Wisconsin Power and Light Company Receives Order on Rate Case Reopening

Reopening Request Reflected Customer Credits That Will Discontinue at the End of 2007

MADISON, Wis., Nov. 30 /PRNewswire-FirstCall/ — Wisconsin Power and Light Company (WPL), a subsidiary of Alliant Energy Corporation (NYSE:LNT) , yesterday received an order from the Wisconsin Public Service Commission (PSCW) approving its request to reopen its 2006 general rate case due to the discontinuation of electric customer credits.

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The PSCW order authorized an electric rate increase of $25.8 million for WPL to reflect the customer credits that will discontinue at the end of 2007. The new electric rates are to be effective January 1, 2008. No incremental change in natural gas rates was requested. The order also allows WPL to accrue AFUDC at authorized rates on 100 percent of retail CWIP balances that exceed the $23.7 million of retail electric CWIP established in the PSCW final decision of January 19, 2007.

On April 17, 2007, WPL requested that the PSCW reopen its 2006 retail electric and natural gas rate case (Docket No. 6680-UR-115) due to the expiration of several credits that will be fully returned to customers by the end of the year. Currently included as credits in WPL electric customers’ rates are the return of decommissioning funds from the sale of the Kewaunee Nuclear Power Plant, tax benefits from the American Jobs Creation Act of 2004, and savings from the company’s workforce reduction in 2005, among other credits.

WPL filed to reopen its general rate case because, with the exception of discontinuing the credits, the company does not anticipate filing a retail electric or natural gas case that will change base rates in 2008.

Alliant Energy is an energy-services provider with subsidiaries serving approximately 1 million electric and over 420,000 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 459,000 electric and 182,000 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 Corporation

CONTACT: Rob Crain, +1-608-458-4469, or investor relations, Becky
Johnson, +1-608-458-3267, both for Alliant Energy Corporation

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