by Robert S. Kripowicz

About the author: Robert S. Kripowicz is the acting assistant secretary for fossil energy for the U.S. Department of Energy.

Coal is an indispensable part of our nation’s energy mix. Because of its abundance and low cost, coal now accounts for more than half of the electricity generated in this country.

Coal is our nation’s most abundant domestic energy resource. One quarter of all the world’s known coal supplies are found within the United States. In terms of energy value (Btus), coal constitutes approximately 95 percent of U.S. fossil energy reserves. Our nation’s recoverable coal has the energy equivalent of about one trillion barrels of crude oil—comparable in energy content to all the world’s known oil reserves. At present...