Clean coal is the name attributed to coal chemically washed of minerals and impurities, sometimes gasified, burned and the resulting flue gases treated with steam, with the purpose of removing sulfur dioxide, and reburned so as to make the carbon dioxide in the flue gas economically recoverable. The coal industry uses the term "clean coal" to describe technologies designed to enhance both the efficiency and the environmental acceptability of coal extraction, preparation and use , with no specific quantitative limits on any emissions, particularly carbon dioxide.

The burning of coal, a fossil fuel, has been shown to be one of the principal causes of anthropogenic climate change and global warming, according to the United Nations Intergovernmental Panel on Climate Change.Fourth_Assessment_Report" target="_blank">http://en.wikipedia.org/wiki/IPCC_Fourth_Assessment_Report The concept of clean coal is said to be a solution to climate change and global warming by coal industry groups, while environmental groups believe it is greenwash. _Greenpeace is a major opponent of the concept because emissions and wastes are not avoided, but are transferred from one waste stream to another. The 2007 Australian of the Year, paleontologist and environmental activist Tim Flannery made the assertion that "Coal can't be clean".

There are no coal-fired power plants in commercial production which capture all carbon dioxide emissions, so the process is theoretical and experimental and thus a subject of feasibility or pilot studies. It is has been estimated that it will be 2020 to 2025 before any commercial-scale clean coal power stations (coal-burning power stations with carbon capture and sequestration) are commercially viable and widely adopted. This time frame is of concern to environmentalist because of their belief that there is an urgent need to mitigate greenhouse gas emissions and climate change to protect the world economy, according to the Stern report. Even when CO 2 emissions can be caught, there is considerable debate over the necessary carbon capture and storage that must follow.