Coal, a fossil fuel, is the largest source of energy for the generation of electricity worldwide, Coal is extracted from the ground by mining, either underground or in open pits. Coal is primarily used as a solid fuel to produce electricity and heat through combustion. Coal is the workhorse of the nations electric power industry. The USA consumes about 14% of the world total, using 90% of it for generation of electricity, Coal-fired electric generating plants are the cornerstone of the nations central power system.