Interstate Power and Light Co. has filed with the Iowa Utilities Board (IUB) its major event report documenting the outages and costs resulting from two major Midwest winter storms in February 2007.

In the report, IPL estimated that restoration costs would be approximately US$70 million. The estimate includes capital costs of approximately $58 million and operation and maintenance costs of approximately $12 million. These costs include labor costs for IPL employees, contract crews, mutual assistance crews from other utilities, poles, conductor wire, supplies and other materials necessary to rebuild the damaged portions of the electric distribution and transmission infrastructure.

IPL does not expect to file a rate case with the IUB in 2007 seeking recovery of costs associated with the restoration and system rebuild efforts. However, the company may address the extraordinary events as part of future rate case proceedings and seek some form of cost recovery. As a result, IPL expects that electric customers' rates should not be affected in 2007 by costs related to the restoration and system rebuild.

Alliant Energy is evaluating the impact that the storm restoration costs and lost revenues will have on its 2007 earnings and planned capital expenditures guidance. This analysis will be updated in conjunction with the first quarter 2007 earnings announcement scheduled for May 4, 2007. The impact of the storm is currently expected to cause 2007 earnings guidance to be in the lower half of Alliant Energy's previously stated guidance range of $2.42 to $2.62 per share, which includes utility earnings guidance of $2.22-$2.42 per share.

IPL completed its initial restoration efforts on March 7, 2007. Permanent repairs to the system continue throughout 2007. More than 269,000 IPL customers lost electric service as a mix of freezing rain, high winds, sleet and snow caused extensive damage to IPL's electric distribution and transmission infrastructure. More than 100 communities served by IPL in Iowa and Minnesota were without electric service for more than 24 hours at some point during the two Midwest winter storms.

More than 2200 IPL employees, mutual assistance and contract employees from utility companies across the country were deployed to assist in the restoration of IPL's electric transmission and distribution infrastructure.

"We're extremely proud of the effort put forth by our employees in restoring power to customers following the ice storm," said Tom Aller, president of IPL. "We also appreciate the patience of our customers during the restoration efforts. We've heard many stories about customers encouraging, feeding and supporting our crews during the storm efforts and we're grateful for the kind and understanding response they provided."