 Exelon subsidiary PECO Energy Company, founded as the Brush Electric Light Company of Philadelphia in 1881 and renamed Philadelphia Electric Company (PECO) in 1902, provides electricity to about 1.6 million customers and more than 500,000 natural gas customers in the southeastern Pennsylvania area including the city of Philadelphia and most of its suburbs.PECO is the largest electric and natural gas utility in the state with 472 power substations and nearly of electric transmission and distribution lines, along with of natural gas transmission, distribution & service lines.Philadelphia Gas Works (PGW), overseen by the Pennsylvania Public Utility Commission, is the nation's largest municipally-owned natural gas utility.