<PAGE>

================================================================================
                                 UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, DC 20549

                                  FORM 10-K/A
(Mark one)

[X]  ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 (d) OF THE SECURITIES EXCHANGE
     ACT OF 1934

For the fiscal year ended              December 31, 2000
                               ---------------------------------

                                      OR

[_]  TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 (d) OF THE SECURITIES
     EXCHANGE OF 1934

     For the transition period from  __________  to  _______________

     Commission File Number                   0-15472
                             ----------------------------------------

                        Environmental Power Corporation
            (Exact name of registrant as specified in its charter)

              Delaware                                       04-2782065
   (State or other jurisdiction of                         (IRS Employer
    incorporation or organization)                      Identification No.)

        500 Market Street, Suite 1-E, Portsmouth, New Hampshire  03801
                   (Address of principal executive offices)
                                  (Zip code)

                                (603) 431-1780
              Registrant's telephone number, including area code

          Securities registered pursuant to Section 12(g) of the Act:
                         Common Stock, $.01 par value

Indicate by check mark whether the registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the preceding 12 months (or for such shorter period that the registrant was
required to file such reports), and (2) has been subject to such filing
requirements for the past 90 days.

Yes  [X]    No  [_]

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405
of Regulation S-K is not contained herein, and will not be contained, to the
best of registrant's knowledge, in definitive proxy or information statements
incorporated by reference in Part III of this Form 10-K or any amendment to the
Form 10-K. [X]

State the aggregate market value for the voting stock held by non-affiliates of
the registrant: The aggregate market value, computed by reference to the closing
price of such stock on April 23, 2001, was $2,019,698.

Indicate the number of shares outstanding of each of the registrant's classes of
common stock, as of the last practicable date:  On April 23, 2001 there were
11,406,783 outstanding shares of Common Stock, $.01 par value, of the
registrant.

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                                       1
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                      DOCUMENTS INCORPORATED BY REFERENCE

None

                               TABLE OF CONTENTS

<TABLE>
<CAPTION>
Description of Contents                                                                                 Page #
-----------------------                                                                                 ------

PART III:
---------
<S>                                                                                                     <C>
Item 10.   Directors and Executive Officers                                                                2
Item 11.   Executive Compensation                                                                          4
Item 12.   Security Ownership of Certain Beneficial Owners and Management                                  6
Item 13.   Certain Relationships and Related Transactions                                                  7
Signature page                                                                                             8
</TABLE>

                                    PART III
                                    --------

Item 10.   DIRECTORS AND EXECUTIVE OFFICERS

The Company's directors are elected annually by the shareholders and hold office
for the ensuing year and until their successors have been elected and qualified.
The following table sets forth the ages and principal occupations for the
Company's directors during the past five years.

<TABLE>
<CAPTION>
Name                             Age          Principal Occupation
----                             ---          --------------------
<S>                              <C>          <C>
Joseph E. Cresci                 58           Chairman and Chief Executive Officer of
                                              the Company (1982 to present).

Donald A. Livingston             58           President and Chief Operating Officer of
                                              the Company (1991 to present).

Peter J. Blampied                58           Trustee, Northeast Investors Trust (2000 to present);
                                              President, Corcoran Management Company (1998-present);
                                              Director, A.W. Perry, Inc. (1998 - present);
                                              Director, Access Capital Strategies (1997 - present);
                                              Director, Nellie Mae (1982 - present);  Director,
                                              Citizens Bank of Massachusetts (1996 to 1999); and
                                              Director, Citizens Financial Group, Inc. (1994-1996)

Edward B. Koehler, Esq.          47           Partner, Hunton & Williams, Hong Kong (1990 to present)

Robert I. Weisberg               53           President and Chief Executive Officer, Alco Financial
                                              Services, LLC (1997 - present); Trustee, Monterey
                                              Mutual Fund (1998 to present); and President and Chief
                                              Executive Officer, Pro-Care Financial Group, Inc.
                                              (1994 - 1997)
</TABLE>

                                       2
<PAGE>

Mr. Blampied is a director for Access Capital Strategies, 124 Mount Auburn
Street, Cambridge, MA 02138 and a trustee for Northeast Investors Trust, 50
Congress Street, Boston, MA 02109.  Mr. Weisberg is a trustee for Monterey
Mutual Fund, 1299 Ocean Avenue, Suite 210, Santa Monica, California 90401.
Except as noted herein, none of the Company's directors hold any other
directorships in any company subject to the reporting requirements of the
Securities Exchange Act of 1934 or in any company registered as an investment
company under the Investment Company Act of 1940.

