Sub-bituminous coal

[1] Sub-bituminous coal is primarily used as a fuel for steam-electric power generation.

They contain 15-30% inherent moisture by weight and are non-coking (undergo little swelling upon heating).

Their relatively low density and high water content renders some types of sub-bituminous coals susceptible to spontaneous combustion if not packed densely during storage in order to exclude free air flow.

A major source of sub-bituminous coal in the United States is the Powder River Basin in Wyoming.

Sub-bituminous coals, in the United States, typically have a sulfur content less than 1% by weight, which makes them an attractive choice for power plants to reduce SO2 emissions under the Acid Rain Program.