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                              February 10, 2021

       Paul Middleton
       Chief Financial Officer
       Plug Power, Inc.
       968 Albany Shaker Road
       Latham, NY 12110

                                                        Re: Plug Power, Inc.
                                                            Form 10-K for the
Fiscal Year Ended December 31, 2019
                                                            Filed March 10,
2020
                                                            Form 8-K filed
November 9, 2020
                                                            File No. 001-34392

       Dear Mr. Middleton:

              We have reviewed your January 14, 2021 response to our comment
letter and have the
       following comments. In some of our comments, we may ask you to provide
us with information
       so we may better understand your disclosure.

              Please respond to these comments within ten business days by
providing the requested
       information or advise us as soon as possible when you will respond. If
you do not believe our
       comments apply to your facts and circumstances, please tell us why in
your response.

            After reviewing your response to these comments, we may have
additional
       comments. Unless we note otherwise, our references to prior comments are
to comments in our
       December 16, 2020 letter.

       Form 10-K for the Fiscal Year Ended December 31, 2019

       15. Employee Benefit Plans, page F-36

   1.                                                   We have read your
response to comment 4 and have the following comments:

                                                              Considering it
appears your common stock has been publicly traded for a period
                                                            exceeding the
contractual term of your options and you have had option exercises for
                                                            the past several
years, please clarify how you determined that your historical exercise
                                                            data is limited and
cannot be relied upon in estimating the expected term.

                                                              To the extent you
can justify use of the simplified method, please revise future filings
                                                            to provide the
disclosures suggested by SAB Topic 14D, including the reasons why
 Paul Middleton
FirstName
Plug Power,LastNamePaul Middleton
            Inc.
Comapany10,
February   NamePlug
             2021   Power, Inc.
February
Page 2 10, 2021 Page 2
FirstName LastName
              the simplified method was used, the types of share option grants
for which the
              method was used if the method was not used for all share option
grants, and the
              periods for which the method was used if the method was not used
in all periods. In
              your response, please provide us with your proposed disclosure.
18. Commitments and Contingencies , page F-42

2.       We have read your response to comment 5. Please clarify if these
financing obligations
         represent cash received that are repayable from future revenues, as
indicated in ASC 470-
         10-25-1, or, as your response suggests, if the amounts represent the
prepayment of
         revenues. In assisting us with an understanding of your accounting,
please provide us
         with an example of this type of transaction illustrating the involved
parties, payments, and
         performance obligations and provide us with example journal entries
recorded upon and
         subsequent to recognition of the financing obligation.
Form 8-K filed November 9, 2020
Exhibit 99.1, page 1

3.       We have read your response to prior comments 6 and 7 and have the
following comments:

                Please provide us with all proposed disclosures you intend to
make in response to our
              comments.

                You indicate that the invoice value of equipment included in
your gross billings
              metric is    measured on a relative basis using cash value within
contracts.    Please
              clarify what you mean by this statement and explain why it
appears you do not use
              the actual amount invoiced.

                As previously requested, please amend your filing to remove the
warrant provision
              adjustments, including the provision for loss contracts, from all
non-
              GAAP measures. Please ensure that the amended filing complies
with all comments
              issued during our review.

                Considering operating lease expense is a normal, recurring cash
operating expense,
              please remove the    Right-of-use asset depreciation and interest
associated with PPA
              financings    adjustment from your Adjusted EBITDA calculation.
Considering the
              adjustment relates to operating leases, as opposed to finance
leases, please also
              clarify why the adjustment includes right-of-use depreciation and
interest expense.
 Paul Middleton
Plug Power, Inc.
February 10, 2021
Page 3

        You may contact Andrew Blume at (202) 551-3254 or Melissa Raminpour at
(202) 551-
3379 if you have questions regarding comments on the financial statements and
related matters.



FirstName LastNamePaul Middleton                           Sincerely,
Comapany NamePlug Power, Inc.
                                                           Division of
Corporation Finance
February 10, 2021 Page 3                                   Office of
Manufacturing
FirstName LastName