Coal-fired electrical power generated in the United States has steadily declined from 46.1% in 2010 to 30% in 2016. The leading source of energy for providing electricity is natural gas at 34% in 2016; second was coal at 30%; third was nuclear power at 20%.

Coal's importance in the generation of electricity, together with its many environmental drawbacks, make it a highly controversial source of energy. There is little doubt that coal is responsible for much pollution and for the release of substantial amounts of climate-damaging greenhouse gases. On the other hand, at the present time coal is vital to the economic security of the USA.

What are the details of coal's impact on our economy, the environment and the world's climate? Can anything be done to make coal itself less harmful? Are there any better substitutes for coal in the generation of electrical power? If so, how feasible is it to implement them and how long will it take? How much coal does the USA and the rest of the world have? How long will our supplies of coal last? The answers to these questions are central to decisions regarding the future use of coal as a source of energy.