The Company's executive officers, which are elected annually by the Board of
Directors and serve at the discretion of the Board, are as follows:

      Name              Age                Position
      ----              ---                --------
Joseph E. Cresci         58    Chairman and Chief Executive Officer

Donald A. Livingston     58    President and Chief Operating Officer

William D. Linehan       35    Treasurer, Secretary and Chief Financial Officer

Joseph E. Cresci, a founder of the Company, has served as Chairman and Chief
Executive Officer since the Company's inception in 1982, as Treasurer of the
Company from its inception until September 1987 and as President from inception
until September 1991.  From 1976 to 1982, Mr. Cresci was President and Chief
Executive Officer of G.E. Stimpson Co., Inc. and Stimpson Systems, Inc., a
distributor of office and printing products.  From 1972 to 1975, Mr. Cresci was
President of Ogden Recreation, Inc., a subsidiary of Ogden Corp. (NYSE) where he
was responsible for the operation of racing facilities, a hotel/resort, a
parking company and a promotions company providing services to large crowd
facilities.  Mr. Cresci was Executive Vice President and Chief Operating Officer
of Garden State Racing Association from 1969 to 1972.  From 1967 to 1969, he was
an associate lawyer with the Philadelphia law firm of Townsend, Elliott and
Munson.  Mr. Cresci holds a B.A. degree from Princeton University and a law
degree from Cornell Law School and is a member of the Pennsylvania and
Massachusetts Bar Associations.

Donald A. Livingston, a founder of the Company, has served as President and
Chief Operating Officer since September 1991, and as Executive Vice President
from the Company's inception until September 1991. From 1974 to 1982, Mr.
Livingston was President and Chief Executive Officer of Green Mountain
Outfitters, Inc., a manufacturer and distributor of large plastic parts.  During
the three previous years, he was a partner in the financial services firm of
Capital Resources, Inc., where he was involved in obtaining debt and equity
funds, and negotiating mergers and acquisitions.  Mr. Livingston was a
registered representative in the retail stock brokerage business with Baxter,
Blyden and Selheimer from 1967 to 1971 and Bellamah, Neuhauser & Barrett from
1965 to 1967.

William D. Linehan has served as Treasurer, Secretary and Chief Financial
Officer of the Company since March 29, 1996.  Prior to his employment with the
Company, Mr. Linehan was most recently employed since 1993 as manager in the
audit and consulting practice of Moody, Cavanaugh and Company, where he
specialized in providing audit, tax advisory and business consulting services to
closely-held corporations.  From 1991 to 1993, Mr. Linehan was the Controller of
Technology Procurement, Inc. and later the Secretary and Treasurer of Computer
Finance and Rental, Inc., a corporation formed in 1993 after a corporate
reorganization of Technology Procurement, Inc., where he was responsible for
managing the accounting and financial activities of these corporations, which
both were distributors and lessors of computer equipment and related peripheral
products.  From 1987 to 1991, Mr. Linehan was employed in the middle market
audit and consulting practice of KPMG Peat Marwick, where he advanced to the
position of supervisor and specialized in providing audit and management
advisory services to publicly-traded and privately-held growth companies.  Mr.
Linehan, who received a Bachelor of Science Degree in Accountancy from Bentley
College in 1987, is a Certified Public Accountant in the Commonwealth of
Massachusetts and a member of the American Institute of Certified Public
Accountants.

