FirstEnergy keeping 3 old Ohio coal plants running (Reuters) - A U.S. power grid operator has asked FirstEnergy Corp to keep running three coal-fired plants in Ohio that generate about 885 megawatts in an effort to maintain a reliable supply of electricity, the company said. PJM, the grid operator for 13 U.S. Mid-Atlantic and Midwest states, asked for reliability-must-run arrangements for the 132-MW Units 1-3 at the Eastlake plant, the 244-MW Ashtabula 5 and 245-MW Lake Shore 18, FirstEnergy told investors after its earnings report this week. The plants had been earmarked for retirement this year. FirstEnergy spokesman Mark Durbin said on Thursday that the plants would be available until April 2015 when the U.S. Environmental Protection Agency's (EPA) Mercury and Air Toxics rules are due to be implemented. He could not discuss terms of the must-run contracts. In January, FirstEnergy told PJM that it wanted to shut this year about 2,700 MW of smaller, older coal units in Ohio, Pennsylvania and Maryland, most of which had entered service in the 1950s and 1960s. FirstEnergy said it wanted to retire the old plants because it did not make economic sense to upgrade the units' emissions equipment to meet more-stringent federal environmental rules proposed over the past couple of years. FirstEnergy is not alone in shutting small, older coal plants. Energy companies across the United States have announced planned shutdowns of more than 30,000 MW of coal-fired power plants due to the stricter environmental rules, low natural gas and power prices and weak economic and power demand growth, among other factors. Separately, FirstEnergy said it had filed with PJM in March to interconnect a proposed 800-MW natural gas and oil-fired, combustion turbine peaking plant at the Eastlake facility to help ensure reliable electric service in the area in the future. FirstEnergy did not say how much the turbines would cost, but it said if PJM allows the interconnection and FirstEnergy decides to go ahead with the project, the turbines could enter service in 2015 when the EPA's mercury rules take effect and the coal units with the reliability-must-run contracts shut. FirstEnergy owns nearly 23,000 MW of generating capacity and supplies power to 6 million customers in Ohio, Pennsylvania, New Jersey, West Virginia, Maryland and Virginia. Editing by Dale Hudson