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. 1

                         Environmental Power Corporation
                                (NAME OF ISSUER)

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

                                    29406L201
                                 (CUSIP NUMBER)

                                December 31,2008
             (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
                    443,900
OWNED BY       -----------------------------------------------------------------

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

PERSON WITH    (8)  SHARED DISPOSITIVE POWER
                    443,900
--------------------------------------------------------------------------------
     (9)  AGGREGATE AMOUNT BENEFICIALLY OWNED
          BY EACH REPORTING PERSON
          443,900
--------------------------------------------------------------------------------
    (10)  CHECK BOX IF THE AGGREGATE AMOUNT
          IN ROW (9) EXCLUDES CERTAIN SHARES **                          [ ]
--------------------------------------------------------------------------------
    (11)  PERCENT OF CLASS REPRESENTED
          BY AMOUNT IN ROW (9)
          2.84%
--------------------------------------------------------------------------------
    (12)  TYPE 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
                    430,389
OWNED BY       -----------------------------------------------------------------

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

PERSON WITH    (8)  SHARED DISPOSITIVE POWER
                    430,389
--------------------------------------------------------------------------------
     (9)  AGGREGATE AMOUNT BENEFICIALLY OWNED
          BY EACH REPORTING PERSON
          430,389
--------------------------------------------------------------------------------
    (10)  CHECK BOX IF THE AGGREGATE AMOUNT
          IN ROW (9) EXCLUDES CERTAIN SHARES **                          [ ]
--------------------------------------------------------------------------------
    (11)  PERCENT OF CLASS REPRESENTED
          BY AMOUNT IN ROW (9)
          2.75%
--------------------------------------------------------------------------------
    (12)  TYPE 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
                    874,289
OWNED BY       -----------------------------------------------------------------

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

PERSON WITH    (8)  SHARED DISPOSITIVE POWER
                    874,289
--------------------------------------------------------------------------------
     (9)  AGGREGATE AMOUNT BENEFICIALLY OWNED
          BY EACH REPORTING PERSON
          874,289
--------------------------------------------------------------------------------
    (10)  CHECK BOX IF THE AGGREGATE AMOUNT
          IN ROW (9) EXCLUDES CERTAIN SHARES **                          [ ]
--------------------------------------------------------------------------------
    (11)  PERCENT OF CLASS REPRESENTED
          BY AMOUNT IN ROW (9)
          5.60%
--------------------------------------------------------------------------------
    (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
                    443,900
OWNED BY       -----------------------------------------------------------------

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

PERSON WITH    (8)  SHARED DISPOSITIVE POWER
                    443,900
--------------------------------------------------------------------------------
     (9)  AGGREGATE AMOUNT BENEFICIALLY OWNED
          BY EACH REPORTING PERSON
          443,900
--------------------------------------------------------------------------------
    (10)  CHECK BOX IF THE AGGREGATE AMOUNT
          IN ROW (9) EXCLUDES CERTAIN SHARES **                          [ ]
--------------------------------------------------------------------------------
    (11)  PERCENT OF CLASS REPRESENTED
          BY AMOUNT IN ROW (9)
          2.84%
--------------------------------------------------------------------------------
    (12)  TYPE 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
                    1,074,289
OWNED BY       -----------------------------------------------------------------

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

PERSON WITH    (8)  SHARED DISPOSITIVE POWER
                    1,074,289
--------------------------------------------------------------------------------
     (9)  AGGREGATE AMOUNT BENEFICIALLY OWNED
          BY EACH REPORTING PERSON
                  1,074,289
--------------------------------------------------------------------------------
    (10)  CHECK BOX IF THE AGGREGATE AMOUNT
          IN ROW (9) EXCLUDES CERTAIN SHARES **                          [ ]
--------------------------------------------------------------------------------
    (11)  PERCENT OF CLASS REPRESENTED
          BY AMOUNT IN ROW (9)
          6.88%
--------------------------------------------------------------------------------
    (12)  TYPE 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:
                  One Cate Street 4th Floor, Portsmouth, New Hampshire 03801

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;
         (v)      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;
         (vi)     Ardsley Partners I, a New York general partnership ("Ardsley
                  Partners") which serves as General Partner of Ardsley Energy;
                  and
         (vii)    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 and with respect to the shares of
                  Common Stock owned by certain managed accounts managed by him
                  directly.