                                       3
<PAGE>

Section 16(a) Beneficial Ownership Reporting Compliance

Section 16(a) of the Securities Exchange Act of 1934, as amended, requires the
Company's officers and Directors, and persons who own more than ten percent of a
registered class of the Company's equity securities, to file initial statements
of beneficial ownership (Form 3), and statements of changes in beneficial
ownership (Forms 4 or 5), of Common Stock and other equity securities of the
Company with the Securities and Exchange Commission (the "SEC").  Officers,
directors and greater than ten percent stockholders are required by SEC
regulation to furnish the Company with copies of all such forms they file.

The Company believes, based solely on its review of the copies of forms received
by it, or written representations from certain reporting persons that no
additional forms were required for those persons, that its officers, directors
and greater than ten-percent beneficial owners complied with all filing
requirements applicable to them for 2000.

Item 11.   EXECUTIVE COMPENSATION

Compensation of Executive Officers

Summary Compensation Table:  The following table sets forth certain information
with respect to the annual and long-term compensation of the Company's Chief
Executive Officer, Chief Operating Officer and each other executive officer
earning in excess of $100,000 in salary and bonus in 2000 (the "Named
Executives") for the three fiscal years ended December 31, 2000.

<TABLE>
<CAPTION>
                                           Annual Compensation                           Long-Term Compensation
                                           -------------------                           ----------------------

Name and                                                                               Restricted
Principal Position                 Year           Salary           Bonus              Stock Awards        Options
------------------                 ----          --------         --------            ------------        -------
<S>                                <C>           <C>              <C>                 <C>                 <C>
Joseph E. Cresci                   2000          $150,000         $350,000                   --             --
Chairman of the Board and          1999           150,000               --                   --             --
Chief Executive Officer            1998            67,584               --                   --             --

Donald A. Livingston               2000          $150,000         $350,000                   --             --
President and                      1999           150,000               --                   --             --
Chief Operating Officer            1998            90,569               --                   --             --

William D. Linehan                 2000          $ 91,708         $ 10,000                   --             --
Secretary, Treasurer and           1999            71,500               --                   --             --
Chief Financial Officer            1998            71,500            7,500                   --             --
</TABLE>

Stock Options:  There were no options granted during 2000 to the Named
Executives.  As of December 31, 2000, there were no unexercised options held by
the Named Executives.

Defined Benefit Pension Plan:  In December 1998, the Company established a
noncontributory defined benefit pension plan (the "Pension Plan") covering all
eligible employees of the Company.  The Pension Plan is subject to the
provisions of the Employee Retirement Income Security Act of 1974.  Employees
aged 21 or older who have completed twelve months of service during which they
worked a minimum of 1,000 hours are eligible to participate.  Employees earn a
year of service for vesting purposes in each employment year in which they
complete at least 1,000 hours of employment. Employees become vested in

                                       4
<PAGE>

the Pension Plan over a 6 year period (20% after 2 years and 20% per year
thereafter, to 100% after 6 years). Benefits are based upon the participant's
annual compensation (including bonuses and similar special pay), as more fully
defined in the Pension Plan, over the number of years of service up to a maximum
of 25 years.

The following table shows the estimated annual pension benefits payable upon
retirement to a participant of the Pension Plan for various salary levels and
years of service.

<TABLE>
<CAPTION>
                Average                                       Years of Service
                                                              ----------------
          Annual Compensation                   10           15             20               25
          -------------------                   --           --             --               --
          <S>                                 <C>          <C>            <C>              <C>
                100,000                       11,000       24,750         44,000           55,000
                150,000                       16,500       37,125         66,000           82,500
                200,000                       18,700       42,075         74,800           93,500
                250,000                       18,700       42,075         74,800           93,500
</TABLE>

During fiscal year 2000, the maximum amount of annual compensation which may be
included for Pension Plan purposes was $170,000. The figures shown above apply
under the Pension Plan as of December 31, 2000.  The benefit amounts listed are
not subject to any deduction for Social Security or other offset amounts. As a
result of limitations imposed under the Federal income tax law, the maximum
annual benefit payable under the Pension Plan for the fiscal year ending
December 31, 2000 is $135,000, although the amount will be actuarially adjusted
in accordance with Federal income tax regulations if payments commence prior to
or following the date that unreduced Social Security benefits become payable. As
of December 31, 2000, Messrs. Cresci and Livingston each had eighteen years of
credited service service under the Pension Plan and Mr. Linehan had five years
of credited service under the Pension Plan.

