SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549
                                ----------------

                                 SCHEDULE 13G/A
                                ----------------


             INFORMATION STATEMENT PURSUANT TO RULES 13d-1 AND 13d-2
                    UNDER THE SECURITIES EXCHANGE ACT OF 1934

                                 Amendment No. 2

                         Environmental Power Corporation
                                (NAME OF ISSUER)

                     Common Stock, par value $0.01 per share
                         (TITLE OF CLASS OF SECURITIES)

                                    29406L201
                                 (CUSIP NUMBER)

                                December 31,2009
             (Date of Event which requires Filing of this Statement)

        Check the appropriate box to designate the rule pursuant to which
                             this Schedule is filed:

                                [ ] Rule 13d-1(b)
                                [x] Rule 13d-1(c)
                                [ ] Rule 13d-1(d)






                              (Page 1 of 14 Pages)
------------------

* The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter the
disclosures provided in a prior cover page.

     The information required in the remainder of this cover page shall not be
deemed to be "filed" for the purpose of Section 18 of the Securities Exchange
Act of 1934 ("Act") or otherwise subject to the liabilities of that section of
the Act but shall be subject to all other provisions of the Act (however, see
the Notes).





CUSIP No. 29406L201                     13G/A                PAGE 2 of 14 PAGES

------------------------------------------------------------------------------
     (1)    NAME OF REPORTING PERSON
            S.S. OR I.R.S. IDENTIFICATION NO.
            OF ABOVE PERSON
            Ardsley Partners Renewable Energy Fund, L.P.
------------------------------------------------------------------------------
     (2)    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP **
                                                                    (a)  [x]
                                                                    (b)  [ ]
------------------------------------------------------------------------------
     (3)    SEC USE ONLY

------------------------------------------------------------------------------
     (4)    CITIZENSHIP OR PLACE OF ORGANIZATION
            Delaware
------------------------------------------------------------------------------

NUMBER OF      (5)  SOLE VOTING POWER
                    0
SHARES
------------------------------------------------------------------------------
BENEFICIALLY   (6)  SHARED VOTING POWER
                    310,000
OWNED BY
------------------------------------------------------------------------------

EACH           (7)  SOLE DISPOSITIVE POWER
                    0
REPORTING
------------------------------------------------------------------------------

PERSON WITH    (8)  SHARED DISPOSITIVE POWER
                    310,000
------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED
            BY EACH REPORTING PERSON
            310,000
------------------------------------------------------------------------------
    (10)    CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES **                          [ ]
------------------------------------------------------------------------------
    (11)    PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
            1.97%
------------------------------------------------------------------------------
     (12)   TYPE OF OF REPORTING PERSON **
               PN
------------------------------------------------------------------------------
             ** SEE INSTRUCTIONS BEFORE FILLING OUT!





CUSIP No. 29406L201                     13G/A                PAGE 3 of 14 PAGES

------------------------------------------------------------------------------
     (1)    NAME OF REPORTING PERSON
            S.S. OR I.R.S. IDENTIFICATION NO.
            OF ABOVE PERSON
            Ardsley Renewable Energy Offshore Fund, Ltd.
------------------------------------------------------------------------------
     (2)    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP **
                                                                    (a)  [x]
                                                                    (b)  [ ]
------------------------------------------------------------------------------
     (3)    SEC USE ONLY

------------------------------------------------------------------------------
     (4)    CITIZENSHIP OR PLACE OF ORGANIZATION
            British Virgin Islands
------------------------------------------------------------------------------

NUMBER OF      (5)  SOLE VOTING POWER
                    0
SHARES
------------------------------------------------------------------------------

BENEFICIALLY   (6)  SHARED VOTING POWER
                    140,000
OWNED BY
------------------------------------------------------------------------------

EACH           (7)  SOLE DISPOSITIVE POWER
                    0
REPORTING
------------------------------------------------------------------------------

PERSON WITH    (8)  SHARED DISPOSITIVE POWER
                    140,000
------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED
            BY EACH REPORTING PERSON
            140,000
------------------------------------------------------------------------------
    (10)    CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES **                          [ ]
------------------------------------------------------------------------------
    (11)    PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
            0.89%
------------------------------------------------------------------------------
     (12)   TYPE OF OF REPORTING PERSON **
               CO
------------------------------------------------------------------------------
             ** SEE INSTRUCTIONS BEFORE FILLING OUT!





