FirstEnergy (NYSE: FE) cannot close its Ashtabula, Eastlake, Bay Shore and Lakeshore coal-fired power plants in Ohio until 2015, according to the Cleveland Plain Dealer.

The PJM Interconnection determined that the plant closings would cause major voltage inadequacies and equipment overheating in the regional grid, the article said.

FirstEnergy will also have to pay up to $1 billion in upgrades to the transmission system in the next three years.

FirstEnergy announced in January 2012 that it would close 2,600 MW of coal-fired generation, including coal-fired power plants in Maryland and West Virginia, which the company still intends to close this year.

According to PJM’s plan, Ashtabula, Lakeshore and three of the five boilers at Eastlake will remain open through early 2015 but operate only when needed, usually during peak electricity demand. When upgrades to the transmission system are completed, the plants will be shut down, the article said. Eastlake’s two larger boilers will be shut down in September as originally planned, but their generators will be equipped with large electric motors and converted to become voltage regulators to help stabilize the transmission lines in the region. The smaller Eastlake and Lakeside turbines will undergo the same retrofit in 2015.

FirstEnergy will also install four combustion turbines that will be used to generate power during peak demand at Eastlake. The company cannot pass on the cost of the turbines to ratepayers because of deregulation, the article said.

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