American Electric Power (AEP), one of the largest electric utility companies in the United States, plans to burn slightly more steam coal in 2018 than last year at its remaining coal-burning power plants. The Columbus, Ohio-based company should consume approximately 33 million tons of coal from several domestic coal basins, according to a company spokeswoman. That is about a 6% increase over the 2017 coal burn, but it pales in comparison to a decade ago, when AEP regularly burned about 70 million tons of coal in its far-flung plants.

The 33 million-ton figure relates only to AEP’s regulated power plants. The company does not disclose the coal burn for its unregulated or merchant facilities, some of which have been retired by AEP.

They include the 2,400-megawatt J.M. Stuart plant along the Ohio River near Aberdeen, Ohio, and the 600-megawatt Killen plant near Wrightsville, Ohio. AEP and Houston-based merchant generator Dynegy Inc. had been co-owners with Dayton Power & Light Co., which operated the plants until they closed on June 1.

Ohio-based Murray Energy Corp., the largest privately-owned coal company in the US, lobbied to keep the plants open to no avail. At one point, Murray founder and CEO Robert E. Murray implored DP&L to place Stuart and Killen up for sale, suggesting coal industry entities might be interested in buying them.

By mid-2016, AEP had retired approximately 6,500 megawatts of coal-burning generating capacity as part of its plan to comply with the federal Environmental Protection Agency’s Mercury and Air Toxics Standards rules for existing power plants.

Among the coal plants previously retired were Muskingham River in Ohio, Big Sandy in Kentucky, Kammer and Kanawha River in West Virginia, and Clinch River and Glen Lyn in Virginia.

In the past couple of years, the pace of AEP’s coal plant retirements has slowed. Coal still accounts for about 47% of AEP’s total generating capacity of about 33,000 megawatts. AEP serves about 5.4 million customers in 11 states.