CUSIP No. 29406L201                     13G/A                PAGE 4 of 14 PAGES

------------------------------------------------------------------------------
     (1)    NAME OF REPORTING PERSON
            S.S. OR I.R.S. IDENTIFICATION NO.
            OF ABOVE PERSON
            Ardsley Advisory Partners
------------------------------------------------------------------------------
     (2)    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP **
                                                                    (a)  [x]
                                                                    (b)  [ ]
------------------------------------------------------------------------------
     (3)    SEC USE ONLY

------------------------------------------------------------------------------
     (4)    CITIZENSHIP OR PLACE OF ORGANIZATION
            Connecticut
------------------------------------------------------------------------------

NUMBER OF      (5)  SOLE VOTING POWER
                    0
SHARES
------------------------------------------------------------------------------

BENEFICIALLY   (6)  SHARED VOTING POWER
                    450,000
OWNED BY
------------------------------------------------------------------------------

EACH           (7)  SOLE DISPOSITIVE POWER
                    0
REPORTING
------------------------------------------------------------------------------

PERSON WITH    (8)  SHARED DISPOSITIVE POWER
                    450,000
------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED
            BY EACH REPORTING PERSON
            450,000
------------------------------------------------------------------------------
    (10)    CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES **                          [ ]
------------------------------------------------------------------------------
    (11)    PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
            2.86%
------------------------------------------------------------------------------
    (12)    TYPE OF REPORTING PERSON **
               PN; IA
------------------------------------------------------------------------------
             ** SEE INSTRUCTIONS BEFORE FILLING OUT!





CUSIP No. 29406L201                     13G/A                PAGE 5 of 14 PAGES

------------------------------------------------------------------------------
     (1)    NAME OF REPORTING PERSON
            S.S. OR I.R.S. IDENTIFICATION NO.
            OF ABOVE PERSON
            Ardsley Partners I
------------------------------------------------------------------------------
     (2)    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP **
                                                                    (a)  [x]
                                                                    (b)  [ ]
------------------------------------------------------------------------------
     (3)    SEC USE ONLY

------------------------------------------------------------------------------
     (4)    CITIZENSHIP OR PLACE OF ORGANIZATION
            Connecticut
------------------------------------------------------------------------------

NUMBER OF      (5)  SOLE VOTING POWER
                    0
SHARES
------------------------------------------------------------------------------

BENEFICIALLY   (6)  SHARED VOTING POWER
                    310,000
OWNED BY
------------------------------------------------------------------------------

EACH           (7)  SOLE DISPOSITIVE POWER
                    0
REPORTING
------------------------------------------------------------------------------

PERSON WITH    (8)  SHARED DISPOSITIVE POWER
                    310,000
------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED
            BY EACH REPORTING PERSON
            310,000
------------------------------------------------------------------------------
    (10)    CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES **                          [ ]
------------------------------------------------------------------------------
    (11)    PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
            1.97%
------------------------------------------------------------------------------
     (12)   TYPE OF OF REPORTING PERSON **
               PN
------------------------------------------------------------------------------
             ** SEE INSTRUCTIONS BEFORE FILLING OUT!





CUSIP No. 29406L201                      13G/A               PAGE 6 of 14 PAGES

------------------------------------------------------------------------------
     (1)    NAME OF REPORTING PERSON
            S.S. OR I.R.S. IDENTIFICATION NO.
            OF ABOVE PERSON
            Philip J. Hempleman
------------------------------------------------------------------------------
     (2)    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP **
                                                                    (a)  [x]
                                                                    (b)  [ ]
------------------------------------------------------------------------------
     (3)    SEC USE ONLY

------------------------------------------------------------------------------
     (4)    CITIZENSHIP OR PLACE OF ORGANIZATION
            United States
------------------------------------------------------------------------------

NUMBER OF      (5)  SOLE VOTING POWER
                    0
SHARES
------------------------------------------------------------------------------

