Coal is a carbon-rich rock formed from plants that grew millions of years ago. Coal is a major source of electricity in the United States and the largest source of energy for electricity generation worldwide.
Coal is a rich source of energy formed from plants that grew in swamps tens to hundreds of millions of years ago. The plants were buried deeply under younger and younger layers of dirt and rock, heated, and compressed into a carbon-rich rock. Burning coal releases more carbon dioxide per unit of energy produced than any other fossil fuel. Read more