Coal

Coal was a dominant heating fuel up until the 1950's, 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, the coal burning equipment, the ash disposal, and general maintenance issues have added to its decline in popularity. In addition, EPA restrictions imposed in "The Clean Air Act" further detract from its acceptability in all but the largest industrial heating and power generation applications.