BENEFICIALLY   (6)  SHARED VOTING POWER
                    450,000
OWNED BY
------------------------------------------------------------------------------

EACH           (7)  SOLE DISPOSITIVE POWER
                    0
REPORTING
------------------------------------------------------------------------------

PERSON WITH    (8)  SHARED DISPOSITIVE POWER
                    450,000
------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED
            BY EACH REPORTING PERSON
            450,000
------------------------------------------------------------------------------
    (10)    CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES **                          [ ]
------------------------------------------------------------------------------
    (11)    PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
            2.86%
------------------------------------------------------------------------------
     (12)   TYPE OF OF REPORTING PERSON **
               IN
------------------------------------------------------------------------------
             ** SEE INSTRUCTIONS BEFORE FILLING OUT!





CUSIP No. 29406L201                      13G/A               PAGE 7 of 14 PAGES

ITEM 1(a).  NAME OF ISSUER:

            The name of the  issuer  is  Environmental  Power  Corporation  (the
"Company").

ITEM 1(b).  ADDRESS OF ISSUER'S PRINCIPAL EXECUTIVE OFFICES:
            120 White Plains Road, 6th Floor, Tarrytown, NY 10591.

ITEM 2(a).  NAME OF PERSON FILING:

      This statement is filed by:

      (i)    Ardsley  Partners  Renewable  Energy Fund, L.P., a Delaware limited
             partnership  ("Ardsley  Energy"),  with  respect  to the  shares of
             Common Stock,  par value $0.01 per share ("Common  Stock") directly
             owned by it;

      (ii)   Ardsley  Renewable  Energy  Offshore  Fund,  Ltd., a British Virgin
             Islands  corporation  ("Ardsley Energy Offshore"),  with respect to
             the shares of Common Stock directly owned by it;

      (iii)  Ardsley  Advisory   Partners,   a  New  York  general   partnership
             ("Ardsley")  which serves as Investment  Manager of Ardsley  Energy
             Offshore and the  Investment  Adviser of Ardsley Energy and certain
             managed  accounts,  with  respect  to the  shares of  Common  Stock
             directly owned by Ardsley Energy  Offshore,  Ardsley Energy and the
             managed accounts;

      (iv)   Ardsley  Partners  I,  a New  York  general  partnership  ("Ardsley
             Partners") which serves as General Partner of Ardsley Energy; and

      (v)    Philip J. Hempleman  ("Mr.  Hempleman"),  the Managing  Partner of'
             Ardsley and Ardsley Partners,  with respect to the shares of Common
             Stock owned by Ardsley  Energy,  Ardsley  Energy  Offshore  and the
             managed accounts.

            The foregoing persons are hereinafter sometimes collectively
referred to as the "Reporting Persons." Any disclosures herein with respect to
persons other than the Reporting Persons are made on information and belief
after making inquiry to the appropriate party.

ITEM 2(b).  ADDRESS OF PRINCIPAL OFFICE OR, IF NONE, RESIDENCE:

     The address of the business office of each of the Reporting Persons, with
the exception of Ardsley Energy Offshore, is 262 Harbor Drive, Stamford,
Connecticut 06902.

     The address of the registered office of Ardsley Energy Offshore is Romasco
Place, Wickhams Cay 1, Roadtown Tortola, British Virgin Islands.





CUSIP No. 29406L201                      13G/A               PAGE 8 of 14 PAGES

ITEM 2(c).  CITIZENSHIP:

     Ardsley Energy is a Delaware limited partnership. Ardsley Energy Offshore
is British Virgin Islands corporation. Ardsley and Ardsley Partners are New York
general partnerships. Mr. Hempleman is a United States Citizen.

