Megawatt Valley was due to the presence of Ferrybridge C (1966–2016), Eggborough (1967–) and Drax (1974–) coal-fired power stations. This is one of the few remaining concentrations of British coal-fired generation, the power stations are located close to historic coal-mining sites on the South Yorkshire Coalfield and to the River Aire. Drax is a large power station capable of generating 7% of UK electricity demand and, despite being the UK's cleanest and most-efficient coal-fired power station is Europe’s biggest single source of carbon dioxide emissions. The term Megawatt Valley, in relation to the Yorkshire power stations, has been mentioned ("What ever happened
Yorkshire and the Humber stations along the Aire Valley, with Drax being the second largest in Europe with 3,945 MW of capacity, and Eggborough which is owned by the Czech Republic's Energetický a průmyslový holding (EPH) since 2014 and was owned by British Energy until 2010; Ferrybridge C closed on 23 March 2016. The distribution area once looked after by the regional electricity company Yorkshire Electricity is now looked after by Northern Powergrid (former YEDL), owned by Berkshire Hathaway (since 2001) of Omaha, Nebraska. The supply side of the region is now owned by npower (former National Power, now owned by RWE of Essen,