Alliant Energy: Wisconsin Power and Light closes on purchase of Edgewater Generating Station Unit 5

Media Contact: Scott Reigstad (608) 458-3145

Investor Relations: Susan Gille (608) 458-3956

Madison, Wis. – March 1, 2011 – Wisconsin Power and Light Company (WPL), a subsidiary of Alliant Energy Corporation (NYSE:LNT), has closed on the purchase of Wisconsin Electric Power Company’s (WEPCo’s) 25 percent ownership interest of the Edgewater Generating Station Unit 5 in Sheboygan, Wis. WPL now owns 100 percent of Edgewater Generating Station Unit 5.

“Edgewater Unit 5 is the newest baseload generating station in our fleet, and it will provide our customers with a reliable and efficient source of energy for many years to come,” said John Larsen, WPL President. “We believe that complete ownership of Unit 5, along with the emission controls we are installing at the facility, gives us additional flexibility for the future that will benefit our customers, shareowners and company.”

The closing price was approximately $38 million, which is the net book value of WEPCo’s share of the plant and related working capital.

The Edgewater Generating Station includes three generating units with a total nameplate capacity of 770 megawatts. Unit 3 is a 60-megawatt nameplate capacity unit that was placed in service in 1951; Unit 4 is a 330-megawatts nameplate capacity unit that was placed in service in 1969; and Unit 5 is a 380-megawatt nameplate capacity unit that was placed in service in 1985. WPL’s purchase of full ownership interest in Edgewater Generating Station Unit 5 adds about 95 megawatts to its generating portfolio.