ITEM 2(d).  TITLE OF CLASS OF SECURITIES: Class A Common Stock, par value
$0.01 per share

ITEM 2(e).  CUSIP NUMBER:  29406L201

ITEM 3. IF THIS STATEMENT IS FILED PURSUANT TO RULES 13d-1(b), OR 13d-2(b),
CHECK WHETHER THE PERSON FILING IS A:

          (a) [ ]  Broker or dealer registered under Section 15 of the Act

          (b) [ ]  Bank as defined in Section 3(a)(6) of the Act

          (c) [ ]  Insurance Company as defined in Section 3(a)(19) of the Act

          (d) [ ]  Investment Company registered under Section 8 of the
                   Investment Company Act

          (e) [ ]  Investment Adviser registered under Section 203 of the
                   Investment Advisers Act of 1940

          (f) [ ]  Employee Benefit Plan, Pension Fund which is subject to
                   the provisions of the Employee Retirement Income Security
                   Act of 1974 or Endowment Fund; see Rule 13d- 1(b)(1)(ii)(F)

          (g) [ ]  Parent Holding Company, in accordance with Rule 13d-
                   1(b)(ii)(G); see item 7

          (h) ( )  Group, in accordance with Rule 13d-1(b)(1)(ii)(H)

If this statement is filed pursuant to Rule 13d-1(c), check the box. [X]





CUSIP No. 29406L201                     13G/A                PAGE 9 of 14 PAGES

ITEM 4.   OWNERSHIP.

      A.    Ardsley Partners Renewable Energy Fund, L.P.
            (a) Amount beneficially owned: 310,000
            (b)   Percent of class: 1.97% (The percentages used herein and in
                  the rest of Item 4 are calculated based upon 15,708,591 shares
                  of Common Stock issued and outstanding as of September 30,
                  2009 as reported in the Company's 10-Q as filed with the
                  Securities and Exchange Commission on November 9, 2009)
            (c)   (i)   Sole Power to vote or direct the vote: -0-
                  (ii)  Shared power to vote or direct the vote: 310,000
                  (iii) Sole power to dispose or direct the disposition: -0-
                  (iv)  Shared power to dispose or direct the disposition:
                        310,000

      B.    Ardsley Renewable Energy Offshore Fund, Ltd.
            (a) Amount beneficially owned: 140,000
            (b) Percent of class: 0.89%
            (c)   (i)   Sole Power to vote or direct the vote: -0-
                  (ii)  Shared power to vote or direct the vote: 140,000
                  (iii) Sole power to dispose or direct the disposition: -0-
                  (iv)  Shared power to dispose or direct the disposition:
                        140,000

      C.    Ardsley Advisory Partners
            (a) Amount beneficially owned: 450,000
            (b) Percent of class: 2.86%
            (c)   (i)   Sole Power to vote or direct the vote: -0-
                  (ii)  Shared power to vote or direct the vote: 450,000
                  (iii) Sole power to dispose or direct the disposition: -0-
                  (iv)  Shared power to dispose or direct the disposition:
                        450,000

      D. Ardsley Partners I
            (a) Amount beneficially owned: 310,000
            (b) Percent of class: 1.97%
            (c)   (i)   Sole Power to vote or direct the vote: -0-
                  (ii)  Shared power to vote or direct the vote: 310,000
                  (iii) Sole power to dispose or direct the disposition: -0-
                  (iv)  Shared power to dispose or direct the disposition:
                        310,000

      E. Philip J. Hempleman
            (a) Amount beneficially owned: 450,000
            (b) Percent of class: 2.86%
            (c)   (i)   Sole Power to vote or direct the vote: -0-
                  (ii)  Shared power to vote or direct the vote: 450,000
                  (iii) Sole power to dispose or direct the disposition: -0-
                  (iv)  Shared power to dispose or direct the disposition:
                        450,000





CUSIP No. 29406L201                     13G/A                PAGE 10 of 14 PAGES

ITEM 5.   OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS.

          If this  statement  is being  filed to report  the fact that as of the
date hereof the reporting  person has ceased to be the beneficial  owner of more
than five percent of the class of securities, check the following |X|.

ITEM 6.   OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON.
          Not applicable.

ITEM 7.   IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED THE
          SECURITY BEING REPORTED ON BY THE PARENT HOLDING COMPANY.
          Not applicable.

ITEM 8.   IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP.
          Not applicable.

ITEM 9.   NOTICE OF DISSOLUTION OF GROUP.
          Not applicable.

ITEM 10.  CERTIFICATION.

