UPDATE 1-MidAmerican, Sierra Club in coal plant settlement

* To stop burning coal at some plants by 2016

* May convert in some cases to natural gas

* Sierra Club threatened suit last July

Jan 22 (Reuters) - Utility company MidAmerican Energy Co said it has reached a settlement with the Sierra Club over power plant emissions, which includes a pledge to stop burning coal at certain plants over the next few years.

MidAmerican, a unit of Warren Buffett's Berkshire Hathaway , said in a statement on Tuesday the deal was in response to a July 2012 notice from the environmental group. The Sierra Club said at the time it intended to sue over purported violations of the Clean Air Act.

Under a consent decree filed with a federal court in Iowa, the utility said it would stop burning coal by mid-April 2016 at Neal Energy Center Boilers 1 and 2 and at the Walter Scott Jr. Energy Center Boilers 1 and 2.

Those units produced just over 536 megawatts of electricity, the utility said, adding that it would consider keeping them open with the use of other fuels.

MidAmerican also said it would also stop burning coal at the 137.4-megawatt Riverside Generating Station and would convert it to natural gas instead.

"MidAmerican Energy has been and remains in compliance with the law," the company said, adding that Iowa authorities had not pursued any enforcement actions against any of its plants.

"MidAmerican Energy entered into settlement discussions as a means to avoid costs to its customers, unnecessary delays, and ongoing uncertainty associated with litigation," it said.

The utility serves more than 700,000 customers in Iowa, Illinois, Nebraska and South Dakota.