Coal-fired power: 'Clean coal' technology

When burnt, coal is the dirtiest of all fossil fuels but a range of methods – called clean coal technology (CCT) – is being developed to reduce environmental impact of coal-fired power stations.

The most important of these is carbon capture and storage (CCS), a process designed to trap carbon dioxide, preventing greenhouse gases entering the atmosphere, and storing it deep underground. A range of methods have proved technically feasible but have yet to be shown to be economically viable on a large scale.

Three key methods are post-combustion capture where the carbon dioxide is removed from the flue gas after the fuel has been burned; pre-combustion capture where the fuel isc onverted into carbon dioxide and hydrogenand the former can then be removed before combustionthrough a process called gasification; and oxyfuel combustion which involves burning the fuel in pure oxygen.This last process produces a pure stream of carbon dioxideafter water vapour condenses. The carbon dioxide can then be stored underground, in the ocean or by combining it with metal oxides to make stable minerals such as limestone, which could then be stored or re-used in construction. However, environmentalists have insisted the term clean coal is an oxymoron, focusing on theenvironmental impact of coal extraction, the high cost to sequester carbon and the uncertainty of how to manage end result pollutants.Critics say that such power plants still release large amounts of pollutants compared to renewable energy sources. \[necas\] such as wind or solar power Greenpeace has been a major opponent, insisting such power stations would lock Britain into huge carbon emissions for decades.and signal a surrender of Britain's long-term climate change targets.