<PAGE>
                                                                    Exhibit 10.4


THE SECURITIES EVIDENCED BY THIS WARRANT CERTIFICATE HAVE NOT BEEN REGISTERED
UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), AND MAY NOT
BE SOLD, TRANSFERRED, OR ASSIGNED OR OFFERED FOR SALE OR OTHERWISE DISTRIBUTED
UNLESS THERE IS AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT
COVERING SUCH SECURITIES, THE SALE IS MADE IN COMPLIANCE WITH RULE 144 UNDER THE
SECURITIES ACT, OR THE COMPANY RECEIVES AN OPINION OF COUNSEL FOR THE HOLDER OF
SUCH SECURITIES REASONABLY SATISFACTORY TO THE COMPANY STATING THAT SUCH SALE,
TRANSFER OR ASSIGNMENT IS EXEMPT FROM THE REGISTRATION REQUIREMENTS OF THE
SECURITIES ACT.

No.: ______

                                     WARRANT
                            TO PURCHASE COMMON STOCK
                                       OF
                              EVERGREEN SOLAR, INC.

(void after ______________(1))


1. Issuance of Warrant. FOR VALUE RECEIVED, from and after the Commencement
Time, and subject to the terms and conditions herein set forth, the Holder (as
defined below) is entitled to purchase from Evergreen Solar, Inc., a Delaware
corporation (the "Company"), at any time before 5:00 p.m. New York City time on
________________(2) (the "Termination Date"), the Warrant Stock (as defined
below) at a price per share equal to the Warrant Price (as defined below) upon
exercise of this Warrant pursuant to Section 6 hereof.

2. Definitions. As used in this Warrant, the following terms have the
definitions ascribed to them below:

      (a) "Business Day" means any day other than a Saturday, Sunday or other
day on which the national or state banks located in the Commonwealth of
Massachusetts, the State of New York or the District of Columbia are authorized
to be closed.

      (b) "Commencement Time" means _____________________(3).

      (c) "Common Stock" means the Company's Common Stock, $.01 par value per
share.

      (d) "Holder" means Beacon Power Corporation, or its assigns.

      (e) "Person" means any individual, corporation, partnership, limited
liability company, trust, incorporated or unincorporated association, joint
venture, joint stock company, governmental authority or other entity of any
kind, and shall include any successor (by merger or otherwise) of such entity.

      (f) "Warrant Price" means _______________(4) per share subject to
adjustment under Section 3.

-----------------------
(1) Insert date which is 3rd anniversary of date Warrant is issued.

(2) Insert date which is 3rd anniversary of date Warrant is issued.

(3) Insert date of issue of Warrant.

(4) Insert dollar amount which is the Price Per Share in the equity financing in
connection with this Warrant is issued, plus $2.25.
<PAGE>
      (g) "Warrant Stock" means the shares of Common Stock (or other securities)
purchasable upon exercise of this Warrant. The total number of shares to be
issued upon the exercise of this Warrant shall be 2,400,000 shares, subject to
adjustment under Section 3.

3. Adjustments and Notices. The Warrant Price and/or the Warrant Stock shall be
subject to adjustment from time to time in accordance with this Section 3. The
Warrant Price and/or the Warrant Stock shall be adjusted to reflect all of the
following events that occur on or after the Commencement Time.

      (a) Subdivision, Stock Dividends or Combinations. In case the Company
shall at any time subdivide the outstanding shares of the Common Stock or shall
issue a stock dividend with respect to the Common Stock, the Warrant Price in
effect immediately prior to such subdivision or the issuance of such dividend
shall be proportionately decreased, and the number of shares of Warrant Stock
for which this Warrant may be exercised immediately prior to such subdivision or
the issuance of such dividend shall be proportionately increased. In case the
Company shall at any time combine the outstanding shares of the Common Stock,
the Warrant Price in effect immediately prior to such combination shall be
proportionately increased, and the number of shares of Warrant Stock for which
this Warrant may be exercised immediately prior to such combination shall be
proportionately decreased. In each of the foregoing cases, the adjustment shall
be effective at the close of business on the date of such subdivision, dividend
or combination, as the case may be.