Compensation of Directors

Each director of the Company who is not an officer or employee of the Company
receives $2,000 (plus expenses) for each scheduled meeting of the Board of
Directors or non-coincident meeting of a board committee which he attends.

During 2000, Messrs. Blampied and Weisberg received option grants to purchase
10,000 shares each under the Company's Director Option Plan which are
exercisable at per share prices of $.50 and $.6875, respectively, based on the
market prices of the Common Stock on their respective anniversary dates of
becoming directors.  Mr. Koehler, under the policies of the law firm in which he
is a partner, which law firm periodically provides services to the Company, is
prohibited from owning shares in the Company.

Compensation Committee Interlocks and Insider Participation

The Compensation Committee is comprised of Peter J. Blampied, Edward B. Koehler
and Robert I. Weisberg. No member of the Compensation Committee is now an
officer or an employee of the Company or any of its subsidiaries or has been at
any time an officer or employee of the Company or any of its subsidiaries.

Mr. Koehler is a partner with Hunton & Williams, Hong Kong, a law firm which
periodically provides services to the Company.

                                       5
<PAGE>

Item 12.     SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT

The following table sets forth as of April 23, 2001 the name of each person who,
to the knowledge of the Company, owned beneficially more than 5% of the shares
of Common Stock of the Company outstanding at such date, the number of shares
owned by each of such persons and the percentage of the class represented
thereby.

<TABLE>
<CAPTION>
         Name and Address of                         Amount and Nature of                       Percentage
           Beneficial Owner                        Beneficial Ownership (1)                      of Class
           ----------------                        ------------------------                      --------
<S>                                                <C>                                          <C>
Joseph E. Cresci                                         4,725,348 (2)(4)                         41.43%
c/o Environmental Power Corporation
500 Market Street, Suite 1-E
Portsmouth, New Hampshire 03801

Donald A. Livingston                                     2,461,739                                21.58%
c/o Environmental Power Corporation
500 Market Street, Suite 1-E
Portsmouth, New Hampshire 03801

James F. Powers, as Trustee                              1,000,000 (3)                             8.77%
c/o Vitale Caturano and Company
210 Commercial Street
Boston, MA 02109
</TABLE>

(1)  Information with respect to beneficial ownership is based upon information
     furnished by such stockholders. Except as indicated in notes 2, 3 and 4 all
     shares are held beneficially and of record.

(2)  Includes 3,665,618 shares held in a revocable trust for the benefit of
     members of Mr. Cresci's family, of which Mr. Cresci is the trustee, and
     59,730 shares held in trust for the benefit of Mr. Cresci and his children,
     as to which Mr. Cresci has shared voting and investment power; but does not
     include 20,000 shares owned by Mr. Cresci's wife, as to which shares Mr.
     Cresci has neither voting nor investment power and as to which shares he
     disclaims beneficial ownership.

(3)  Consists of 1,000,000 shares which Mr. Cresci deposited into a voting trust
     (the "Voting Trust") on November 20, 1996 and in which Mr. Powers has
     beneficial ownership in his capacity as trustee with sole voting power.
     Mr. Cresci also has beneficial ownership in such shares which are evidenced
     by voting trust certificates held by The Cresci Family Limited Partnership
     of which Mr. Cresci is the sole general partner with sole dispositive
     power.

(4)  Includes 1,000,000 shares held by the Voting Trust (See Note 3).


The following table sets forth as of April 23, 2001 the number and percentage of
outstanding shares of Common Stock beneficially owned by the Company's Named
Executives, Directors, and Directors and Officers as a group. Mr. Linehan, a
Named Executive, and Mr. Koehler, a Director, do not beneficially own Common
Stock.

