Coal

Coal was a dominant heating fuel up until the 1950s, even in the home heating market. Its use has declined steadily in all but the largest of industrial heating and power generation systems. While it is still one of the least costly and most plentiful energy sources, the cost of handling, coal burning equipment, ash disposal, and general maintenance issues have added to its fall from popularity. In addition, the recent EPA restrictions in the Clean Air Act will further detract from its acceptability in all but the largest applications.