Duane Arnold Energy Center Competitive Auction to Include 100% of the

CEDAR RAPIDS, Iowa, Feb. 3 /PRNewswire-FirstCall/ -- Interstate Power and Light Company (IP&L), a subsidiary of Alliant Energy Corporation , Central Iowa Power Cooperative (CIPCO) and Corn Belt Power Cooperative (Corn Belt) have agreed to participate together in a competitive auction process concerning the sale of the Duane Arnold Energy Center (DAEC). As a result of this agreement among the three co-owners, DAEC's competitive auction will include 100 percent of the ownership interests. CIPCO and Corn Belt have 20 percent and 10 percent ownership interests in DAEC, respectively.

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IP&L announced on December 22, 2004 its intent to offer for sale the company's 70 percent ownership interest in the 583-megawatt DAEC, a nuclear generating facility located near Palo, Iowa.

Each co-owner's commitment to divest its DAEC ownership interest is contingent upon the negotiation and approval of an acceptable agreement with a prospective owner. The co-owners plan to enter into an agreement with the winning bidder by June 30, 2005, and will then seek to obtain all appropriate state and federal regulatory approvals. During the approval process, CIPCO and Corn Belt, as borrowers from the United States Department of Agriculture's (USDA) Rural Utilities Service (RUS), will need to obtain approval from the RUS for the sale of their DAEC ownership interests.

Concentric Energy Advisors (CEA) has been retained by the three co-owners to serve as the auction manager and financial advisor for the sale of DAEC. CEA will provide strategic support throughout the transaction and regulatory approval process. DAEC is one of the few nuclear generating facilities operated by a third party to be auctioned in the United States. The Nuclear Management Company (NMC) currently operates the DAEC, which affords qualified parties not currently licensed by the Nuclear Regulatory Commission (NRC) as nuclear operators the opportunity to participate in the auction.

Interested prospective purchasers should contact John J. Reed of CEA to register their interest in participating in the transaction and obtain qualifications criteria. Mr. Reed can be contacted by phone, (508) 263-6262, mailing address, Concentric Energy Advisors, 313 Boston Post Road West, Suite 210, Marlborough, Massachusetts 01752, e-mail DAEC@ceadvisors.com .

"The DAEC competitive auction process presents an important opportunity for prospective buyers and our customers," states Tom Aller, President-IP&L. "Our company is pleased that CIPCO and Corn Belt will partner with IP&L in the auction process. We expect that the potential for a buyer to acquire 100 percent ownership of the generating facility with the opportunity to secure long-term power purchase agreements with the original owners will be attractive to a number of parties. We also see this transaction as providing the opportunity to reduce financial and operational uncertainty for our customers and shareowners."

"CIPCO's Board of Directors and members are optimistic about the opportunities of a successful auction process of the DAEC with IP&L. Although each of the three owners has unique needs relative to the consummation of a successful transaction, this offering will establish the market value of this resource. By taking advantage of this process, it allows CIPCO the chance to reevaluate our long-term power supply portfolio and may offer a viable opportunity to further optimize our generation mix," stated Dennis Murdock, Executive Vice President and CEO.

"By participating in the process, Corn Belt will keep abreast of the options open for its share of the Duane Arnold Energy Center, which will ultimately hold down costs for our member cooperatives," explains Dale Arends, Executive Vice President and General Manager, Corn Belt.

About Alliant Energy

Alliant Energy Corporation is an energy-services provider with subsidiaries serving more than three million customers. Providing its customers in the Midwest with regulated electricity and natural gas service remains the company's primary focus. Interstate Power and Light Company, the company's Iowa utility subsidiary, serves 529,000 electric and 236,000 natural gas customers. Other business platforms include the international energy market and non-regulated domestic generation. Alliant Energy Corporation, 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/ .

About Central Iowa Power Cooperative

Central Iowa Power Cooperative (CIPCO) is a consumer-owned, not-for-profit electric cooperative that generates and transmits power to our member owners -- 12 rural electric cooperatives and one municipal electric cooperative-all located within the state of Iowa. CIPCO's members collectively serve a population of more than 260,000 rural and urban Iowans located in 58 of Iowa's 99 counties. This service territory stretches 300 miles diagonally across Iowa and includes or adjoins 12 of Iowa's 17 cities with populations greater than 25,000. CIPCO is headquartered in Cedar Rapids, Iowa with locations in Wilton, Montpelier, Creston and Des Moines. For additional information, visit the cooperative's web site at http://www.cipco.net/ .

About Corn Belt Power Cooperative

Corn Belt Power Cooperative, headquartered in Humboldt, Iowa, is a generation and transmission cooperative that provides electricity to 11 rural electric cooperatives (RECs) and one municipal electric cooperative. These utilities provide power to farms, rural residences, small towns and commercial/industrial customers in 28 northern Iowa counties. For more information, visit the cooperative's web site at http://www.cbpower.com/ .

About Concentric Energy Advisors

Concentric Energy Advisors ( http://www.ceadvisors.com/ ) is a privately owned financial advisory and consulting firm focused on the North American energy and water utilities industry. Based in Marlborough, Massachusetts, CEA specializes in M&A and other transaction-related financial advisory services, strategic market assessments, litigation and regulatory support, and utility ratemaking services and expert testimony.