Alliant Energy: Releases annual Environmental Report

Media Contact: Steve Schultz (608) 458-3285

Investor Relations: Susan Trapp Gille (608) 458-3956

Strategic plan continues to balance efficiency, energy and the environment

MADISON, WI — Alliant Energy Corporation (NYSE: LNT) has released its annual Environmental Report highlighting the company’s environmental performance over the last year, as well as its energy efficiency programs, the status of the company’s plans to upgrade its generation fleet and expand its renewable energy portfolio.

The report is broken down into four sections emphasizing the company’s environmental commitment, its approach to environmental management and oversight, its performance on various environmental-related metrics and it describes the company’s future efforts to reduce environmental impacts.

“We are proud of the work our company has done to preserve the high quality of our Midwestern air, water and land resources,” said Bill Harvey, Chairman, President and Chief Executive Officer, Alliant Energy. “While that work is embodied in a larger sense by our strong commitment to renewable energy, it begins on a more local scale through our efforts to make our facilities greener. As we continue to look for greener sources to provide reliable and affordable energy, we are also adding to our already-strong lineup of energy efficiency programs.”

Other key information in the report includes:

* An update on our Clean Air Compliance Program progress, including the installation of emissions controls at Lansing Generating Station in Lansing, IA.

* The expansion of our renewable portfolio. By the end of 2011, IPL and WPL will have invested more than $1 billion in company owned and operated wind energy.

* Laying the foundation for Smart Grid through the continued installation and retrofitting of more than 1.4 million electric and natural gas meters with Advanced Metering Infrastructure (AMI) technology to help educate customers about their energy usage behavior.

“I am grateful to our dedicated employees whose every day actions demonstrate our commitment to preserve and protect our invaluable natural resources,” said Kathy Lipp, Chief Environmental Officer, Alliant Energy.

You can access an electronic copy of Alliant Energy’s annual Environmental Report by visiting http://www.alliantenergy.com/environment.

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. 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.