<PAGE>

                                                                     Exhibit 4.3

                          SPECIMEN WARRANT CERTIFICATE

NUMBER: ___________________________              WARRANTS: __________________ -W

                          (SEE REVERSE SIDE FOR LEGEND)
         (THIS WARRANT WILL BE VOID IF NOT EXERCISED PRIOR TO 5:00 P.M.
                NEW YORK CITY LOCAL TIME, _______________, 2011)

                        ENERGY SERVICES ACQUISITION CORP.

                                                              CUSIP: ___________

                                     WARRANT

     THIS CERTIFIES THAT, for value received, __________________ is the
registered holder of a Warrant or Warrants expiring ___________________, 2011
(the "WARRANT") to purchase one fully paid and non-assessable share of Common
Stock, par value $0.0001 per share ("SHARES"), of Energy Services Acquisition
Corp., a Delaware corporation (the "COMPANY"), for each Warrant evidenced by
this Warrant Certificate. The Warrant entitles the holder thereof to purchase
from the Company, commencing on the later of (i) the completion by the Company
of a merger, capital stock exchange, asset acquisition or other similar business
combination or (ii) __________________, 2007, such number of Shares of the
Company at the price of $5.00 per share, upon surrender of this Warrant
Certificate and payment of the Warrant Price at the office or agency of the
Warrant Agent, Continental Stock Transfer & Trust Company (such payment to be
made by check made payable to the Warrant Agent), but only subject to the
conditions set forth herein and in the Warrant Agreement between the Company and
Continental Stock Transfer & Trust Company. The Warrant Agreement provides that
upon the occurrence of certain events the Warrant Price and the number of
Warrant Shares purchasable hereunder, set forth on the face hereof, may, subject
to certain conditions, be adjusted. The term Warrant Price as used in this
Warrant Certificate refers to the price per Share at which Shares may be
purchased at the time the Warrant is exercised.

     No fraction of a Share will be issued upon any exercise of a Warrant. If
the holder of a Warrant would be entitled to receive a fraction of a Share upon
any exercise of a Warrant, the Company shall, upon such exercise, round up or
down to the nearest whole number the number of Shares to be issued to such
holder.

     Upon any exercise of the Warrant for less than the total number of full
Shares provided for herein, there shall be issued to the registered holder
hereof or his assignee a new Warrant Certificate covering the number of Shares
for which the Warrant has not been exercised.

     Warrant Certificates, when surrendered at the office or agency of the
Warrant Agent by the registered holder hereof in person or by attorney duly
authorized in writing, may be exchanged in the manner and subject to the
limitations provided in the Warrant Agreement, but without payment of any
service charge, for another Warrant Certificate or Warrant Certificates of like
tenor and evidencing in the aggregate a like number of Warrants.

     Upon due presentment for registration of transfer of the Warrant
Certificate at the office or agency of the Warrant Agent, a new Warrant
Certificate or Warrant Certificates of like tenor and evidencing in the
aggregate a like number of Warrants shall be issued to the transferee in
exchange for this Warrant Certificate, subject to the limitations provided in
the Warrant Agreement, without charge except for any applicable tax or other
governmental charge.

     The Company and the Warrant Agent may deem and treat the registered holder
as the absolute owner of this Warrant Certificate (notwithstanding any notation
of ownership or other writing hereon made by anyone), for the purpose of any
exercise hereof, of any distribution to the registered holder, and for all other
purposes, and neither the Company nor the Warrant Agent shall be affected by any
notice to the contrary.

     This Warrant does not entitle the registered holder to any of the rights of
a stockholder of the Company.

<PAGE>

     The Company reserves the right to call the Warrant, with the prior consent
of Ferris, Baker Watts, Incorporated, at any time prior to its exercise, with a
notice of call in writing to the holders of record of the Warrant, giving 30
days' prior written notice of such call at any time after the Warrant becomes
exercisable if the last sale price of the Shares has been at least $8.50 per
share for any 20 trading days within a 30 trading day period ending on the third
business day prior to the date on which notice of such call is given. The call
price of the Warrants is to be $0.01 per Warrant. Any Warrant either not
exercised or tendered back to the Company by the end of the date specified in
the notice of call shall be canceled on the books of the Company and have no
further value except for the $0.01 call price.

Dated:
       -----------------------------


-------------------------------------   ----------------------------------------
Chief Executive Officer                 Secretary


                                        2

<PAGE>

                                SUBSCRIPTION FORM

To Be Executed by the Registered Holder in Order to Exercise Warrants

     The undersigned Registered Holder irrevocably elects to exercise Warrants
represented by this Warrant Certificate, and to purchase the shares of Common
Stock issuable upon the exercise of such Warrants, and requests that
Certificates for such shares shall be issued in the name of

________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
                     (PLEASE TYPE OR PRINT NAME AND ADDRESS)

________________________________________________________________________________
(SOCIAL SECURITY OR TAX IDENTIFICATION NUMBER) and be delivered to

________________________________________________________________________________
(PLEASE PRINT OR TYPE NAME AND ADDRESS)

and, if such number of Warrants shall not be all the Warrants evidenced by this
Warrant Certificate, that a new Warrant Certificate for the balance of such
Warrants be registered in the name of, and delivered to, the Registered Holder
at the address stated below:


Dated:
       ------------------------------   ----------------------------------------
                                        (SIGNATURE)

                                        ----------------------------------------
                                        (ADDRESS)

                                        ----------------------------------------
                                        (TAX IDENTIFICATION NUMBER)


                                        3

<PAGE>

                                   ASSIGNMENT

       To Be Executed by the Registered Holder in Order to Assign Warrants

     For Value Received, _________________________________ hereby sell, assign,
and transfer unto

________________________________________________________________________________
                     (PLEASE TYPE OR PRINT NAME AND ADDRESS)

________________________________________________________________________________
                 (SOCIAL SECURITY OR TAX IDENTIFICATION NUMBER)

____________________ of the Warrants represented by this Warrant Certificate,
and hereby irrevocably constitute and appoint ____________________ attorney to
transfer this Warrant ____________________ Certificate on the books of the
Company, with full power of substitution in the premises.

Dated
       ------------------------------


                                        ----------------------------------------
                                        NOTICE: The signature to this assignment
                                        must correspond with the name as written
                                        upon the face of the certificate in
                                        every particular, without alteration or
                                        enlargement or any change whatever.

Signature(s) Guaranteed:


----------------------------------------------------------------------------
THE SIGNATURE(S) SHOULD BE GUARANTEED BY AN ELIGIBLE GUARANTOR INSTITUTION
(BANKS, STOCKBROKERS, SAVINGS AND LOAN ASSOCIATIONS AND CREDIT UNIONS WITH
MEMBERSHIP IN AN APPROVED SIGNATURE GUARANTEE MEDALLION PROGRAM, PURSUANT TO
S.E.C. RULE 17Ad-15).


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