Portal:Energy

Most hydroelectric power comes from the potential energy of dammed water driving a water turbine and generator. The energy extracted from water depends on the volume and on the difference in height between the source and the water's outflow. Pumped storage hydroelectricity schemes produce electricity to supply high peak demands by moving water between reservoirs at different elevations. They currently provide the only commercially important means of grid energy storage. At times of low electrical demand, excess generation capacity is used to pump water back into the higher reservoir, from where it can be released through the turbines at short notice. Less common types of hydroelectricity include run-of-the-river, waterwheels, and tidal power schemes.

A major advantage of hydroelectricity is the elimination of fuel costs and the associated carbon emissions although, in tropical regions, decaying plant material behind the dam can sometimes result in greater greenhouse gas emissions than a conventional power station. Other issues include the need to relocate people from areas to be flooded and disruption caused to aquatic ecosystems.

• The Obninsk Nuclear Power Plant was the world's first civilian nuclear power plant while Sellafield (pictured) was the world's first commercial nuclear power station?

• The Chinese energy company Fushun Mining Group operates the largest oil shale plant in the world consisting 220 Fushun-type retorts?

• Three of the four largest power stations in the world are in South America?

• Adriatic LNG is the world's first offshore gravity-based structure LNG regasification terminal?

• The Horse Hollow Wind Energy Center is the world's largest wind farm at 735.5 megawatt?

• Scotland has 85% of the United Kingdom's hydro-electric energy resource?

• The day when Exxon canceled its Colony Shale Oil Project in Colorado is known by locals as "Black Sunday"?

• The Australian energy company Linc Energy is the first company in the world to produce synthetic fuel by combining underground coal gasification and gas-to-liquid technologies?

Born in Ireland, Thomson studied at the University of Glasgow, Scotland. On graduating, he became a mathematics teacher at the Royal Belfast Academical Institution. During his life Thomson published more than 600 scientific papers and filed over 70 patents.

As early as 1845 Thomson pointed out that the experimental results of William Snow Harris were in accordance with the laws of Coulomb. Over the period 1855 to 1867, Thomson collaborated with Peter Guthrie Tait the Treatise on Natural Philosophy that unified the various branches of physical science under the common principle of energy. His inventions included the current balance for the precise specification of the ampere, the standard unit of electric current.

In 1893, Thomson headed an international commission to decide on the design of the Niagara Falls power station. Despite his previous belief in the superiority of direct current electric power transmission, he agreed to use alternating current after seeing a Westinghouse demonstration at the Chicago World's Fair.