SEC Form 4

FORM 4
[ ] Check this box if no longer
subject to Section 16. Form 4 or Form
5 oblibations may continue.
See Instruction 1(b). UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C.  20549
STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility
Holding Company Act of 1935 or Section 30(f) of the Investment Company Act of 1940 OMB APPROVAL

OMB Number: 3235-0287
Expires: December 31, 2001
Estimated average burden
hours per response. . . . . 0.5

1. Name and Address of Reporting Person^*
Mechanical Technology Incorporated (Last)                      (First)                      (Middle) 431 New Karner Road

(Street) Albany, NY     12205
(City)                      (State)                      (Zip) USA 2. Issuer Name and Ticker
    or Trading Symbol

Plug Power Inc.   PLUG3. I.R.S. Identification
    Number of Reporting
    Person, if an entity
    (voluntary)

14-1462255 4. Statement for
    (Month/Year)

    June 2001

5. If Amendment,
    Date of Original
     (Month/Year)
6. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
                        Director              X          10% Owner
                        Officer                             Other

Officer/Other
Description                               7. Individual or Joint/Group
    Filing (Check Applicable Line)

X   Individual Filing
      Joint/Group Filing

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1. Title of Security     (Instr. 3)	2. Transaction Date     (Month/Day/Year)	3. Transaction     Code     and     Voluntary     Code     (Instr. 8) Code  |  V	4. Securities Acquired (A) or Disposed (D) Of     (Instr. 3, 4, and 5)         Amount      |         A/D         |         Price	5. Amount of     Securities     Beneficially     Owned at     End of Month      (Instr. 3 and 4)	6. Owner-     ship     Form:     Direct(D)     or     Indirect (I)      (Instr. 4)	7. Nature of      Indirect      Beneficial      Ownership     (Instr. 4)
Plug Power Inc. - Common Stock	06/04/2001	S |	30,000.00   |           D           |   $30.12		D
Plug Power Inc. - Common Stock	06/05/2001	S |	25,000.00   |           D           |   $29.49		D
Plug Power Inc. - Common Stock	06/06/2001	S |	45,000.00   |           D           |   $30.77		D
Plug Power Inc. - Common Stock	06/07/2001	S |	45,000.00   |           D           |   $29.76		D
Plug Power Inc. - Common Stock	06/08/2001	S |	2,500.00   |           D           |   $28.50		D
Plug Power Inc. - Common Stock	06/11/2001	S |	70,000.00   |           D           |   $27.30		D
Plug Power Inc. - Common Stock	06/12/2001	S |	30,000.00   |           D           |   $26.96		D
Plug Power Inc. - Common Stock	06/13/2001	S |	15,000.00   |           D           |   $26.23		D
Plug Power Inc. - Common Stock	06/14/2001	S |	12,500.00   |           D           |   $23.30		D
Plug Power Inc. - Common Stock	06/15/2001	S |	7,075.00   |           D           |   $21.30	11,994,315.00	D

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

(over)
SEC 1474 (3-99)

Mechanical Technology Incorporated - June 2001

Form 4 (continued)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security
    (Instr. 3) 2. Conver-
    sion or
    Exercise
    Price of
    Deri-
    vative
     Security 3. Transaction
    Date

    (Month/
    Day/
    Year) 4. Transaction
    Code
    and
    Voluntary (V)
    Code
    (Instr.8)





Code | V     5. Number of Derivative
    Securities Acquired (A)
    or Disposed (D) Of

    (Instr. 3,4 and 5) 6. Date Exercisable(DE) and
    Expiration Date(ED)
    (Month/Day/Year)








  (DE)     |     (ED)   7. Title and Amount of
    Underlying Securities
    (Instr. 3 and 4) 8. Price
    of
    Derivative
    Security
    (Instr.5) 9. Number of
    Derivative
    Securities
    Beneficially
    Owned
    at End of
    Month
    (Instr.4) 10.
Owner-
ship
Form of
Deriv-
ative
Security:
Direct
(D)
or
Indirect
(I) 11. Nature of
      Indirect
      Beneficial
      Ownership
       (Instr.4)

Explanation of Responses :

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations.
        See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

Note:   File three copies of this Form, one of which must be manually signed. If space is insufficient,
            See Instruction 6 for procedure.

Potential persons who are to respond to the collection of information contained in this form are not
required to respond unless the form displays a currently valid OMB number. ________________________________            07-09-2001    
** Signature of Reporting Person                         Date


Mechanical Technology Incorporated


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SEC 1474 (3-99)