The Duluth-based electric utility plans to convert both coal-fired generators at its Laskin Energy Center in Hoyt Lakes to burn natural gas in 2015.

 Minnesota Power says it will stop burning coal at three of its older generators.

The Duluth-based electric utility plans to convert both coal-fired generators at its Laskin Energy Center in Hoyt Lakes to burn natural gas in 2015. The project will cost $15 million.

The company says one of the three coal-fired units at its Taconite Harbor power plant in Schroeder will be retired. Two other coal units at the plant will keep operating with upgraded environmental controls.

In a statement, Minnesota Power also said it intends to add other natural gas-fired generation after 2020, but gave no details.

The Star Tribune (http://bit.ly/XSOjaf) reports the company says its goal is to supply electricity to its 144,000 customers with one-third renewable energy, one-third natural gas and one-third coal-fired generation.