Black Hills Corporation and Aquila File Acquisition Approval Applications in Colorado, Kansas, Nebraska and Iowa

For Information Contact: Mark T. Thies, Executive Vice President; Dale T. Jahr, Director, Investor Relations

RAPID CITY, SD—April 5, 2007—Black Hills Corporation (NYSE: BKH) and Aquila, Inc. (NYSE: ILA) yesterday filed applications with the Public Utilities Commission of the State of Colorado, the Kansas Corporation Commission, The Nebraska Public Service Commission and the Iowa Utilities Board seeking approval of the proposed acquisition by Black Hills Corporation of Aquila’s electric and natural gas utility operations in Colorado, Kansas, Nebraska and Iowa.

ABOUT BLACK HILLS CORPORATION AND AQUILA
            Black Hills Corporation is a diversified energy company. Our retail businesses are Black Hills Power, an electric utility serving western South Dakota, northeastern Wyoming and southeastern Montana; and Cheyenne Light, Fuel & Power, an electric and gas distribution utility serving the Cheyenne, Wyoming vicinity. Black Hills Energy, the wholesale energy business unit, generates electricity, produces natural gas, oil and coal, and markets energy. More information is available at our Internet website: www.blackhillscorp.com.

Based in Kansas City, Mo., Aquila owns electric power generation and operates electric and natural gas transmission and distribution networks serving nearly 1 million customers in Colorado, Iowa, Kansas, Missouri and Nebraska. More information on Aquila is available at www.aquila.com.