                  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: 443,900
                (b)     Percent of class: 2.84% (The percentages used herein and
                        in the rest of Item 4 are calculated based upon
                        15,624,104 shares of Common Stock issued and outstanding
                        as of September 30, 2008 as reported in the Company's
                        10-Q as filed with the Securities and Exchange
                        Commission on November 10, 2008)
                (c)     (i)   Sole Power to vote or direct the vote: -0-
                        (ii)  Shared power to vote or direct the vote: 443,900
                        (iii) Sole power to dispose or direct the disposition:
                              -0-
                        (iv)  Shared power to dispose or direct the disposition:
                              443,900

         B.     Ardsley Renewable Energy Offshore Fund, Ltd.
                (a) Amount beneficially owned: 430,389
                (b) Percent of class: 2.75%
                (c)     (i)   Sole Power to vote or direct the vote: -0-
                        (ii)  Shared power to vote or direct the vote: 430,389
                        (iii) Sole power to dispose or direct the disposition:
                              -0-
                        (iv)  Shared power to dispose or direct the disposition:
                              430,389

         C.     Ardsley Advisory Partners
                (a) Amount beneficially owned: 874,289
                (b) Percent of class: 5.60%
                (c)     (i)   Sole Power to vote or direct the vote: -0-
                        (ii)  Shared power to vote or direct the vote: 874,289
                        (iii) Sole power to dispose or direct the disposition:
                              -0-
                        (iv)  Shared power to dispose or direct the disposition:
                              874,289

         D.     Ardsley Partners I
                (a) Amount beneficially owned: 443,900
                (b) Percent of class: 2.84%
                (c)     (i)   Sole Power to vote or direct the vote: -0-
                        (ii)  Shared power to vote or direct the vote: 443,900
                        (iii) Sole power to dispose or direct the disposition:
                              -0-
                        (iv)  Shared power to dispose or direct the disposition:
                              443,900

         E.     Philip J. Hempleman
                (a) Amount beneficially owned: 1,074,289
                (b) Percent of class: 6.88%
                (c)     (i)   Sole Power to vote or direct the vote: -0-
                        (ii)  Shared power to vote or direct the vote: 1,074,289
                        (iii) Sole power to dispose or direct the disposition:
                              -0-
                        (iv)  Shared power to dispose or direct the disposition:
                              1,074,289




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

ITEM 5.   OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS.
          Not applicable.

ITEM 6.   OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON.
          Ardsley, the Investment Manager of Ardsley Energy Offshore and the
Investment Adviser of certain managed accounts, has the power to vote and direct
the disposition of the proceeds from the sale of the shares of Common Stock
owned by Ardsley Energy Offshore and the managed accounts, and accordingly may
be deemed the direct "beneficial owner" of such shares of Common Stock.

          Ardsley, the Investment Adviser of Ardsley Energy, shares the power to
vote and direct the disposition of the proceeds from the sale of the shares of
Common Stock owned by Ardsley Energy, and, accordingly, may be deemed the direct
"beneficial owner" of such shares of Common Stock.

          Ardsley Partners, the General Partner of Ardsley Energy, shares the
power to vote and direct the disposition of the shares of Common Stock owned by
Ardsley Energy, and, accordingly, may be deemed the direct "beneficial owner" of
such shares of Common Stock.

          Mr. Hempleman is the Managing Partner of Ardsley and Ardsley Partners
and in that capacity directs their operations and therefore may be deemed to be
the indirect "beneficial owner" of the shares of Common Stock owned by Ardsley
Energy Offshore, Ardsley Energy and the managed accounts. Mr. Hempleman
disclaims beneficial ownership of all of the Shares of Common Stock reported in
this 13G/A

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 13, 2009



                                    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 13, 2009



                                    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.