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                                                                     EXHIBIT 8.1

                               [FORM OF SABW OPINION]
                                 [SABW LETTERHEAD]


                                   ________, 2005

Exelon Corporation
10 South Dearborn Street
37th Floor
Chicago, Illinois 60680-5379

     Re:  REGISTRATION STATEMENT ON FORM S-4

Ladies and Gentlemen:

     We have acted as counsel for Exelon Corporation, a Pennsylvania
corporation ("Parent"), in connection with (i) the merger (the "Merger"),
contemplated by, and defined and described in, the Agreement and Plan of
Merger (the "Agreement") dated as of December 20, 2004, between Parent and
Public Service Enterprise Group Incorporated, a New Jersey corporation (the
"Company"), and (ii) the preparation and filing of the related Registration
Statement on Form S-4, which includes a joint proxy statement and prospectus
(as amended through the date hereof, the "Registration Statement"), filed
with the Securities and Exchange Commission (the "Commission").  You have
requested our opinion regarding certain United States federal income tax
consequences of the Merger.  Unless otherwise indicated, each capitalized
term used but not defined herein has the meaning ascribed to it in the
Agreement.

     In connection with this opinion letter, we have examined the Agreement,
the Registration Statement and such other documents as we have deemed
necessary or appropriate in order to enable us to render our opinions,
including, but not limited to, certain representation letters received by us
from each of Parent and the Company dated the date hereof and referring to
this opinion letter (the "Representation Letters").

     Further, for purposes of rendering this opinion letter, we have made the
following assumptions:  (i) original documents submitted to us (including
signatures) are authentic, documents submitted to us as copies conform to the
original documents and all such documents either have been or will be, by the
Effective Time, duly and validly executed and delivered where such execution
and delivery are prerequisites to effectiveness; (ii) the Merger will qualify
as a statutory merger under the laws of New Jersey and Pennsylvania and will
be effected in the manner described in the Registration Statement and in
accordance with the provisions of the Agreement; (iii) the statements
concerning the Merger set forth in the Registration Statement, including the
purposes of the Company and Parent for consummating the Merger, are accurate
and complete; (iv) the representations set forth in the Agreement are
accurate and complete at all relevant times; (v) the statements and
representations of the Company and Parent set forth in their respective
Representation Letters are accurate and complete at the time given and will
be accurate and complete at all times through the Effective Time; (vi) the
covenants and agreements contained in the Agreement and the Representation
Letters will be performed without waiver or

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Exelon Corporation
_______, 2005
Page 2


breach of any material provision; (vii) any statement or representation
referred to in clause (iv) or (v) above that (A) is qualified by knowledge
(or similarly qualified) is correct without such qualification or (B) relates
to the absence of any plan, intention, understanding or agreement signifies
that there is in fact no plan, intention, understanding or agreement and
(viii) the Merger will be reported by Parent and the Company on their
respective United States federal income tax returns in a manner consistent
with the opinions set forth below.

     Our opinions are not binding on the IRS.  Our opinions are based on the
Internal Revenue Code of 1986, as amended (the "Internal Revenue Code"),
applicable United States Treasury regulations, administrative interpretations
and court decisions, each as in effect as of the date hereof and all of which
are subject to change possibly with retroactive effect.  A change in any of
the foregoing or the inaccuracy of any of the documents or assumptions on
which our opinions are based could affect our conclusions.

     Based upon and subject to the foregoing, in our opinion:

     (i)   the Merger will be treated for United States federal income tax
purposes as a reorganization within the meaning of Section 368(a) of the
Internal Revenue Code; and

     (ii)  each of Parent and the Company will be a party to the
reorganization within the meaning of Section 368(b) of the Internal Revenue
Code.

     Based upon and subject to the foregoing, in our opinion the statements
set forth in the Registration Statement under the heading "Material United
States Federal Income Tax Consequences of the Merger", to the extent they
constitute matters of United States federal income tax law or legal
conclusions with respect thereto, are correct in all material respects.

     Our opinions are limited to the tax matters specifically covered hereby,
and we have not been asked to address, nor have we addressed, any other tax
consequences of the Merger or any other transactions.  We disclaim any
undertaking to advise you of any subsequent changes of the matters stated,
represented or assumed herein or any subsequent changes in applicable law,
regulations or interpretations thereof.

     We hereby consent to the reference to this opinion letter in the
Registration Statement, to the filing of this opinion letter as an exhibit to
the Registration Statement and to the reference to our firm under the
headings "Summary--PSEG Shareholders Will Not Recognize Any Gain or Loss for
United States Federal Income Tax Purposes Upon the Exchange of Their Shares
of PSEG Common Stock, Except that Gain or Loss Will be Recognized on the
Receipt of Cash in Lieu of a Fractional Share of Exelon Common Stock" and
"Material United States Federal Income Tax Consequences of the Merger" in the
Registration Statement.  In giving such consent, we do not thereby admit that
we are in the category of persons whose consent is required under Section 7
of the Securities Act of 1933, as amended, or the rules and regulations of
the Commission thereunder.

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Exelon Corporation
_______, 2005
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     We are furnishing this opinion letter to you solely in connection with
the filing of the Registration Statement.

                                       Very truly yours,