Overview

Coal is a fossil fuel formed in swamp ecosystems where plant remains were saved by water and mud from oxidization and biodegradation. Coal is a combustible organic sedimentary rock (composed primarily of carbon, hydrogen, and oxygen) formed from ancient vegetation and consolidated between other rock strata to form coal seams. The harder forms, such as anthracite coal, can be regarded as organic metamorphic rocks because of a higher degree of maturation.

Coal is composed primarily of carbon along with assorted other elements, including sulfur. It is the largest single source of fuel for the generation of electricity worldwide, as well as the largest source of carbon dioxide emissions, which have been implicated as the primary cause of global warming. Coal is extracted from the ground by coal mining, either underground mining or open-pit mining (surface mining).

Coal is the one fossil energy source that can play a substantial role as a transitional energy source as one moves from the petroleum- and natural-gas-based economic system to the future economic system based on nondepletable or renewable energy systems. Coal has been used as an energy source for thousands of years. It has many important uses, but most significantly in electricity generation, steel and cement manufacture, and industrial process heating. In the developing world, the use of coal in the household, for heating and cooking, is important. For coal to remain competitive with other sources of energy in the industrialized countries of the world, continuing technologic improvements in all aspects of coal...