What is "clean coal"

n. Any technology that may mitigate emissions of carbon dioxide and other greenhouse gasses that arise from the burning of coal for electrical power.

Clean coal is a concept for processes or approaches that mitigate emissions of carbon dioxide (CO) and other greenhouse gases, and naturally occurring radioactive materials, that arise from the use of coal, mainly for electrical power generation, using clean coal technology. Theoretically, there is a contradiction in terms between clean and coal. Currently, the term clean coal is used in the coal industry primarily in reference to carbon capture and storage, which pumps and stores CO emissions underground, and plants using integrated gasification combined cycle (IGCC). IGCC involves coal gasification, which provides a basis for increased efficiency and lower cost in capturing CO emissions. Prior to the current focus on carbon capture and storage, the term clean coal had been used to refer to technologies for reducing emissions of NOx, sulfur, and heavy metals from coal.

There are seven clean coal technologies currently deployed: carbon capture and storage, flue-gas desulfurization, fluidized-bed combustion, integrated gasification combined cycle (IGCC), low nitrogen oxide burners, selective catalytic reduction (SCR), and electrostatic precipitators.