Abstract

Coal is a vital component of energy utilization throughout the world, including the United States, where coal is responsible for >50% of the electricity production. Sixteen countries each produce >1% of the world's coal production, with China and the United States leading, each with >23% of world production. In this article, various aspects of coal petrology, chemistry, and physical structure are discussed. Utilization aspects, including coking, combustion, gasification, and liquefaction are considered. Combustion accounts for most of the world utilization, with gasification and other clean-coal technologies holding promise for future applications. In the United States and many other countries, environmental regulations have impacted the quality of coal used in combutstion, with the tendency to use lower sulfur coals evident in the U.S. power industry's shift from Eastern U.S. bituminous to Wyoming subbituminous coals. Coke production, while still an important user of coal, has declined. Liquefaction, despite the promise of providing an alternative to petroleum, has not been widely commercialized.