USA - Interstate Power and Light Company to expand wind generation potential in Iowa

Interstate Power and Light Company (IPL), a subsidiary of Alliant Energy Corporation announced today that the company has acquired a 300 megawatt wind power farm located in north central Iowa, near Hampton, Iowa from Iowa Winds, LLC. The wind farm is adjacent to a 200 megawatt wind power farm IPL acquired from Wind Capital Group, LLC in November 2007.

The 'Whispering Willow Wind Farm', which consists of the two recent site acquisitions, has the potential to produce up to 500 megawatts of emissions-free energy if completely developed. IPL currently anticipates developing 200 megawatts of wind power on the site beginning in 2009. IPL expects the first 200 megawatts to be commercially operable in 2010. IPL will still have the ability to develop up to an additional 300 megawatts of potential wind power on the site. A decision regarding the development of the wind farm's additional 300 megawatts has not yet been made.

Currently, approximately four percent of IPL's electric energy is derived from wind power. Upon completion of Whispering Willow Wind Farm's initial 200 megawatts, IPL expects that approximately 6 percent of its electricity will be produced from renewable energy sources through either purchased power agreements or company-owned generation. In addition to expanding its renewable energy portfolio, the company is also pursuing needed baseload generation.

About Alliant Energy
Alliant Energy is an energy-services provider with subsidiaries serving approximately 1 million electric and more than 400,000 natural gas customers. Providing its customers in the Midwest with regulated electric and natural gas service is the company's primary focus. Interstate Power and Light, the company's Iowa utility subsidiary, serves 526,000 electric and 232,000 natural gas customers. Alliant Energy, headquartered in Madison, Wis., is a Fortune 1000 company traded on the New York Stock Exchange under the symbol LNT. For more information, visit the company's Web site at http://www.alliantenergy.com.