The Wyoming Public Service Commission has approved increases in electric and natural-gas rates for Cheyenne Light, Fuel & Power, a subsidiary of Rapid City-based Black Hills Corp.

The increases should bring in an extra $6.7 million a year from electric customers and $4.4 million from natural-gas customers. The rate increases will cover higher costs of providing service, Black Hills Corp. officials said in a news release.

The electric-rate increase is based in part on the addition of the Wygen II power plant to the company's rate base. Wygen II is a 90-megawatt, coal-fired facility now in the final stages of construction and testing.

By including the plant in the rate base, the commissioners have allowed Cheyenne Light, Fuel & Power to add its investment in the new plant to its overall equity in the system. In turn, the company can set its rates to bring in a 10.9 percent return on equity.

Other investments by the company will accommodate the expansion and maintenance of both natural gas and electric distribution systems to serve a growing population and growing demand for energy in the market, officials said.

"We are pleased with the outcome of the rate-making process with the Wyoming Public Service Commission. As part of this action, Wygen II will become a regulated asset of Cheyenne Light," said David R. Emery, chairman, president and chief executive officer of Black Hills Corp. "We believe this power plant will contribute to electric cost stability for our customers in the decades to come."