<PAGE>

   As filed with the Securities and Exchange Commission on November 3, 1999

                                   Registration Statement No. 333-______________
================================================================================

                      SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C. 20549

                            ----------------------

                                   FORM S-8
                            REGISTRATION STATEMENT
                                     UNDER
                          THE SECURITIES ACT OF 1933

                            ----------------------

                                PLUG POWER INC.
            (Exact name of Registrant as Specified in Its Charter)

          Delaware                                     22-3672377
  (State of Incorporation)                (I.R.S. Employer Identification No.)

                            968 Albany-Shaker Road
                               Latham, NY 12110
                                (518) 782-7700
  (Address, including zip code, and telephone number, including area code, of
                   Registrant's principal executive offices)

                  Plug Power Inc. 1997 Membership Option Plan
             Plug Power Inc. 1999 Stock Option and Incentive Plan
                           (Full Title of the Plan)
                           ------------------------

                                Gary Mittleman
                     President and Chief Executive Officer
                                Plug Power Inc.
                            968 Albany-Shaker Road
                               Latham, NY 12110
                                (518) 782-7700

(Name, address, including zip code, and telephone number, including area code,
                             of agent for service)

                            ----------------------

                                With a copy to:

                          Robert P. Whalen, Jr., P.C.
                         Goodwin, Procter & Hoar LLP
                                Exchange Place
                       Boston, Massachusetts 02109-2881
                                (617) 570-1000

                            -----------------------


<TABLE>
<CAPTION>
                                                  CALCULATION OF REGISTRATION FEE
==================================================================================================================================
Title of Securities Being Registered    Amounts to be         Proposed Maximum             Proposed Maximum          Amount of
                                        Registered (1)  Offering Price Per Share (2)   Aggregate Offering Price   Registration Fee
----------------------------------------------------------------------------------------------------------------------------------
<S>                                     <C>             <C>                            <C>                        <C>
Common Stock, par value $.01 per           1,434,350             $ 1.00 (2)                   $ 1,434,350               $   399
           share                             579,189             $ 5.00 (2)                   $ 2,895,945               $   805
                                             587,700             $ 6.67 (2)                   $ 3,919,959               $ 1,090
                                             726,900             $11.00 (2)                   $ 7,995,900               $ 2,223
                                           2,343,052             $15.88 (3)                   $37,207,666               $10,344
                                        ------------                                                                    -------

                                           5,671,191 (total)                                                            $14,861
==================================================================================================================================
</TABLE>

(1)  This Registration Statement also relates to such indeterminate number of
     additional shares of Plug Power Inc. Common Stock as may be required
     pursuant to the 1997 Membership Option Plan and the 1999 Stock Option and
     Incentive Plan in the event of a stock dividend, reverse stock split,
     split-up, recapitalization, forfeiture of stock under the plan or other
     similar event.

(2)  Determined pursuant to Rule 457(h) under the  under the Securities Act of
     1933, as amended (the "Securities Act").

(3)  This estimate is made pursuant to Rule 457(c) and (h) of the Securities Act
     solely for the purposes of determining the amount of the registration fee.
     The registration fee is based upon the average of the high and low prices
     for the Registrant's Common Stock, par value $0.01 per share, as reported
     on The Nasdaq National Market on November 1, 1999.

================================================================================
<PAGE>

                                    PART I

             INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS


Item 1.   Plan Information.*
          ----------------


Item 2.   Registrant Information and Employee Plan Annual Information.*
          -----------------------------------------------------------


     * Information required by Part I to be contained in the Section 10(a)
Prospectuses is omitted from this Registration Statement in accordance with Rule
428 under the Securities Act of 1933 (the "Securities Act") and the Introductory
Note to Part I of Form S-8.


                                    PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT


Item 3.   Incorporation of Certain Documents by Reference.
          -----------------------------------------------

     Plug Power Inc. (the "Registrant") hereby incorporates by reference:

     the description of the Registrant's Common Stock contained in the
     Registration Statement on Form 8-A (Registration Statement No. 333-86089),
     dated October 1, 1999, as filed with the Securities and Exchange Commission
     on October 1, 1999 pursuant to Section 12(g) of the Securities Exchange Act
     of 1934, as amended.

