Together, Coleman and Wilson account for more than 850 megawatts of generating capacity. If they are sold, the Henderson, Kentucky-based generation and transmission co-op would be left with a single baseload coal plant — the 454-megawatt Robert D. Green station near Robards in northeastern Webster County.

Big Rivers is in the process of installing pollution controls on Green’s two units, built in 1979 and 1981, after the co-op earlier this year received a one-year extension until the spring of 2016 to comply with the federal Environmental Protection Agency’s new Mercury and Air Toxics Standards rule. Earlier this year, the U.S. Supreme Court overturned the rule, sending it back to a lower court for more review.

In recent years, Coleman, temporarily idled since May 2014, and Wilson have consumed more than half of the approximately 4 million tons of steam coal Big Rivers consumes annually. Most of the coal comes from the high-sulfur Illinois Basin.

Big Rivers shuttered Coleman after it lost roughly 60% of its electric load when two large aluminum smelters owned and operated by Century Aluminum Co. in western Kentucky prematurely terminated long-term power purchase agreements and began buying power off the wholesale market in an attempt to reduce power costs.

When Coleman, located near Hawesville along the Ohio River in Hancock County, was closed, Big Rivers said it hoped to place the plant back in service in a few years, possibly in 2017 and 2018.

But the management audit conducted by Concentric Energy Advisors of Marlborough, Massachusetts, for the PSC recommended Coleman should remain idled “and the future of the Wilson plant should be re-examined in the next two to three years.”

“The sale of both plants, even at a loss, should be explored,” it added.

Big Rivers president and CEO Robert Berry said the co-op does not agree with everything in the report. Nevertheless, “we look forward to the opportunity to thoroughly assessment and implement the action plan developed by Concentric,” he said.

A PSC spokesman said the action plan process is expected to commence before the end of this year, but did not know how it would play out over the next two to three years.