit No.   Description
- -----------   -----------
10.1          Assignment, dated December 27, 2004, executed by Beacon Power
              Corporation and accepted by CRT Capital Group LLC.