5. Xcel Energy, 390,056 MWh/year
Minneapolis-based utility company Xcel Energy was listed as the No. 1 utility provider of wind energy by the American Wind Energy Association (AWEA), with nearly 5 GW of wind power capacity. Since 1998, Xcel Energy's Windsource program has allowed customers to designate that part or all of their electricity comes from a renewable energy source. In 2011, about 58,000 people were enrolled in Windsource.