The Chicago-based utility has 20-year agreements to buy power from four wind farms in Pennsylvania and West Virginia. The wind farms together produce enough electricity to power about 105,000 homes. Exelon is entering its fifth year in the wind energy business, and its 154 megawatts is enough to power 40,000 homes.

Exelon distributes electricity to 5.2 million customers in northern Illinois and Pennsylvania and generates $14 billion in annual revenue.