     In addition, all documents subsequently filed with the Securities and
Exchange Commission by the Registrant pursuant to Sections 13(a), 13(c), 14 and
15(d) of the Exchange Act, prior to the filing of a post-effective amendment
hereto that indicates that all securities offered hereunder have been sold or
which deregisters all securities then remaining unsold, shall be deemed to be
incorporated by reference in this Registration Statement and to be a part hereof
from the date of filing of such documents. Any statement contained in a document
incorporated by reference herein shall be deemed to be modified or superseded
for purposes hereof to the extent that a statement contained herein or in any
subsequently filed document which also is incorporated by reference herein
modifies or supersedes such statement. Any statement so modified or superseded
shall not be deemed, except as so modified or superseded, to constitute a part
of this Registration Statement.


Item 4.   Description of Securities.
          -------------------------

     Not Applicable.


Item 5.   Interests of Named Experts and Counsel.
          --------------------------------------

     Not Applicable.

                                       2
<PAGE>

Item 6.   Indemnification of Directors and Officers.
          -----------------------------------------

          In accordance with Section 145 of the General Corporation Law of the
State of Delaware ("DGCL"), Article VII of the Registrant's Amended and Restated
Certificate of Incorporation (the "Certificate") provides that no director of
the Registrant shall be personally liable to the Registrant or its stockholders
for monetary damages for breach of fiduciary duty as a director, except for
liability (i) for any breach of the director's duty of loyalty to the Registrant
or its stockholders, (ii) for acts or omissions not in good faith or which
involve intentional misconduct or a knowing violation of law, (iii) under
Section 174, or (iv) for any transaction from which the director derived an
improper personal benefit. In addition, the Certificate provides that if the
Delaware General Corporation Law is amended to authorize the further elimination
or limitation of the personal liability of directors, then the liability of a
director of the Registrant shall be eliminated or limited to the fullest extent
permitted by the Delaware General Corporation Law, as so amended. The
Certificate further provides that any repeal of Article VII by the stockholders
or an amendment to the DGCL shall not adversely effect any right or protection
with respect to acts or omissions occurring prior to such repeal.

          Article V of the Registrant's Amended and Restated By-laws (the "By-
laws") provides for indemnification by the Registrant of its directors, officers
and certain non-officer employees under certain circumstances against expenses
(including attorneys fees, courts costs, travel expenses and additional
expenses), judgments, penalties, fines and amounts paid in settlement reasonably
incurred in connection with the defense or settlement of any threatened, pending
or completed legal proceeding in which any such person is involved by reason of
the fact that such person is or was a director, an officer or an employee of the
Registrant, or is acting in any capacity with other entities at the request of
the Registrant, if such person acted in good faith and in a manner he or she
reasonably believed to be in, or not opposed to, the best interests of the
Registrant, and with respect to criminal actions or proceedings, that such
person had no reasonable cause to believe his or her conduct was unlawful.

          The Registrant has entered into indemnification agreements with each
of its directors reflecting the foregoing provisions of its By-laws and
requiring the advancement of expenses in proceedings, if such person had no
reasonable cause to believe his or her conduct was unlawful.

          The Company carries directors' and officers' liability insurance
covering its directors and officers.

Item 7.   Exemption from Registration Claimed.
          -----------------------------------

       Not Applicable.


Item 8.   Exhibits.
          --------

       The following is a complete list of exhibits filed as part of this
Registration Statement.

Exhibits
--------

    *4.1    Plug Power Inc. Amended and Restated Certificate of Incorporation
    *4.2    Plug Power Inc. Amended and Restated By-laws
     4.3    Plug Power Inc. 1997 Membership Option Plan, as amended
    *4.4    Plug Power Inc. 1999 Stock Option and Incentive Plan
     5.1    Opinion of Goodwin, Procter & Hoar LLP as to the legality of the
            securities being registered
    23.1    Consent of Goodwin, Procter & Hoar LLP (included in Exhibit 5.1)
    23.2    Consent of PricewaterhouseCoopers LLP
    24.1    Powers of Attorney (included on signature pages to this Registration
            Statement)

*  Incorporated by reference to the relevant exhibit to the Plug Power Inc.
Registration Statement on Form S-1 (SEC File No. 333-86089), as amended, as
filed with the Securities and Exchange Commission.