                                       6
<PAGE>

<TABLE>
<CAPTION>
    Nominee's Name                     Positions and                   Amount & Nature
    and Date First                     Offices with                     of Beneficial        Percent of
  Became a Director                     the Company                     Ownership (1)           Class
  -----------------                     -----------                     -------------        ----------
<S>                          <C>                                    <C>                     <C>
Joseph E. Cresci             Chairman, Chief Executive                    4,725,348 (2)         41.43%
1982                         Officer and Director

Donald A. Livingston         President, Chief Operating
1982                         Officer and Director                         2,461,739             21.58%


Peter J. Blampied            Director                                       130,300 (3)          1.14%
1988

Robert I. Weisberg           Director                                       110,000 (4)           .96%
1994

All Directors and Officers as a group (6 persons)                         7,427,387 (5)         64.77%
</TABLE>

(1)  Except as otherwise indicated, the named person has sole voting and
     investment power with respect to the shares. Except as indicated in notes
     2, 3, and 4, all shares are held beneficially and of record.

(2)  Includes 3,665,618 shares held in a revocable trust for the benefit of
     members of Mr. Cresci's family, of which Mr. Cresci is the trustee, and
     1,000,000 shares held by the Voting Trust and 59,730 shares held in trust
     for the benefit of Mr. Cresci and his children; but does not include 20,000
     shares owned by Mr. Cresci's wife as to which shares he disclaims
     beneficial ownership. Mr. Cresci has shared voting and investment power
     with respect to the 59,730 shares held in trust for the benefit of himself
     and his children but no voting power with respect to the shares held in the
     Voting Trust.

(3)  Includes 30,000 shares which Mr. Blampied has the right to acquire pursuant
     to stock options which are all currently exercisable.

(4)  Includes 30,000 shares which Mr. Weisberg has the right to acquire pursuant
     to stock options which are all currently exercisable.

(5)  Includes 60,000 shares which Messrs. Blampied and Weisberg have the right
     to acquire pursuant to stock options which are all currently exercisable.

Item 13.     CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS

In December 1985, the Company loaned $55,000 to Mr. Livingston. This loan
incurred interest at a bank's floating prime rate plus 1/2% and was due and
payable by December 31, 2000. On December 29, 2000, Mr. Livingston made
aggregate principal and interest payments of $128,218 to satisfy this
obligation.

During 1993 and 1995, Messrs. Cresci and Livingston exercised options to
purchase shares of the Company's Common Stock.  As payment for the exercise
price of these stock options, the Company accepted promissory notes which are
payable upon demand by the Company from Messrs. Cresci and Livingston
aggregating $332,875 and $428,281, respectively.  Interest on these notes, which
is payable monthly at the Applicable Federal Rate, amounted to $46,735 in the
aggregate during 2000 and has been fully collected from Messrs.

                                       7
<PAGE>

Cresci and Livingston. As of April 23, 2001, Messrs. Cresci and Livingston had
aggregate balances due to the Company of $186,875 and $410,498, respectively
under the these notes.

In September 1997, Mr. Weisberg exercised options to purchase 80,000 shares of
the Company's Common Stock.  As payment for the exercise price of these stock
options, the Company accepted a promissory note which is payable upon demand by
the Company from Mr. Weisberg in the amount of $48,575.  Interest on this note,
which is payable quarterly at the Applicable Federal Rate, amounted to $2,983 in
2000 and has been fully collected from Mr. Weisberg.

Edward B. Koehler is a partner with Hunton & Williams, Hong Kong, a law firm
which periodically provides services to the Company.

                                   SIGNATURES

Pursuant to the requirements of Section 13 or 15 (d) of the Securities Exchange
Act of 1934, the registrant has duly caused this report to be signed on its
behalf by the undersigned, thereunto duly authorized.

Dated:                     ENVIRONMENTAL POWER CORPORATION

April 26, 2001        By   /s/ William D. Linehan
                           -----------------------------------------------------
                           Treasurer, Secretary and Chief Financial Officer
                           (principal accounting officer and authorized officer)

                                       8