The most common process to generate electricity from coal includes pulverization and combustion in a furnace with a boiler. To simplify the things the much as possible the furnace heat converts boiler water to steam, which is then used to spin turbines, and turbines turn generators to create electricity. Efficiency of this process has been improved over the time, and the best way to increase efficiency is to increase the combustion temperature. Coal looks likely to remain the world’s leading fuel to generate electricity for many years, and today about 40% of the world’s electricity comes from coal, and approximately 49% of theUnited Stateselectricity comes from coal.

SOURCE:  http://interestingenergyfacts.blogspot.com/search/label/coal