Item 9.   Undertakings.
          ------------

                                       3
<PAGE>

(a)            The undersigned Registrant hereby undertakes:

       (1)     To file, during any period in which offers or sales are being
  made, a post-effective amendment to this Registration Statement:

               (i)  To include any prospectus required by Section 10(a)(3) of
       the Securities Act; and

               (ii) To reflect in the prospectus any acts or events arising
       after the effective date of the Registration Statement (or the most
       recent post-effective amendment thereof) which, individually or in the
       aggregate, represent a fundamental change in the information set forth in
       the Registration Statement;

  provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) herein do not
  apply if the information required to be included in a post-effective amendment
  by those paragraphs is contained in periodic reports filed by the undersigned
  Registrant pursuant to Section 13 or Section 15(d) of the Exchange Act that
  are incorporated by reference in the Registration Statement;

       (2)     To remove from registration by means of a post-effective
  amendment any of the securities being registered which remain unsold at the
  termination of the offering.

(b)            The undersigned Registrant hereby undertakes that, for purposes
        of determining any liability under the Securities Act, each filing of
        the registrant's annual report pursuant to Section 13(a) or 15(d) of the
        Exchange Act (and, where applicable, each filing of an employee benefit
        plan's annual report pursuant to Section 15(d) of the Exchange Act) that
        is incorporated by reference in the Registration Statement shall be
        deemed to be a new registration statement relating to the securities
        offered therein, and the offering of such securities at that time shall
        be deemed to be the initial bona fide offering thereof.

(c)            Insofar as indemnification for liabilities arising under the
        Securities Act may be permitted to directors, officers and controlling
        persons of the Registrant pursuant to the foregoing provisions, or
        otherwise, the Registrant has been advised that in the opinion of the
        Securities and Exchange Commission such indemnification is against
        public policy as expressed in the Securities Act, and is, therefore,
        unenforceable. In the event that a claim for indemnification against
        such liabilities (other than the payment by the Registrant of expenses
        incurred or paid by a director, officer or controlling person of the
        Registrant in the successful defense of any action, suit or proceeding)
        is asserted by such director, officer or controlling person in
        connection with the securities being registered, the Registrant will,
        unless in the opinion of its counsel the matter has been settled by
        controlling precedent, submit to a court of appropriate jurisdiction the
        question whether such indemnification by it is against public policy as
        expressed in the Securities Act and will be governed by the final
        adjudication of such issue.

                                       4
<PAGE>

                                  SIGNATURES

     Pursuant to the requirements of the Securities Act, Plug Power Inc.
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-8 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in Latham, New York on this 3rd day of November, 1999.

                              Plug Power Inc.


                              By: /s/ Gary Mittleman
                                  --------------------------------------
                                  Gary Mittleman
                                  President and Chief Executive Officer

                               POWER OF ATTORNEY

     KNOW ALL MEN BY THESE PRESENTS that each individual whose signature appears
below constitutes and appoints each of Gary Mittleman and Ana-Maria Galeano such
person's true and lawful attorney-in-fact and agent with full power of
substitution and resubstitution, for such person and in such person's name,
place and stead, in any and all capacities, to sign any and all amendments
(including post-effective amendments) to this Registration Statement, and to
file the same, with all exhibits thereto, and all documents in connection
therewith, with the Securities and Exchange Commission, granting unto each said
attorney-in-fact and agent full power and authority to do and perform each and
every act and thing requisite and necessary to be done in and about the
premises, as fully to all intents and purposes as such person might or could do
in person, hereby ratifying and confirming all that any said attorney-in-fact
and agent, or any substitute or substitutes of any of them, may lawfully do or
cause to be done by virtue hereof.

     Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities and on the dates indicated.


<TABLE>
<CAPTION>
          Signature                         Title                                        Date
          ---------                         -----                                        ----
<S>                                <C>                                            <C>
/s/ Gary Mittleman                 President, Chief Executive                     November 3, 1999
---------------------------        Officer (Principal Executive Officer)
Gary Mittleman                     and Director


/s/ William H. Largent             Treasurer and Chief Financial Officer          November 3, 1999
---------------------------        (Principal Financial Officer and
William H. Largent                 Principal Accounting Officer)


/s/ Michael Cudahy                 Director                                       November 3, 1999
---------------------------
Michael Cudahy


/s/ Anthony F. Earley, Jr.         Director                                       November 3, 1999
---------------------------
Anthony F. Earley, Jr.