      (b) Reclassification, Exchange, Substitution, In-Kind Distribution. Upon
any reclassification, exchange, substitution or other event that results in a
change of the number and/or class of the securities issuable upon exercise or
conversion of this Warrant or upon the payment of a dividend in securities or
property other than shares of the Common Stock, the Holder shall be entitled to
receive, upon exercise of this Warrant, the number and kind of securities and
property that Holder would have received if this Warrant had been exercised
immediately before the record date for such reclassification, exchange,
substitution, or other event or immediately prior to the record date for such
dividend. The Company or its successor shall promptly issue to Holder a new
warrant for such new securities or other property. The new warrant shall provide
for adjustments which shall be as nearly equivalent as may be practicable to the
adjustments provided for in this Section 3 including, without limitation,
adjustments to the Warrant Price and to the number of securities or property
issuable upon exercise or conversion of the new warrant. The provisions of this
Section 3(b) shall similarly apply to successive reclassifications, exchanges,
substitutions, or other events and successive dividends.

      (c) Reorganization, Merger etc. In case of any merger or consolidation of
the Company into or with another corporation where the Company is not the
surviving corporation, or sale, transfer or lease (but not including a transfer
or lease by pledge or mortgage to a bona fide lender) of all or substantially
all of the assets of the Company, the Company, or such successor or purchasing
corporation, as the case may be, shall, as a condition to closing any such
reorganization, merger or sale, duly execute and deliver to the Holder hereof a
new warrant so that the Holder shall have the right to receive, at a total
purchase price not to exceed that payable upon the exercise or conversion of the
unexercised portion of this Warrant, and in lieu of the shares of Warrant Stock
theretofore issuable upon exercise or conversion of this Warrant, the kind and
amount of shares of stock, other securities, money and property that would have
been receivable upon such reorganization, merger or sale by the Holder with
respect to the Warrant Stock if this Warrant had been exercised immediately
before the consummation of such transaction. Such new warrant shall provide for
adjustments that shall be as nearly equivalent as may be practicable to the
adjustments provided for in this Section 3. The provisions of this subparagraph
(c) shall similarly apply to successive transactions of the type described in
this subparagraph (c).

      (d) Certificate of Adjustment. In each case of an adjustment or
readjustment of the Warrant

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<PAGE>
Price, the Company, at its own expense, shall cause its Chief Financial Officer
to compute such adjustment or readjustment in accordance with the provisions
hereof and prepare a certificate showing such adjustment or readjustment, and
shall mail such certificate, by first class mail, postage prepaid, to the
Holder. The certificate shall set forth such adjustment or readjustment, showing
in detail the facts upon which such adjustment or readjustment is based. No
adjustment of the Warrant Price shall be required to be made unless it would
result in an increase or decrease of at least one cent, but any adjustments not
made because of this sentence shall be carried forward and taken into account in
any subsequent adjustment otherwise required hereunder.

      (e) No Impairment. The Company shall not, by amendment of its Certificate
of Incorporation or through a reorganization, transfer of assets, consolidation,
merger, dissolution, issue, or sale of securities or any other voluntary action,
avoid or seek to avoid the observance or performance of any of the terms to be
observed or performed under this Warrant by the Company, but shall at all times
in good faith assist in carrying out all of the provisions of this Section 3 and
in taking all such action as may be necessary or appropriate to protect the
Holder's rights under this Section 3 against impairment. If an event not
specified in this Section 3 occurs that has substantially the same economic
effect on the Warrant as those specifically enumerated, then Section 3 shall be
construed liberally, mutatis mutandis, in order to give the Warrant the intended
benefit of the protections provided under this Section 3. In such event, the
Company's Board of Directors shall make an appropriate adjustment in the Warrant
Price so as to protect the rights of the holders of this Warrant; provided that
no such adjustment shall increase the Warrant Price as otherwise determined
pursuant to this Section 3 or decrease the number of shares of Common Stock
issuable upon exercise of this Warrant.

      (f) Fractional Shares. No fractional shares shall be issuable upon
exercise or conversion of the Warrant and the number of shares to be issued
shall be rounded down to the nearest whole share. If a fractional share interest
arises upon any exercise or conversion of the Warrant, the Company shall
eliminate such fractional share interest by paying the Holder an amount computed
by multiplying the fractional interest by the fair market value of a full share.

