Alliant Energy: Bent Tree Wind Farm begins producing emissions-free energy

Media Contact: Steve Schultz (608) 458-3285

Investor Relations: Susan Gille (608) 458-3956

201 megawatt wind farm in southern Minnesota is now online

MADISON, WI – February 7, 2011 – Wisconsin Power and Light Company (WPL), a subsidiary of Alliant Energy Corporation (NYSE: LNT), has begun commercial operation of the Bent Tree Wind Farm near Albert Lea, in Freeborn County, Minnesota.

The Bent Tree Wind Farm consists of 122 turbines capable of producing up to 201 megawatts of emissions-free wind energy. That’s enough to power approximately 50,000 homes.

“Alliant Energy is committed to providing our customers with balanced energy solutions that are environmentally responsible, reliable and cost effective,” explains John Larsen, President – WPL. “The addition of Bent Tree allows us to meet and exceed Wisconsin’s existing Renewable Portfolio Standard.”

Bent Tree is WPL’s second owned and operated wind farm. Cedar Ridge Wind Farm, a 68 megawatt wind farm in Fond du Lac County, Wisconsin has been in operation since December 2008.

For more information on the Bent Tree Wind Farm, please visit alliantenergy.com/benttree.