/s/ Larry G. Garberding            Director                                       November 3, 1999
---------------------------
Larry G. Garberding
</TABLE>

                                      S-1
<PAGE>

<TABLE>
<S>                                        <C>                                    <C>
/s/ George C. McNamee                      Chairman                               November 3, 1999
---------------------------------
George C. McNamee


/s/ Dr. Walter L. Robb                     Director                               November 3, 1999
----------------------------------
Dr. Walter L. Robb


/s/ Robert L. Nardelli                     Director                               November 3, 1999
----------------------------------
Robert L. Nardelli


/s/ General John M. Shalikashvili          Director                               November 3, 1999
---------------------------------
General John M. Shalikashvili
</TABLE>

                                      S-2
<PAGE>

                                 EXHIBIT INDEX

Exhibit No.    Description
----------     -----------

   *4.1        Amended and Restated Certificate of Incorporation

   *4.2        Amended and Restated By-Laws of the Registrant

    4.3        Plug Power Inc. 1997 Membership Option Plan, as amended

   *4.4        Plug Power Inc. 1999 Stock Option and Incentive Plan

    5.1        Opinion of Goodwin, Procter & Hoar LLP as to the legality of the
               securities being registered

   23.1        Consent of Goodwin, Procter & Hoar LLP (included in Exhibit 5.1)

   23.2        Consent of PricewaterhouseCoopers LLP

   24.1        Powers of Attorney (included on signature pages to this
               Registration Statement)


*  Incorporated by reference to the relevant exhibit to the Plug Power Inc.
   Registration Statement on Form S-1 (SEC File No. 333-86089), as amended, as
   filed with the Securities and Exchange Commission.
[{"type": "S-8", "sequence": "1", "description": "FORM S-8", "secsgml_size_bytes": 19749}]
{"company-data": {"conformed-name": "PLUG POWER INC", "cik": "0001093691", "assigned-sic": "3620", "irs-number": "223672377", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-90277", "film-number": "99740609"}, "business-address": {"street1": "968 ALBANY-SHAKER ROAD", "city": "LATHAM", "state": "NY", "zip": "12110", "phone": "5187827700"}, "mail-address": {"street1": "968 ALBANY-SHAKER ROAD", "city": "LATHAM", "state": "NY", "zip": "12110"}}
As filed with the Securities and Exchange Commission on November 3, 1999

                                   Registration Statement No. 333-______________
================================================================================

                      SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C. 20549

                            ----------------------

                                   FORM S-8
                            REGISTRATION STATEMENT
                                     UNDER
                          THE SECURITIES ACT OF 1933

                            ----------------------

                                PLUG POWER INC.
            (Exact name of Registrant as Specified in Its Charter)

          Delaware                                     22-3672377
  (State of Incorporation)                (I.R.S. Employer Identification No.)

                            968 Albany-Shaker Road
                               Latham, NY 12110
                                (518) 782-7700
  (Address, including zip code, and telephone number, including area code, of
                   Registrant's principal executive offices)

                  Plug Power Inc. 1997 Membership Option Plan
             Plug Power Inc. 1999 Stock Option and Incentive Plan
                           (Full Title of the Plan)
                           ------------------------

                                Gary Mittleman
                     President and Chief Executive Officer
                                Plug Power Inc.
                            968 Albany-Shaker Road
                               Latham, NY 12110
                                (518) 782-7700

(Name, address, including zip code, and telephone number, including area code,
                             of agent for service)

                            ----------------------

                                With a copy to:

                          Robert P. Whalen, Jr., P.C.
                         Goodwin, Procter & Hoar LLP
                                Exchange Place
                       Boston, Massachusetts 02109-2881
                                (617) 570-1000

