Delmarva Power and Light Company is a regulated energy company that provides electricity and natural gas services to customers in the Delmarva Peninsula. The company was founded in 1909 as Delaware Power & Light; however, its beginnings can be traced to the 1880s when a number of small power companies sprang up to provide electric service to the Delmarva Peninsula. These companies continued appearing over the next two decades, including Wilmington City Electric, Delaware Electric Company, Tasley Ice Company, the Phoenix Company, and Wilmington Light and Telephone Company. All of these small providers had either folded or consolidated by 1928 into two large companies. The remaining companies were Delaware Power and Light, headquartered in Wilmington, and Eastern Shore Gas and Electric, which controlled power on the lower Delmarva Peninsula. The two companies merged in 1943. In 1966, the utility changed its name to Delmarva Power and Light.

Conectiv, Inc. is a holding company formed in 1998 by the merger of Atlantic Electric Incorporated and Delmarva Power and Light Company, two large regional power utilities that supplied Southern New Jersey and the Delmarva Peninsula. In 2002, Potomac Electric Power Company (Pepco) acquired Conectiv, Inc. and created Pepco Holdings, Inc., a holding company that owned both Conectiv and Delmarva Power.

Today, Delmarva Power and Pepco are subsidiaries of the Exelon Company, and Conectiv Energy is a subsidiary of the Calpine Corporation.