Exhibit F


                       [Letterhead of Gary D. Benz, Esq.]


                                December 18, 2003



Securities and Exchange Commission
450 Fifth Street, N.W.
Washington, D.C. 20549


     Re:  FirstEnergy Corp. -
          Application/Declaration on Form U-1 (File No.70-10138)

Dear Sirs:

     I refer to the Form U-1 Application/Declaration in the above-referenced
proceeding (the "Application") under the Public Utility Holding Company Act of
1935, as amended (the "Act"), filed with the Securities and Exchange Commission
(the "Commission") by FirstEnergy Corp. ("FirstEnergy"), an Ohio corporation,
and to the Commission's order dated November 10, 2003 approving the Application
(Holding Co. Act Release No. 27756) (the "Order"). Capitalized terms used in
this letter without definition have the meanings ascribed to such terms in the
Application.

     In the Application, FirstEnergy requested Commission authorization under
the Act to acquire, directly or indirectly through one or more subsidiary
companies, a membership interest in PowerTree Carbon Company, LLC ("PowerTree"),
a Delaware limited liability company, and, to the extent such approval is
necessary, to transfer all or a portion of such membership interest to any
associate company. In accordance with the terms of the Application and the
Order, FirstEnergy, through its indirect wholly-owned subsidiary, FirstEnergy
Generation Corp. ("GenCo"), has executed the Operating Agreement and made its
initial capital contribution to PowerTree.

     I have acted as counsel for FirstEnergy in connection with the Application
and, as such counsel, I am familiar with the corporate proceedings taken by
FirstEnergy in connection with the proposed transaction, as described in the
Application. I have examined originals, or copies certified to my satisfaction,
of such corporate records of FirstEnergy, certificates of public officials,
certificates of officers and representatives of FirstEnergy, and other documents
as I have deemed it necessary to examine as a basis for the opinions hereinafter
expressed. In such examination, I have assumed the genuineness of all signatures
and the authenticity of all documents submitted to me as originals and the
conformity with the originals of all documents submitted to me as copies. As to
various questions of fact material to such opinions, I have, when relevant facts
were not independently established, relied upon certificates of officers of





FirstEnergy and other appropriate persons and statements contained in the
Application and the exhibits thereto.

     Subject to the foregoing, I am of the opinion that:

     (a)  all state laws applicable to the proposed transaction have been
          complied with;

     (b)  (i) PowerTree is validly organized and duly existing under the laws of
          Delaware, and (ii) GenCo is entitled to all of the rights and
          privileges of a member of PowerTree as set forth in PowerTree's
          Operating Agreement;

     (c)  GenCo has legally acquired a membership interest in PowerTree; and

     (d)  the consummation of the proposed transaction has not violated the
          legal rights of the holders of any securities issued by FirstEnergy or
          any associate company thereof.

     I am an attorney licensed to practice in the State of Ohio and Commonwealth
of Pennsylvania and have acted as counsel to FirstEnergy in connection with the
proposed transaction. For purposes of this opinion, with respect to all matters
governed by the laws of Delaware as applicable to PowerTree, I have relied upon
an opinion addressed to FirstEnergy of Morris, James, Hitchens & Williams LLP,
Wilmington, Delaware, which opinion was filed as an exhibit to the Application.

     I hereby give my written consent to the use of this opinion in connection
with the filing of a certificate pursuant to Rule 24 in the above-referenced
proceeding. This opinion is intended solely for the use of the Commission and
may not be relied upon by any other person for any other purpose.



                                             Very truly yours,


                                             /s/ Gary D. Benz
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