                            -----------------------
CALCULATION OF REGISTRATION FEE
==================================================================================================================================
Title of Securities Being Registered    Amounts to be         Proposed Maximum             Proposed Maximum          Amount of
                                        Registered (1)  Offering Price Per Share (2)   Aggregate Offering Price   Registration Fee
----------------------------------------------------------------------------------------------------------------------------------
Common Stock, par value $.01 per           1,434,350             $ 1.00 (2)                   $ 1,434,350               $   399
           share                             579,189             $ 5.00 (2)                   $ 2,895,945               $   805
                                             587,700             $ 6.67 (2)                   $ 3,919,959               $ 1,090
                                             726,900             $11.00 (2)                   $ 7,995,900               $ 2,223
                                           2,343,052             $15.88 (3)                   $37,207,666               $10,344
                                        ------------                                                                    -------

                                           5,671,191 (total)                                                            $14,861
==================================================================================================================================
(1)  This Registration Statement also relates to such indeterminate number of
     additional shares of Plug Power Inc. Common Stock as may be required
     pursuant to the 1997 Membership Option Plan and the 1999 Stock Option and
     Incentive Plan in the event of a stock dividend, reverse stock split,
     split-up, recapitalization, forfeiture of stock under the plan or other
     similar event.

(2)  Determined pursuant to Rule 457(h) under the  under the Securities Act of
     1933, as amended (the "Securities Act").

(3)  This estimate is made pursuant to Rule 457(c) and (h) of the Securities Act
     solely for the purposes of determining the amount of the registration fee.
     The registration fee is based upon the average of the high and low prices
     for the Registrant's Common Stock, par value $0.01 per share, as reported
     on The Nasdaq National Market on November 1, 1999.

================================================================================
PART I

             INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

Item 1.   Plan Information.*
          ----------------

Item 2.   Registrant Information and Employee Plan Annual Information.*
          -----------------------------------------------------------

     * Information required by Part I to be contained in the Section 10(a)
Prospectuses is omitted from this Registration Statement in accordance with Rule
428 under the Securities Act of 1933 (the "Securities Act") and the Introductory
Note to Part I of Form S-8.

                                    PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3.   Incorporation of Certain Documents by Reference.
          -----------------------------------------------

     Plug Power Inc. (the "Registrant") hereby incorporates by reference:

     the description of the Registrant's Common Stock contained in the
     Registration Statement on Form 8-A (Registration Statement No. 333-86089),
     dated October 1, 1999, as filed with the Securities and Exchange Commission
     on October 1, 1999 pursuant to Section 12(g) of the Securities Exchange Act
     of 1934, as amended.

     In addition, all documents subsequently filed with the Securities and
Exchange Commission by the Registrant pursuant to Sections 13(a), 13(c), 14 and
15(d) of the Exchange Act, prior to the filing of a post-effective amendment
hereto that indicates that all securities offered hereunder have been sold or
which deregisters all securities then remaining unsold, shall be deemed to be
incorporated by reference in this Registration Statement and to be a part hereof
from the date of filing of such documents. Any statement contained in a document
incorporated by reference herein shall be deemed to be modified or superseded
for purposes hereof to the extent that a statement contained herein or in any
subsequently filed document which also is incorporated by reference herein
modifies or supersedes such statement. Any statement so modified or superseded
shall not be deemed, except as so modified or superseded, to constitute a part
of this Registration Statement.

Item 4.   Description of Securities.
          -------------------------

     Not Applicable.

Item 5.   Interests of Named Experts and Counsel.
          --------------------------------------

     Not Applicable.

                                       2
Item 6.   Indemnification of Directors and Officers.
          -----------------------------------------

          In accordance with Section 145 of the General Corporation Law of the
State of Delaware ("DGCL"), Article VII of the Registrant's Amended and Restated
Certificate of Incorporation (the "Certificate") provides that no director of
the Registrant shall be personally liable to the Registrant or its stockholders
for monetary damages for breach of fiduciary duty as a director, except for
liability (i) for any breach of the director's duty of loyalty to the Registrant
or its stockholders, (ii) for acts or omissions not in good faith or which
involve intentional misconduct or a knowing violation of law, (iii) under
Section 174, or (iv) for any transaction from which the director derived an
improper personal benefit. In addition, the Certificate provides that if the
Delaware General Corporation Law is amended to authorize the further elimination
or limitation of the personal liability of directors, then the liability of a
director of the Registrant shall be eliminated or limited to the fullest extent
permitted by the Delaware General Corporation Law, as so amended. The
Certificate further provides that any repeal of Article VII by the stockholders
or an amendment to the DGCL shall not adversely effect any right or protection
with respect to acts or omissions occurring prior to such repeal.

