Wisconsin Power and Light Company Issues $3.3 Million in Credits

Credit issued beginning with bills processed on June 28th

MADISON, Wis., June 29 /PRNewswire-FirstCall/ — Wisconsin Power and Light Company (WPL), an Alliant Energy company (NYSE:LNT) , will issue a credit to its electric customers beginning with bills processed on June 28, 2007. The total credits issued will be approximately $3.3 million.

(Logo: http://www.newscom.com/cgi-bin/prnh/20020405/LNTLOGO )

The refund represents savings from July 2006 through December 2006, and is the result of lower fuel and purchase power costs. Virtually all retail electric customers should expect to receive the credit that will vary based on their usage during this refund period. For a typical residential customer using 600 kilowatt-hours of electricity per month, the refund would be approximately $2.21, including interest.

“The electricity we generate and purchase to meet our customers’ demand comes from a variety of fuel types including coal, nuclear, renewable resources and natural gas,” said Barbara Swan, President-WPL. “We welcome the drop in fuel costs and are pleased we can pass these savings on to our customers.”

The refund complies with the order by the Public Service Commission of Wisconsin (PSCW), from June 8, 2007, which allowed WPL to refund any over-collection of fuel costs for the time period running from July 2006 through December 2006.

Alliant Energy is an energy-services provider with subsidiaries serving approximately 1 million electric and over 400,000 natural gas customers. Providing its customers in the Midwest with regulated electric and natural gas service is the company’s primary focus. Wisconsin Power and Light, the company’s Wisconsin utility subsidiary, serves 453,000 electric and 179,000 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/.

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Source: Alliant Energy

CONTACT: Media, Rob Crain, +1-608-458-4469, or Investor Relations, Becky
Johnson, +1-608-458-3267, both of Alliant Energy

Web site: http://www.alliantenergy.com/