Duke Energy Florida, LLC

Sometimes the sunshine state just isn't bright enough, and that's when Florida Power (doing business as Progress Energy Florida) really shines. The utility transmits and distributes electricity to 1.6 million customers and oversees 10,025 MW of generating capacity from interests in 14 nuclear and coal-, oil-, and gas-fired power plants. Additionally, Florida Power purchases about 20% of the energy it provides. Florida Power operates 5,100 miles of transmission lines and 52,000 miles of overhead and 18,700 miles of underground distribution cable. It also has 500 electric substations. A subsidiary of holding company Duke Energy, the company also sells wholesale power to other utilities and marketers.