          Article V of the Registrant's Amended and Restated By-laws (the "By-
laws") provides for indemnification by the Registrant of its directors, officers
and certain non-officer employees under certain circumstances against expenses
(including attorneys fees, courts costs, travel expenses and additional
expenses), judgments, penalties, fines and amounts paid in settlement reasonably
incurred in connection with the defense or settlement of any threatened, pending
or completed legal proceeding in which any such person is involved by reason of
the fact that such person is or was a director, an officer or an employee of the
Registrant, or is acting in any capacity with other entities at the request of
the Registrant, if such person acted in good faith and in a manner he or she
reasonably believed to be in, or not opposed to, the best interests of the
Registrant, and with respect to criminal actions or proceedings, that such
person had no reasonable cause to believe his or her conduct was unlawful.

          The Registrant has entered into indemnification agreements with each
of its directors reflecting the foregoing provisions of its By-laws and
requiring the advancement of expenses in proceedings, if such person had no
reasonable cause to believe his or her conduct was unlawful.

          The Company carries directors' and officers' liability insurance
covering its directors and officers.

Item 7.   Exemption from Registration Claimed.
          -----------------------------------

       Not Applicable.

Item 8.   Exhibits.
          --------

       The following is a complete list of exhibits filed as part of this
Registration Statement.

Exhibits
--------

    *4.1    Plug Power Inc. Amended and Restated Certificate of Incorporation
    *4.2    Plug Power Inc. Amended and Restated By-laws
     4.3    Plug Power Inc. 1997 Membership Option Plan, as amended
    *4.4    Plug Power Inc. 1999 Stock Option and Incentive Plan
     5.1    Opinion of Goodwin, Procter & Hoar LLP as to the legality of the
            securities being registered
    23.1    Consent of Goodwin, Procter & Hoar LLP (included in Exhibit 5.1)
    23.2    Consent of PricewaterhouseCoopers LLP
    24.1    Powers of Attorney (included on signature pages to this Registration
            Statement)

*  Incorporated by reference to the relevant exhibit to the Plug Power Inc.
Registration Statement on Form S-1 (SEC File No. 333-86089), as amended, as
filed with the Securities and Exchange Commission.

Item 9.   Undertakings.
          ------------

                                       3
(a)            The undersigned Registrant hereby undertakes:

       (1)     To file, during any period in which offers or sales are being
  made, a post-effective amendment to this Registration Statement:

               (i)  To include any prospectus required by Section 10(a)(3) of
       the Securities Act; and

               (ii) To reflect in the prospectus any acts or events arising
       after the effective date of the Registration Statement (or the most
       recent post-effective amendment thereof) which, individually or in the
       aggregate, represent a fundamental change in the information set forth in
       the Registration Statement;

  provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) herein do not
  apply if the information required to be included in a post-effective amendment
  by those paragraphs is contained in periodic reports filed by the undersigned
  Registrant pursuant to Section 13 or Section 15(d) of the Exchange Act that
  are incorporated by reference in the Registration Statement;

       (2)     To remove from registration by means of a post-effective
  amendment any of the securities being registered which remain unsold at the
  termination of the offering.

(b)            The undersigned Registrant hereby undertakes that, for purposes
        of determining any liability under the Securities Act, each filing of
        the registrant's annual report pursuant to Section 13(a) or 15(d) of the
        Exchange Act (and, where applicable, each filing of an employee benefit
        plan's annual report pursuant to Section 15(d) of the Exchange Act) that
        is incorporated by reference in the Registration Statement shall be
        deemed to be a new registration statement relating to the securities
        offered therein, and the offering of such securities at that time shall
        be deemed to be the initial bona fide offering thereof.

