Under the Securities Exchange Act of 1934
(Amendment No. 5)

(Name of Issuer)

(Title of Class of Securities)

(CUSIP Number)

(Name, Address and Telephone Number of Person
Authorized to Receive Notices and Communications)

(Date of Event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of Rule 13d-1(e), 13d-1(f) or 13d-1(g), check the following box o

Note. Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See Rule 13d-7(b) for other parties to whom copies are to be sent.

^* 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 (the “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).

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SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

(Amendment No. 5)

Statement of

Smart Hydrogen Inc.

Pursuant to Section 13(d) of the Securities Exchange Act of 1934

in respect of

Plug Power Inc.

Explanatory Note:  This Amendment No. 5 (this “Amendment No. 5”) amends and supplements the Statement on Schedule 13D of Smart Hydrogen Inc. (“Smart Hydrogen”), MMC Norilsk Nickel (“Norilsk Nickel”), Clayburn Development Inc. (“Clayburn”), Branton Limited (“Branton”), and Vladimir O. Potanin (“Mr. Potanin”), originally filed on April 20, 2006 (the “Original Statement”), as amended by Amendment No. 1 filed on June 29, 2006 (“Amendment No. 1”), Amendment No. 2 filed on April 24, 2008 (“Amendment 2”), Amendment No. 3 filed on May 15, 2008 (“Amendment 3”), and Amendment No. 4 filed on October 21, 2008 (“Amendment No. 4” and collectively with the Original Statement, Amendment No. 1, Amendment No. 2, Amendment No. 3, and this Amendment No. 5, the “Statement”).

As previously disclosed in Amendment No. 4, on October 14, 2008, Smart Hydrogen and OJSC «Third Generation Company of the Wholesale Electricity Market», an open joint stock company organized under the laws of the Russian Federation and subsidiary of Norilsk Nickel (“WGC-3”), executed a Share Purchase Agreement (the “Share Purchase Agreement”) whereby WGC-3 agreed to purchase Smart Hydrogen’s entire beneficial interest in Plug Power Inc. (the “Issuer”).  This Amendment No. 5 is being filed to disclose the consummation on December 20, 2008 of the transaction contemplated by such Share Purchase Agreement.

Item 2.  Identity and Background

Item 2 of the Statement is hereby amended and supplemented as follows:

Exhibit A to this Amendment No. 5 contains information regarding the executive officers and directors of Norilsk Nickel as of the date hereof.

Item 4.   Purpose of the Transaction

Item 4 of the Statement is hereby amended and supplemented as follows:

This Statement relates to the disposition by Smart Hydrogen, Clayburn, and Branton of beneficial ownership of 44,626,939 shares of Common Stock, representing approximately 34.89% of the Issuer’s outstanding Common Stock.  These shares consist of 5,126,939 shares of Common Stock and 395,000 shares of Class B Capital Stock which automatically converted into 39,500,000 shares of Common Stock upon the sale thereof to WGC-3.  The ownership percentages contained in this Amendment No. 5 and in the cover pages hereto are based upon

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information contained in the Issuer’s most recently available filing with the Securities and Exchange Commission that, as of as of November 4, 2008, 88,387,130 shares of Common Stock and 395,000 shares of Class B Capital Stock were outstanding.

As previously disclosed, on October 14, 2008, Smart Hydrogen and WGC-3 agreed that Smart Hydrogen would sell its entire beneficial interest in the Issuer to WGC-3.  On December 20, 2008, Smart Hydrogen and WGC-3 completed the sale of Smart Hydrogen’s entire beneficial interest in the Issuer to WGC-3.  Pursuant to the terms of the Issuer’s Certificate of Designations relating to the Class B Capital Stock, upon the sale of such Class B Capital Stock, the 395,000 shares of Class B Capital Stock automatically converted into 39,500,000 shares of Common Stock.  As a result of the conversion of the Class B Capital Stock into Common Stock, the holder of such shares no longer has the rights and obligations associated with the Class B Capital Stock under the Certificate of Designations and the Investor Rights Agreement dated as of June 29, 2006, as amended.  Those rights and obligations were described in Amendment No. 1 and include, among other things, the right to appoint four directors to the Issuer’s board of directors, certain veto rights, and certain voting support obligations.

Except as set forth in this Statement, none of the persons listed in Item 2 (collectively, the “Reporting Persons”) has any present plans or proposals that relate to or would result in the occurrence of any of the events specified in clauses (a) through (j) of the instructions to Item 4 of Schedule 13D.  The Reporting Persons reserve the right to formulate plans or make proposals, and take such actions with respect to their investment in the Issuer, including any action that relates to or would result in the occurrence of any or all of the events specified in clauses (a) through (j) of the instructions to Item 4 of Schedule 13D, and any other actions, as they may determine.  The Reporting Persons intend to review continually their investment in the Issuer, depending upon future evaluations of the business prospects of the Issuer and upon other developments, including but not limited to, general economic and business conditions and stock market conditions.  The Reporting Persons may determine to increase or decrease their equity position in the Issuer by acquiring additional shares of disposing of some of the shares they may hold, in each case in accordance with the terms and conditions contained in the agreements executed at the closing of the initial investment by Smart Hydrogen.

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SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this Amendment No. 5 is true, complete and correct.

Dated:  December 23, 2008

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EXHIBIT A

OFFICERS AND DIRECTORS OF PERSONS NAMED IN ITEM 2

Executive Officers of MMC Norilsk Nickel

A-1

Board of Directors of MMC Norilsk Nickel

A-2

A-3

EXHIBIT B

AGREEMENT RELATING TO JOINT FILING OF SCHEDULE 13D/A

In accordance with Rule 13d-1(k)(1)(iii) under the Securities Exchange Act of 1934, as amended, the persons named below agree to the joint filing on behalf of each of them of an Amendment No. 5 to the Statement on Schedule 13D filed on December 23, 2008 (including additional amendments thereto) with respect to the securities of Plug Power Inc.  This Joint Filing Agreement shall be filed as an Exhibit to such Statement.

Date:  December 23, 2008

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