4. No Shareholder Rights. This Warrant, by itself, as distinguished from any
shares purchased hereunder, shall not entitle its Holder to any of the rights of
a shareholder of the Company.

5. Reservation of Stock. The Company will reserve from its authorized and
unissued stock a sufficient number of shares to provide for the issuance of
Warrant Stock upon the exercise or conversion of this Warrant. Issuance of this
Warrant shall constitute full authority to the Company's officers who are
charged with the duty of executing stock certificates to execute and issue the
necessary certificates for shares of Warrant Stock issuable upon the exercise of
this Warrant.

6. Exercise of Warrant. This Warrant may be exercised as a whole by the Holder,
at any time from and after the Commencement Time and prior to the termination of
this Warrant, by the surrender of this Warrant, together with the Notice of
Exercise and Investment Representation Statement in the forms attached hereto as
Attachments 1 and 2, respectively, duly completed and executed at the principal
office of the Company, specifying that all of the Warrant is to be exercised and
accompanied by payment in full of the Warrant Price in wire transfer or by check
with respect to the shares of Warrant Stock being purchased. This Warrant shall
be deemed to have been exercised immediately prior to the close of business on
the date of its surrender for exercise as provided above, and the person
entitled to receive the shares of Warrant Stock issuable upon such exercise
shall be treated for all purposes as the holder of such shares of record as of
the close of business on such date. As promptly as practicable after such date,
the Company shall issue and deliver to the person or persons entitled to receive
the same a certificate or certificates for the number of full shares of Warrant
Stock issuable upon such exercise.

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7. Transfer of Warrant. This Warrant may be transferred or assigned by the
Holder hereof as a whole or in part, provided:

      (a) that the transferor provides, at the Company's request, an opinion of
counsel satisfactory to the Company that such transfer does not require
registration under the Securities Act, and

      (b) that if after such transfer there will be two or more such Warrants
(due to the Warrant having been transferred in part and not in whole), that all
persons holding a Warrant covering shares that were covered by the original
Warrant must agree in writing with each other that none of them will exercise
unless all of them exercise simultaneously, and

      (c) that unless the Company approves the transfer in writing (which
approval shall not be unreasonably withheld), that the transferee certifies to
the transferor that the transferee is not directly engaged in the research,
development or manufacture of photovoltaic wafers, solar cells, or panels.

8. Termination. This Warrant shall terminate at 5:00 p.m. New York City time on
the Termination Date.

9. Miscellaneous. This Warrant shall be governed by the laws of the State of
Delaware, as such laws are applied to contracts to be entered into and performed
entirely in Delaware by Delaware residents. The headings in this Warrant are for
purposes of convenience and reference only, and shall not be deemed to
constitute a part hereof. Neither this Warrant nor any term hereof may be
changed or waived orally, but only by an instrument in writing signed by the
Company and the Holder of this Warrant. All notices and other communications
from the Company to the Holder of this Warrant shall be delivered personally or
by facsimile transmission or mailed by first class mail, postage prepaid, to the
address or facsimile number furnished to the Company in writing by the last
Holder of this Warrant who shall have furnished an address or facsimile number
to the Company in writing, and if mailed shall be deemed given three days after
deposit in the United States mail. Upon receipt of evidence satisfactory to the
Company of the ownership of and the loss, theft, destruction or mutilation of
any Warrant and, in the case of any such loss, theft or destruction, upon
receipt of indemnity or security satisfactory to the Company or, in the case of
any such mutilation, upon surrender and cancellation of such Warrant, the
Company will make and deliver, in lieu of such lost, stolen, destroyed or
mutilated Warrant, a new Warrant of like tenor and representing the right to
purchase the same aggregate number of shares of Common Stock.



ISSUED:     ____________________, 2003


EVERGREEN SOLAR, INC.


By:__________________________________

Name:________________________________

Title:_________________________________


                                      -4-
<PAGE>
                                  Attachment 1





NOTICE OF EXERCISE

TO:  EVERGREEN SOLAR, INC.

