Alliant Energy: Hosts annual meeting of shareowners in Madison

Media Contact: Scott Reigstad (608) 458-3145

Investor Relations: Susan Gille (608) 458-3956

CEO reflects on challenging times and looks optimistically to the future

MADISON, WI – May 20, 2010 – Alliant Energy Corporation (NYSE: LNT) Chairman, President and CEO Bill Harvey reflected on challenges faced during the past three years, while also stressing the strong financial position moving forward for the company as he addressed the 2010 Annual Meeting of Shareowners today at the Alliant Energy Center in Madison.

“2009 was an extraordinary year for our economy, our country and your company,” Harvey told shareowners. “Despite the ice storms of 2007, the floods of 2008 and the economic calamity of 2009, I am pleased to report that your company has not only endured but also emerged stronger, healthier and quite optimistic about its future.” He later added that, “You should expect balance in what we do and an above average total return on what you have invested. We will continue our balanced approach to meeting the needs of our customers.”

Harvey also discussed the aggressive measures taken by the company to reduce costs as well as the strong customer satisfaction performance by Alliant Energy in 2009. “We took aggressive measures to dampen the negative impact on our earnings as well as on our customers’ rates. We froze salaries in 2009; took a week off without pay and experienced cuts in company contributions to retirement programs, and we restructured the size of our workforce,” he explained. Harvey noted that “In 2009 we both experienced – and accomplished – a lot and that has been recognized by our customers who said we did an above average job of providing utility service by ranking us 5th in the Midwest Regional J.D. Power survey of electric utilities of our size.”

He further noted the company’s ongoing environmental commitment. “During the year we made great progress in the permitting and construction of new, state-of-the-art environmental controls at some of our largest most efficient coal plants. These investments are expected to result in significant emissions reductions and make improvement to the environment we all live in here in the Midwest,” Harvey said.

Harvey also elaborated on the investments Alliant Energy’s utilities have made in renewable energy, highlighting the 200-megawatt Whispering Willow East Wind Farm in Iowa that was commissioned in December 2009 and the recent start of construction of the 200-megawatt Bent Tree Wind Farm in Minnesota. When the Bent Tree Wind Farm becomes fully-operational, wind energy will make up about 11 percent of Alliant Energy’s overall generation portfolio. The company continues on a path to a greener and smarter energy future, according to Harvey.

Alliant Energy’s commitment to the environment extends beyond emission reduction projects and renewable energy and also includes energy efficiency initiatives and implementation of Smart Grid efforts. The company plans to provide additional tools to customers to empower them to use energy wisely and save money on their energy bills. In addition to the deployment of smart meters, Alliant Energy plans to spend several hundred million dollars on energy efficiency throughout its service territory to continue its commitment to conservation and energy efficiency over the next five years.

Alliant Energy Corporation is an energy-services provider with subsidiaries serving approximately 1 million electric and over 412,000 natural gas customers. Providing its customers in the Midwest with regulated electric and natural gas service is the company’s primary focus. 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.

This press release contains forward-looking statements. These forward-looking statements can be identified as such because the statements include words such as “expected,” or other words of similar import. Similarly, statements that describe future plans or strategies are also forward-looking statements. Such statements are subject to certain risks and uncertainties that could cause actual results to differ materially from those currently anticipated. Actual results could be affected by such factors as: state or federal regulatory actions or local government actions, unanticipated construction issues, delays or expenditures; current or future litigation, regulatory investigations, proceedings or inquiries that could impede the implementation of Alliant Energy’s plans; and failure of equipment and technology to perform as expected. These factors should be considered when evaluating the forward-looking statements and undue reliance should not be placed on such statements. The forward-looking statements included herein are made as of the date hereof and Alliant Energy undertakes no obligation to update publicly such statements to reflect subsequent events or circumstances.