Commonwealth Edison Company

Commonwealth Edison Company (ComEd) is the largest electric utility in Illinois and serves more than 4 million customers across northern Illinois—including Chicago—covering about 70% of the state’s population. Founded in 1907 as part of Thomas Edison's enterprises, ComEd has evolved into a subsidiary of Exelon Corporation. While its core business is electricity delivery—not generation—it has become a key enabler of clean energy transition efforts throughout its service territory.
In recent years ComEd has invested heavily in grid modernization—including one of the nation’s largest Smart Grid programs—and supports over 1 GW of interconnected distributed energy resources such as rooftop and commercial-scale solar systems along with more than 150 active community solar sites serving over 30,000 subscribers by early 2025. Through partnerships like those with Ameresco on landfill-to-solar conversions or DOE-backed pilots integrating battery storage with renewables at scale, ComEd helps facilitate access to renewable power even for those unable to install their own panels.
The company also administers customer-facing programs that allow residents and businesses to subscribe to local community solar arrays—earning bill credits based on their share—thus broadening access beyond traditional ownership models. With ongoing commitments under state policies like CEJA aiming for at least 40% renewables by 2030 statewide—and projected growth toward nearly double today’s DER capacity by decade's end—ComEd remains central to Illinois’ clean energy future while maintaining reliable service across one of America’s most populous regions.