Alliant Energy closes on sale of Australian assets to Meridian Energy Ltd.

MADISON, Wis., May 2, 2003 — Alliant Energy Corp. has closed on the sale of its Australian assets to New Zealand-based Meridian Energy Limited.

The sale price was approximately $365 million. This sale will provide for the repayment of approximately $150 million in debt in Australia. On an after-tax basis, the sale resulted in net cash proceeds to Alliant Energy of approximately $170 million and provides the company with approximately $320 million to be applied toward debt reduction.

Alliant Energy’s Australian assets were principally made up of Southern Hydro’s ten hydroelectric generating stations in the state of Victoria in southeast Australia. Southern Hydro’s total generating capacity is 540 megawatts.

“This is the first of our four planned divestitures of non-regulated businesses to close and we look forward to successfully closing the other three as the year progresses,” said Erroll B. Davis, Jr., chairman, president and CEO of Alliant Energy. “We continue to make progress in successfully executing the steps we announced last November and are committed to seeing this comprehensive plan through to completion.”

In addition to its Australian investments, Alliant Energy previously announced its intention to exit its affordable housing business, primarily consisting of Heartland Properties, Inc; Whiting Petroleum Corporation, its oil and gas business; and SmartEnergy, Inc.™, an electric and gas retailer principally operating in New York City.

Alliant Energy is an energy-services provider that serves more than three million customers worldwide. Providing its regulated customers in the Midwest with electricity and natural gas service remains the company’s primary focus. Other key business platforms include the international energy market and non-regulated domestic generation. 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 www.alliantenergy.com .