EXHIBIT 10.2
FIRST AMENDMENT TO ASSET PURCHASE AGREEMENT
     This First Amendment to Asset Purchase Agreement is dated March 31, 2008 by
and between Metretek, Incorporated, a Florida corporation (“Seller”),
PowerSecure International, Inc., a Delaware corporation (“PowerSecure”), and
Mercury Instruments LLC, an Ohio limited liability company (“Purchaser”), who
agree as follows:
     1. Recitals. Pursuant to an Asset Purchase Agreement dated March 14, 2008
(the “Purchase Agreement”), Purchaser agreed to acquire certain assets of the
Seller. Pursuant to Section 14.9 of the Purchase Agreement, the Purchaser,
Seller and PowerSecure desire to amend the Purchase Agreement in certain
respects.
     2. Amendment. The Purchase Agreement is hereby amended as follows:
          (a) Change the period at the end of Section 2.1(a)(xv) to a comma and
add the following: “including the license payments set forth on
Schedule 2.1(a)(xv) attached hereto (the “Acquired License Payments”).
          (b) Add the following after the word “Date” in Section 2.1(b)(v):
“except for the Acquired License Payments”.
          (c) Add the following as new Section 2.1(d):
          (d) All payments received with respect to the Acquired License
Payments, whether received prior to or after the Closing Date, shall be paid
over to the Purchaser (if not paid directly to the Purchaser) promptly, and in
no event more than ten (10) Business Days after receipt of such payments.
          (d) In the last sentence of Section 4, add the words “day following
the” before the words “Closing Date”.
     3. Confirmation. In all other respects, the Purchase Agreement is hereby
ratified, confirmed and approved.
     Signed the date above.

          METRETEK, INCORPORATED   POWERSECURE INTERNATIONAL, INC.   By:   /s/
Christopher T. Hutter   By:   /s/ Christopher T. Hutter              
Christopher T. Hutter,     Christopher T. Hutter,   Vice President and Chief
Financial Officer     Vice President and Chief Financial Officer   MERCURY
INSTRUMENTS LLC         By:   /s/ Gareth Y. Hudson                  
Gareth Y. Hudson, President