Most U.S. coal plants built before 1990

The average age of coal-fired power plants is 39 years old with 88% of them were built between 1950 and 1990, according to U.S. Energy Information Administration. Coal-fired electricity generating capacity accounts for 25% of all electricity generating capacity in the United States.

“About half of the coal capacity operating in 2016 use bituminous coal as their main energy source, a type of coal that comes from Appalachian states such as West Virginia, Kentucky and Pennsylvania,” according to the EIA. “Bituminous coal is the most abundant type of coal in the United States and is more commonly produced in eastern and midwestern states.” Bituminous coal typically has a greater sulfur content than subbituminous coal, which is largely produced in Wyoming.

Coal plants, such as those operating in Arkansas, use subbituminous coal. The fuel source is used by the majority of the plants not using bituminous coal. Less than 5% of coal plants use lignite or other coal types.

Coal electricity generation has fallen as electricity produced with renewable sources and natural gas has risen. Between 2007 and 2016, coal-fired electricity generation has fallen to 1.2 billion kilowatt-hours, from an annual high of 2 billion kilowatt-hours.

Texas has the most coal-fired electricity generating capacity, with 23.6 gigawatts, or 9% of the national total. Nearly all the plants in the state use subbituminous coal. Combined, Indiana and Ohio have at least 15 gigawatts of operating capacity. Maine and Vermont don’t have coal capacity.