Wisconsin Power and Light Files Requests to Make Fuel-Cost Adjustments

Adjustments necessary due to actual 2007 fuel costs and projected 2008 fuel costs

MADISON, Wis., March 25 /PRNewswire/ — Wisconsin Power and Light Company (WPL), a subsidiary of Alliant Energy Corporation (NYSE:LNT) , filed requests today with the Public Service Commission of Wisconsin (PSCW) to make a refund based on lower than expected fuel costs for 2007 and to implement a rate adjustment based on projected fuel costs for the remainder of 2008 for electric retail customers.

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Specifically, WPL is requesting approval of a $13.6 million total refund for customers, including interest, due to less-than-expected fuel costs for June 2007 through December 2007. Under WPL’s 2007 fuel refund request, a typical residential customer using 600 kWh of electricity per month would receive a one-time credit of about $8.95.

The proposed refund complies with an agreement reached between WPL and two customer groups, the Citizens Utility Board and the Wisconsin Industrial Energy Group, in which WPL agreed to refund any over-collection of fuel costs for the time period running from June 2007 through December 2007. The PSCW approved the agreement on August 23, 2007.

WPL is also requesting a 2008 interim fuel-only increase of $15.6 million (1.58%) for electric retail customers. This interim fuel-only rate case was filed because actual fuel and purchased power costs through February of this year, combined with projections of continued higher fuel and purchased power costs for the remainder of 2008, significantly exceed the amounts currently recovered in base rates. The same typical residential customer would see a monthly increase of approximately 86 cents on their remaining 2008 electric bills with the requested interim fuel-only rate adjustment.

“While 2007 was a comparatively stable year in terms of fuel costs, which allows WPL to make a refund to our customers, 2008 has unfortunately been and looks to continue to be a different story,” said Barbara Swan, President of WPL. “With fuel and purchased power costs much more volatile in 2008, WPL’s ability to recover these prudent costs in providing reliable electric service in a timely manner ensures fairness to customers and shareowners alike.”

The actual amounts under both requests will vary depending on usage and customer class. The refund and rate adjustment filings must be approved by the PSCW after a review process.

Alliant Energy is an energy-services provider with subsidiaries serving approximately 1 million electric and 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 approximately 450,000 electric and 175,000 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: media, Rob Crain, +1-608-458-4469, or investor relations, Jamie
Freeman, +1-608-458-3274, both of Alliant Energy Corporation

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