BLACK HILLS BEGINS CONSTRUCTION ON NEW CHEYENNE PRAIRIE STATION

May 22, 2013 – Construction has begun on the new Cheyenne Prairie Generating Station power plant near Cheyenne, Wyo., for customers of Black Hills Corp. (NYSE: BKH) subsidiaries Cheyenne Light, Fuel & Power and Black Hills Power.

The power plant site is five miles southeast of downtown Cheyenne and will contain three natural-gas-fired turbines with a total capacity of 132 megawatts.

The plant will include one simple-cycle combustion turbine unit that will be wholly owned by Cheyenne Light. It will also include one combined-cycle unit that will be jointly owned by Cheyenne Light and Black Hills Power.

The plant is scheduled to be placed in service in the fourth quarter of 2014.

David R. Emery, Black Hills Corp.’s chairman, president and chief executive officer, said that a workforce of approximately 340 contractors will be onsite during peak construction and that the plant, once completed, will require 10 to 12 full-time employees to operate the facility on an ongoing basis.

“This plant is an example of how our company continues to safely and reliably support increasing demand for electricity and provide solutions to our customers’ evolving energy needs,” Emery said.

Black Hills Power needs replacement generation for 82 megawatts of older, coal- fired generation that cannot be economically retrofitted to meet new EPA air emissions regulations and must be retired before March 2014. Cheyenne Light is preparing for growing electricity demand due to an increase in economic development and the need to replace a 40 megawatt power supply agreement that ends in 2014.