Exhibit 21 Subsidiaries of the Registrants

Name of Company	Jurisdiction of Incorporation  or Organization
Pepco Holdings, Inc.	DE
Potomac Electric Power Company	DC and VA
POM Holdings, Inc.	DE
Pepco Energy Services, Inc.	DE
Conectiv Thermal Systems, Inc. (d/b/a Pepco Energy Services)	DE
ATS Operating Services, Inc.	DE
Atlantic Jersey Thermal Systems, Inc.	DE
Thermal Energy Limited Partnership I	DE
Eastern Landfill Gas, LLC	DE
Blue Ridge Renewable Energy, LLC	DE
Distributed Generation Partners, LLC	DE
Rolling Hills Landfill Gas, LLC	DE
Potomac Power Resources, LLC	DE
Fauquier Landfill Gas, L.L.C.	DE
Pepco Energy Services - Suez Thermal, LLC	DC
Pepco Government Services LLC	DE
Pepco Enterprises, Inc.	DE
Pepco Energy Cogeneration LLC	DE
Bethlehem Renewable Energy, LLC	DE
Pepco Building Services Inc.	MD
W.A. Chester, L.L.C.	DE
W.A. Chester Corporation	DE
Chester Transmission Construction Canada, Inc.	Canada
Severn Construction Services, LLC	DE
Chesapeake HVAC, Inc. (f/k/a Unitemp, Inc.)	DE
Pepco Energy Solutions, LLC	DE
Potomac Capital Investment Corporation	DE
PCI Netherlands Corporation	NV
PCI Queensland, L.L.C.	NV
AMP Funding, L.L.C.	DE
RAMP Investments, L.L.C.	DE
PCI Air Management Partners, L.L.C.	DE
PCI Ever, Inc.	DE
Friendly Skies, Inc.	Virgin Islands
PCI Air Management Corporation, a Nevada Corporation	NV
Potomac Nevada Investment Inc., a Nevada Corporation	NV
American Energy Corporation	DE
PCI-BT Investing, L.L.C.	DE
Linpro Harmans Land LTD Partnership	MD
PCI Energy Corporation	DE
Potomac Nevada Corporation	NV
Potomac Nevada Leasing Corporation	NV
Potomac Delaware Leasing Corporation	DE
Potomac Equipment Leasing Corporation	NV
Potomac Leasing Associates, LP	NV
Potomac Capital Joint Leasing Corporation	DE

362

PCI Nevada Investments	DE
PCI Holdings, Inc.	DE
Aircraft International Management Company	DE
PCI Engine Trading Ltd.	Bermuda
PHI Service Company	DE
Conectiv, LLC	DE
Delmarva Power & Light Company d/b/a Delmarva Power	DE and VA
Atlantic City Electric Company d/b/a Atlantic City Electric	NJ
Atlantic City Electric Transition Funding LLC	DE
Conectiv Properties and Investments, Inc.	DE
Conectiv Solutions LLC	DE
ATE Investment, Inc.	DE
Enertech Capital Partners, LP	DE
Enertech Capital Partners II, LP	DE
Blacklight Power, Inc.	DE
Millennium Account Services, LLC	DE
Conectiv Services, Inc.	DE
Atlantic Generation, Inc.	NJ
Vineland Ltd., Inc.	DE
Vineland Cogeneration Limited Partnership	DE
Vineland General, Inc.	DE
Conectiv Communications, Inc.	DE
Atlantic Southern Properties, Inc.	NJ
Conectiv Energy Supply, Inc.	DE
Conectiv North East, LLC	DE
Energy Systems North East, LLC	DE
Delaware Operating Services Company, LLC	DE
Tech Leaders II, L.P.	DE

363