Filed by Plug Power Inc.
              Pursuant to Rule 425 under the Securities Act of 1933, as amended.

                                                  Subject Company: H Power Corp.
                                                  Commission File No. 333-101567

[H POWER LOGO APPEARS HERE]

                                  H POWER CORP.
                              60 Montgomery Street
                          Belleville, New Jersey 07109
                                 (973) 450-4400

                             AN IMPORTANT REMINDER!

March 7, 2003

Dear Stockholder:

     We have previously mailed you proxy materials in connection with the
upcoming special meeting of H Power stockholders, which has been called to vote
upon a proposed merger of H Power with Plug Power. The meeting is scheduled to
be held on Tuesday, March 25, 2003. According to our latest records, your proxy
instructions for this meeting have not yet been received.

     Your Board of Directors recommends that stockholders vote in favor of the
proposal to adopt and approve the Agreement and Plan of Merger, a copy and the
material details of which are included in the proxy material previously sent to
you, dated February 12, 2003. PLEASE PROMPTLY TAKE ACTION TO ENSURE THAT YOUR H
POWER SHARES ARE REPRESENTED AT THE SPECIAL MEETING.

     Your vote is very important, regardless of the number of H Power shares you
currently own. Since the time until the special meeting is short, we urge you to
vote your shares today, by signing, dating, and returning the enclosed proxy
card in the envelope provided. Acting now will help ensure that your proxy
instructions are received in time for the meeting. Thank you for your prompt
attention.

                                           Sincerely,

                                           /s/ H. Frank Gibbard
                                           --------------------------
                                           Dr. H. Frank Gibbard
                                           Chief Executive Officer



          Additional Information About the Merger and Where to Find It.

     On February 12, 2003, Plug Power filed a registration statement with the
SEC containing a definitive joint proxy statement/prospectus regarding the
proposed merger with H Power. On or about February 13, 2003, Plug Power and H
Power mailed the joint proxy statement/prospectus to their respective
stockholders in connection with the proposed merger. INVESTORS AND SECURITY
HOLDERS OF PLUG POWER AND H POWER ARE URGED TO READ THE JOINT PROXY
STATEMENT/PROSPECTUS AND ANY OTHER RELEVANT MATERIALS FILED BY PLUG POWER OR H
POWER WITH THE SEC BECAUSE THEY CONTAIN, OR WILL CONTAIN, IMPORTANT INFORMATION
ABOUT PLUG POWER, H POWER AND THE MERGER. Investors and security holders may
obtain a copy of the joint proxy statement/prospectus (and other relevant
materials when they become available) at the SEC's web site, www.sec.gov. The
joint proxy statement/prospectus (and other relevant materials when they become
available) may also be obtained free of charge from Plug Power by directing a
request to Plug Power at 968 Albany-Shaker Road, Latham, NY 12110, Attention:
Roger Saillant, President; and from H Power by directing a request to H Power at
60 Montgomery Street, Belleville, New Jersey, 07109, Attention: William L. Zang.
In addition to the registration statement that has been filed by Plug Power in
connection with the transaction, and the joint proxy statement/prospectus mailed
to the stockholders of Plug Power and H Power, each of Plug Power and H Power
files annual, quarterly and special reports, proxy statements and other
information with the SEC. Investors and security holders may read and copy any
of these reports, statements and other information at the SEC's public reference
rooms located at 450 5th Street, N.W., Washington, D.C., 20549, or any of the
SEC's other public reference rooms. Investors and security holders should call
the SEC at 1-800-SEC-0330 for further information on these public reference
rooms. The reports, statements and other information filed by Plug Power and H
Power with the SEC are also available for free at the SEC's web site at
www.sec.gov. A free copy of these reports, statements and other information may
also be obtained from Plug Power and H Power.

     Plug Power, H Power and their respective executive officers and directors
may be considered participants in the solicitation of proxies from the
stockholders of Plug Power and H Power in favor of the merger. A description of
the interests of Plug Power's executive officers and directors in Plug Power is
set forth in the joint proxy statement/prospectus. A description of the
interests of H Power's executive officers and directors in H Power is also set
forth in the joint proxy statement/prospectus.