1.   The undersigned hereby elects to purchase all shares of Warrant Stock of
     Evergreen Solar, Inc. pursuant to the terms of the attached Warrant, and
     tenders herewith payment of the purchase price in full, together with all
     applicable transfer taxes, if any.

2.   Please issue a certificate or certificates representing said shares of
     Warrant Stock in the name of the undersigned or in such other name as is
     specified below:

                  ---------------------------------------------
                 (Name in which certificate(s) are to be issued)

                  ---------------------------------------------
                                    (Address)





                             -------------------------------------
                                   (Name of Warrant Holder)


                             By:
                                ----------------------------------
                             Title:
                                   -------------------------------
                             Date signed:
                                         -------------------------




                                       -5-
<PAGE>
                                  Attachment 2

                       INVESTMENT REPRESENTATION STATEMENT

      In connection with the purchase of the shares of Warrant Stock upon
exercise of the enclosed Warrant, the undersigned hereby represents to Evergreen
Solar, Inc. (the "Company") as follows:

       (a) The securities to be received upon the exercise of the Warrant (the
"Securities") will be acquired for investment for its own account, not as a
nominee or agent, and not with a view to the sale or distribution of any part
thereof, and the undersigned has no present intention of selling, granting
participation in or otherwise distributing the same, but subject, nevertheless,
to any requirement of law that the disposition of its property shall at all
times be within its control. By executing this statement, the undersigned
further represents that it does not have any contract, undertaking, agreement or
arrangement with any person to sell, transfer, or grant participations to such
person or to any third person, with respect to any Securities issuable upon
exercise of the Warrant.

       (b) The undersigned understands that the Securities issuable upon
exercise of the Warrant at the time of issuance may not be registered under the
Securities Act of 1933, as amended (the "Securities Act"), and applicable state
securities laws, on the ground that the issuance of such securities is exempt
pursuant to Section 4(2) of the Securities Act and state law exemptions relating
to offers and sales not by means of a public offering, and that the Company's
reliance on such exemptions is predicated on the undersigned's representations
set forth herein.

       (c) The undersigned agrees that in no event will it make a disposition of
any Securities acquired upon the exercise of the Warrant unless and until (i) it
shall have notified the Company of the proposed disposition and shall have
furnished the Company with a statement of the circumstances surrounding the
proposed disposition, and (ii) it shall have furnished the Company with an
opinion of counsel satisfactory to the Company and Company's counsel to the
effect that (A) appropriate action necessary for compliance with the Securities
Act and any applicable state securities laws has been taken or an exemption from
the registration requirements of the Securities Act and such laws is available,
and (B) the proposed transfer will not violate any of said laws.

       (d) The undersigned acknowledges that an investment in the Company is
highly speculative and represents that it is able to fend for itself in the
transactions contemplated by this statement, has such knowledge and experience
in financial and business matters as to be capable of evaluating the merits and
risks of its investments, and has the ability to bear the economic risks
(including the risk of a total loss) of its investment. The undersigned
represents that it has had the opportunity to ask questions of the Company
concerning the Company's business and assets and to obtain any additional
information which it considered necessary to verify the accuracy of or to
amplify the Company's disclosures, and has had all questions which have been
asked by it satisfactorily answered by the Company.

       (e) The undersigned acknowledges that the Securities issuable upon
exercise or conversion of the Warrant must be held indefinitely unless
subsequently registered under the Securities Act or an exemption from such
registration is available. The undersigned is aware of the provisions of Rule
144 promulgated under the Securities Act which permit limited resale of shares
purchased in a private placement subject to the satisfaction of certain
conditions, including, among other things, the existence of a public market for
the shares, the availability of

                                      -6-
<PAGE>
certain current public information about the Company, the resale occurring not
less than one year after a party has purchased and paid for the security to be
sold from the Company or any affiliate of the Company, the sale being through a
"broker's transaction" or in transactions directly with a "market maker" (as
provided by Rule 144(f)) and the number of shares being sold during any three
month period not exceeding specified limitations.

Dated:
      ----------------------------

----------------------------------
(Typed or Printed Name)


By:
   -------------------------------
            (Signature)

----------------------------------
(Name)


----------------------------------
(Title)


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