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                                                                     EXHIBIT 5.1

                         STROOCK & STROOCK & LAVAN LLP
                                180 Maiden Lane
                            New York, New York 10038


September 28, 2000

Orion Power Holdings, Inc.
7 East Redwood Street, 10th Floor
Baltimore, Maryland 21202

Ladies and Gentlemen:

We have acted as counsel to Orion Power Holdings, Inc., a Delaware corporation
(the "Company"), in connection with the preparation and filing with the
Securities and Exchange Commission (the "Commission") under the Securities Act
of 1933, as amended (the "Act"), of a Registration Statement on Form S-1
(Registration No. 333-44118), as amended (the "Registration Statement"),
relating to the proposed public offering (the "Offering") by the Company of up
to 21,779,032 shares of its common stock, par value  $.01 per share (the
"Common Stock"), and by the selling stockholders named in the Registration
Statement (the "Selling Stockholders") of up to 3,220,968 shares of Common
Stock (all such shares of Common Stock being hereinafter collectively referred
to as the "Shares").

As such counsel, we have examined copies of the Certificate of Incorporation
and By-Laws of the Company, each as amended to the date hereof, the
Registration Statement, the Prospectus which forms a part of the Registration
Statement and originals or copies of such corporate minutes, records,
agreements and other instruments of the Company, certificates of public
officials and other documents, and have made such examinations of law, as we
have deemed necessary to form the basis for the opinion hereinafter expressed.
In our examination of such materials, we are assumed the genuineness of all
signatures, the authenticity of all documents submitted to us as originals and
the conformity to original documents of all copies submitted to us. As to
various questions of fact material to such opinion, we have relied, to the
extent we deemed appropriate, upon representations, statements and certificates
of officers and representatives of the Company and others.

Attorneys involved in the preparation of this opinion are admitted to practice
law in the State of New York and we do not purport to express any opinion herein
concerning any law other than the laws of the State of New York, the federal
laws of the United States of
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September 28, 2000
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America and the General Corporation Law of the State of Delaware.


Based upon and subject to the foregoing, we are of the opinion that (i) the
Shares being offered by the Company, when and if issued and sold under the
circumstances contemplated by the Registration Statement, will be legally
issued, fully paid and non-assessable and (ii) the Shares being offered by the
Selling Stockholders, when and if sold under the circumstances contemplated by
the Registration Statement, will be legally issued, fully paid and
non-assessable.

We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and to the reference to this firm under the caption
"Legal Matters" in the Prospectus which forms a part of the Registration
Statement. In giving such consent, we do not admit hereby that we come within
the category of persons whose consent is required under Section 7 of the Act or
the Rules and Regulations of the Commission thereunder.


Very truly yours,

/s/ STROOCK & STROOCK & LAVAN LLP

STROOCK & STROOCK & LAVAN LLP