PECO Energy Company primarily engages in the purchase and regulated retail sale of electricity, and the provision of transmission and distribution services to residential, commercial, and industrial customers in southeastern Pennsylvania, including the City of Philadelphia. It also engages in the purchase and regulated retail sale of natural gas, and the provision of distribution services in the Pennsylvania counties surrounding the City of Philadelphia. As of December 31, 2007, the company delivered electricity to approximately 1.6 million customers and natural gas to approximately 480,000 customers. PECO Energy’s electric distribution system comprised 12,933 circuit miles of overhead lines and 15,260 cable miles of underground lines. It also operated 12,157 natural gas pipeline miles for transportation, distribution, and service piping. The company was incorporated in 1929 and is based in Philadelphia, Pennsylvania. PECO Energy Company is a subsidiary of Exelon Corporation.