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FOR IMMEDIATE RELEASE:                                                CONTACTS:
October 2, 2000                                                     News Media:
                                                                    -----------
                                             Michael J. McGarry  (703) 561-6063
                                                           Financial Community:
                                                           -------------------
                                               Thomas L. Hughes  (703) 561-6001

COLUMBIA ENERGY GROUP SELLS POWER GENERATION SUBSIDIARY TO ORION POWER HOLDINGS

         HERNDON, Va., October 2, 2000 - Columbia Energy Group announced today
that it has agreed to sell Columbia Electric Corporation, a wholly owned
subsidiary, to Orion Power Holdings for approximately $200 million. The sale
does not include Columbia's membership interests in four Qualifying Facilities
located in Texas, New Jersey, and Maine. Columbia Electric develops and operates
natural gas fueled power generation facilities.

         The sale of Columbia Electric includes two power generation facilities
currently under construction. Those projects are The Liberty Electric Project,
an approximately 568 megawatt (MW) facility located in Eddystone, Pa., and the
Ceredo Electric Generation Station, an approximately 500 MW peaking project
located in Wayne County, W. Va. Also included are several projects in various
stages of development in both the ECAR and PJM regions. ECAR and PJM are major
regional electrical grids.

         The transaction, subject to approval under the Hart-Scott-Rodino Act
and other conditions, is expected to close by mid-December 2000. Morgan Stanley
Dean Witter advised Columbia Energy Group on the transaction.

         Columbia Energy Group, based in Herndon, Va., is one of the nation's
leading energy services companies, with assets of approximately $7 billion. Its
operating companies engage in nearly all phases of the natural gas business,
including exploration and production, transmission, storage and distribution,
propane and petroleum product sales, and electric power generation. Information
about Columbia Energy Group (NYSE:CG) is available on the Internet at
www.columbiaenergygroup.com.

         Orion Power Holdings, Inc., based in Baltimore, Maryland, is an
independent electric power generating company formed in March 1998 to acquire,
develop, own and operate power-generating facilities in the newly deregulated
wholesale markets throughout the United States and Canada. Since its inception,
Orion Power Holdings has invested more than $3 billion in 81 power plants with a
total capacity of 5,396 megawatts.

This press release contains "forward-looking statements" within the meaning of
the Federal securities laws, including statements concerning Columbia's,
Columbia Electric's, and Orion Power's plans, objectives and expected
performance. There can be no assurance that actual results will not differ
materially due to various factors, many of which are beyond the control of the
companies, including, but not limited to, market conditions and competition.



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