The popularity of coal as an energy source in the U.S. is largely due to its relatively low cost. In 2018, one metric ton of thermal coal cost about 107 U.S. dollars. The cost of coal depends on the carbon content which can change the energy density that coal contains. Coal consumption is rapidly decreasing in the United States due to increased availability of renewables and natural gas, as well as stronger environmental regulations. The U.S. Environmental Protection Agency has regulated coal plants due to mercury pollution, smog, and climate change.
Coal plants in the United States have been the focus of recent energy policy under the Trump administration. A large majority of coal plants in the U.S. where regulators set rates have operating expenses that exceed revenue. In these regions, utilities and regulators often force plants to stay open in order to maintain grid stability. Despite this, many utilities are planning to retire coal plants while replacing them with natural gas and renewables.