IPL to Buy Iowa Wind Farm Development, Turbines from Clipper Windpower

100 MW of wind power to come from turbines Clipper builds in Cedar Rapids

Interstate Power and Light Co. (IPL), a subsidiary of Alliant Energy Corporation (NYSE: LNT) announced today that it has entered into negotiations with Clipper Windpower Inc. to purchase the Eclipse wind farm under development in western Iowa. IPL also plans to equip the facility with Clipper’s Liberty-series turbines.

The Eclipse site, located in southern Audubon and Guthrie counties, near Adair, Iowa has the potential to produce as much as 200 megawatts (MW) of clean, wind-generated electricity. IPL plans to file for approval of the Eclipse Wind Farm with the Iowa Utilities Board this summer. Pending regulatory approval, IPL expects to begin construction of the first 100 MW of development in 2009. Commercial operation of the turbines is expected in late 2009.

IPL plans to utilize 2.5 MW Liberty-series turbines, the largest wind turbines built in the United States. Designed and manufactured by Clipper Windpower, the Liberty wind turbines’ key mechanical equipment is assembled at Clipper’s facility in Cedar Rapids.

“This is yet another example of IPL supporting the state’s economy through purchase of products that are assembled right here in Iowa,” explained Tom Aller, president of IPL. “Clipper Windpower is a great company to have here in the state and is part of our state’s growing renewable energy economy. We’re pleased to support Clipper’s Iowa product and employees while doing our part to further Iowa’s role as a renewable energy leader.”

“Iowa’s leadership in supporting its economic development while strengthening its energy sustainability is exemplary and offers a positive model for other states” said James G.P. Dehlsen, Chairman and CEO of California-based Clipper Windpower. “If fully built to a capacity of 200 megawatts, the Eclipse Project would become Iowa’s largest wind energy project. With ‘home-grown’ Liberty wind turbines, the largest built in America, the project will be a showcase for the State.”

Wind generation is an important part of IPL’s overall generation mix. “We continue to seek ways to lessen the environmental footprint of our generation fleet,” explains Kim Zuhlke, vice president of new energy resources for Alliant Energy. “Developing this wind site using some of the most efficient and reliable wind turbines available is a leap forward toward that goal.” Currently, IPL has approximately 260 MW of wind energy under contract in its portfolio.