     Each of the Reporting Persons hereby makes the following certification:

          By signing  below I certify,  to the best of my knowledge  and belief,
the  securities  referred  to above  were  acquired  in the  ordinary  course of
business,  were not  acquired  for the  purpose of and do not have the effect of
changing or  influencing  the control of the issuer of such  securities and were
not acquired in connection  with or as a participant in any  transaction  having
such purposes or effect.





CUSIP No. 29406L201                     13G/A                PAGE 11 of 14 PAGES

                                    SIGNATURE

            After reasonable inquiry and to the best of their knowledge and
belief, the undersigned certify that the information set forth in this statement
is true, complete and correct.


DATED: as of February 16, 2010



                              ARDSLEY PARTNERS RENEWABLE ENERGY FUND, L.P.
                              BY:  ARDSLEY PARTNERS I,
                                   GENERAL PARTNER


                               BY:/s/ Steve Napoli
                                  ----------------
                                  Steve Napoli
                                  General Partner


                              ARDSLEY RENEWABLE ENERGY OFFSHORE FUND, LTD.


                               BY:/s/ Steve Napoli
                                  ----------------
                                  Steve Napoli
                                  Director



                              ARDSLEY ADVISORY PARTNERS
                             By: ARDSLEY PARTNERS I
                                 GENERAL PARTNER


                               BY:/s/ Steve Napoli
                                  ----------------
                                  Steve Napoli
                                  General Partner



                               ARDSLEY PARTNERS I

                               BY:/s/ Steve Napoli
                                  ----------------
                                  Steve Napoli
                                  General Partner





CUSIP No. 29406L201                     13G/A                PAGE 12 of 14 PAGES


                              PHILIP J. HEMPLEMAN, INDIVIDUALLY


                              BY:/s/ Steve Napoli*
                                 -----------------
                                    Steve Napoli
                               As attorney in fact for
                               Philip J. Hempleman


*  Evidence of Power of Attorney was filed with the Schedule 13G/A filed on
   February 15, 2006 (Acc-no: 0000902664-06-000895) and is incorporated by
   reference into this filing.





CUSIP No. 29406L201                     13G/A                PAGE 13 of 14 PAGES


                                    EXHIBIT 1
               JOINT FILING AGREEMENT PURSUANT TO RULE 13d-1(k)(1)

            The undersigned  acknowledge and agree that the foregoing  statement
on  Schedule  13G/A is filed on behalf of each of the  undersigned  and that all
subsequent  amendments to this statement shall be filed on behalf of each of the
undersigned  without the necessity of filing additional joint filing statements.
The undersigned acknowledge that each shall be responsible for the timely filing
of such  amendments,  and for the  completeness  and accuracy of the information
concerning him, her or it contained herein, but shall not be responsible for the
completeness  and accuracy of the  information  concerning the other entities or
persons,  except to the extent that he, she or it knows or has reason to believe
that such information is inaccurate.

Dated as of February 16, 2010



                              ARDSLEY PARTNERS RENEWABLE ENERGY FUND, L.P.
                              BY:  ARDSLEY PARTNERS I,
                                   GENERAL PARTNER


                               BY:/s/ Steve Napoli
                                  ----------------
                                  Steve Napoli
                                  General Partner


                              ARDSLEY RENEWABLE ENERGY OFFSHORE FUND, LTD.


                               BY:/s/ Steve Napoli
                                  ----------------
                                  Steve Napoli
                                  Director



                              ARDSLEY ADVISORY PARTNERS

                             By: ARDSLEY PARTNERS I
                                 GENERAL PARTNER

                               BY:/s/ Steve Napoli
                                  ----------------
                                  Steve Napoli
                                  General Partner





CUSIP No. 29406L201                     13G/A                PAGE 14 of 14 PAGES

                               ARDSLEY PARTNERS I

                               BY:/s/ Steve Napoli
                                  ----------------
                                  Steve Napoli
                                  General Partner


                              PHILIP J. HEMPLEMAN, INDIVIDUALLY


                              BY:/s/ Steve Napoli *
                                 ------------------
                                  Steve Napoli
                                  Attorney-in-fact
                                  for Philip J. Hempleman





*  Evidence  of Power of  Attorney  was filed with the  Schedule  13G/A filed on
   February  15, 2006  (Acc-no:  0000902664-06-000895)  and is  incorporated  by
   reference into this filing.