Coal is primarily used as a solid fuel to produce electricity and heat through combustion. World coal consumption is about 6.2 billion tons annually, of which about 75% is used for the production of electricity. China produced 2.38 billion tonnes in 2006 and India produced about 447.3 million tonnes in 2006. 83.2% of China's electricity comes from coal. The USA consumes about 1.053 billion tonnes of coal each year, using 90% of it for generation of electricity. The world in total produced 6.19 billion tonnes of coal in 2006.

When coal is used for electricity generation, it is usually pulverized and then burned in a furnace with a boiler. The furnace heat converts boiler water to steam, which is then used to spin turbines which turn generators and create electricity. The thermodynamic efficiency of this process has been improved over time. "Standard" steam turbines have topped out with some of the most advanced reaching about 35% thermodynamic efficiency for the entire process, which means 65% of the coal energy is rejected as waste heat into the surrounding environment. Old coal power plants, especially "grandfathered" plants, are significantly less efficient and reject higher levels of waste heat.