Alliant Energy: Receives go ahead for environmental controls project to further reduce air emissions from Columbia Energy Center

Media Contact: Steve Schultz (608) 458-3285

Investor Relations: Susan Gille (608) 458-3956

Estimated $627 million project designed to reduce mercury and sulfur dioxide emissions

MADISON, WI – February 24, 2011 – Wisconsin Power and Light Company (WPL), a subsidiary of Alliant Energy Corporation (NYSE: LNT), along with co-owners Wisconsin Public Service Corporation (WPS) and Madison Gas and Electric Company (MGE), received oral approval from the Public Service Commission of Wisconsin (PSCW) to install additional emissions reduction technology at the Columbia Energy Center located near Pardeeville, Wisconsin.

This project is designed to reduce mercury (Hg) emissions through an activated carbon injection system and baghouse to comply with Wisconsin’s mercury rule. It’s also designed to reduce sulfur dioxide (SO2) emissions through the installation of dry flue gas desulfurization systems. This equipment will provide flexibility in complying with state and federal SO2 emissions requirements such as the Clean Air Interstate Rule (CAIR), the EPA’s proposed Clean Air Transport Rule (CATR) and the Clean Air Visibility Rule (CAVR).

WPL’s share of the entire project is expected to cost approximately $290 million excluding AFUDC.