(c)            Insofar as indemnification for liabilities arising under the
        Securities Act may be permitted to directors, officers and controlling
        persons of the Registrant pursuant to the foregoing provisions, or
        otherwise, the Registrant has been advised that in the opinion of the
        Securities and Exchange Commission such indemnification is against
        public policy as expressed in the Securities Act, and is, therefore,
        unenforceable. In the event that a claim for indemnification against
        such liabilities (other than the payment by the Registrant of expenses
        incurred or paid by a director, officer or controlling person of the
        Registrant in the successful defense of any action, suit or proceeding)
        is asserted by such director, officer or controlling person in
        connection with the securities being registered, the Registrant will,
        unless in the opinion of its counsel the matter has been settled by
        controlling precedent, submit to a court of appropriate jurisdiction the
        question whether such indemnification by it is against public policy as
        expressed in the Securities Act and will be governed by the final
        adjudication of such issue.

                                       4
SIGNATURES

     Pursuant to the requirements of the Securities Act, Plug Power Inc.
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-8 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in Latham, New York on this 3rd day of November, 1999.

                              Plug Power Inc.

                              By: /s/ Gary Mittleman
                                  --------------------------------------
                                  Gary Mittleman
                                  President and Chief Executive Officer

                               POWER OF ATTORNEY

     KNOW ALL MEN BY THESE PRESENTS that each individual whose signature appears
below constitutes and appoints each of Gary Mittleman and Ana-Maria Galeano such
person's true and lawful attorney-in-fact and agent with full power of
substitution and resubstitution, for such person and in such person's name,
place and stead, in any and all capacities, to sign any and all amendments
(including post-effective amendments) to this Registration Statement, and to
file the same, with all exhibits thereto, and all documents in connection
therewith, with the Securities and Exchange Commission, granting unto each said
attorney-in-fact and agent full power and authority to do and perform each and
every act and thing requisite and necessary to be done in and about the
premises, as fully to all intents and purposes as such person might or could do
in person, hereby ratifying and confirming all that any said attorney-in-fact
and agent, or any substitute or substitutes of any of them, may lawfully do or
cause to be done by virtue hereof.

     Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities and on the dates indicated.
Signature                         Title                                        Date
          ---------                         -----                                        ----
/s/ Gary Mittleman                 President, Chief Executive                     November 3, 1999
---------------------------        Officer (Principal Executive Officer)
Gary Mittleman                     and Director

/s/ William H. Largent             Treasurer and Chief Financial Officer          November 3, 1999
---------------------------        (Principal Financial Officer and
William H. Largent                 Principal Accounting Officer)

/s/ Michael Cudahy                 Director                                       November 3, 1999
---------------------------
Michael Cudahy

/s/ Anthony F. Earley, Jr.         Director                                       November 3, 1999
---------------------------
Anthony F. Earley, Jr.

/s/ Larry G. Garberding            Director                                       November 3, 1999
---------------------------
Larry G. Garberding
S-1
/s/ George C. McNamee                      Chairman                               November 3, 1999
---------------------------------
George C. McNamee

/s/ Dr. Walter L. Robb                     Director                               November 3, 1999
----------------------------------
Dr. Walter L. Robb

/s/ Robert L. Nardelli                     Director                               November 3, 1999
----------------------------------
Robert L. Nardelli

/s/ General John M. Shalikashvili          Director                               November 3, 1999
---------------------------------
General John M. Shalikashvili
S-2
EXHIBIT INDEX

Exhibit No.    Description
----------     -----------

   *4.1        Amended and Restated Certificate of Incorporation

   *4.2        Amended and Restated By-Laws of the Registrant

    4.3        Plug Power Inc. 1997 Membership Option Plan, as amended

   *4.4        Plug Power Inc. 1999 Stock Option and Incentive Plan

    5.1        Opinion of Goodwin, Procter & Hoar LLP as to the legality of the
               securities being registered

   23.1        Consent of Goodwin, Procter & Hoar LLP (included in Exhibit 5.1)

   23.2        Consent of PricewaterhouseCoopers LLP

   24.1        Powers of Attorney (included on signature pages to this
               Registration Statement)

*  Incorporated by reference to the relevant exhibit to the Plug Power Inc.
   Registration Statement on Form S-1 (SEC File No. 333-86089), as amended, as
   filed with the Securities and Exchange Commission.