Jeffrey Energy Center (Jeffrey EC) is a sub-bituminous coal-fired power plant located in Emmett Township, Pottawatomie County, seven miles (11 km) northwest of St. Marys, Kansas, at (39°17′10″N96°07′01″W). Jeffrey EC is jointly owned by Westar Energy, Topeka, Kansas and Aquila Corp., Kansas City, Missouri. Jeffrey EC is composed of three separate 720-MW units providing a name-plate energy center capacity of 2.16 gigawatts.