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Wind energy or wind power is extracted from air flow using wind turbines or sails to produce mechanical or electrical energy. Windmills are used for their mechanical power, windpumps for water pumping, and sails to propel ships. Wind power as an alternative to fossil fuels, is plentiful, renewable, widely distributed, clean, produces no greenhouse gas emissions during operation, and uses little land. The net effects on the environment are far less problematic than those of nonrenewable power sources. Wind farms consist of many individual wind turbines which are connected to the electric power transmission network. Onshore wind is an inexpensive source of electricity, competitive with or in many places cheaper than coal or gas plants.〔David Richard Walwyn, Alan Coli Brent, ''Renewable energy gathers steam in South Africa''. In: ''Renewable and Sustainable Energy Reviews'' 41, (2015), 390–401, .〕〔Robert Gasch, Jochen Twele (ed.): ''Windkraftanlagen. Grundlagen, Entwurf, Planung und Betrieb''. Springer, Wiesbaden 2013, p 569 (German).〕 Offshore wind is steadier and stronger than on land, and offshore farms have less visual impact, but construction and maintenance costs are considerably higher. Small onshore wind farms can feed some energy into the grid or provide electricity to isolated off-grid locations. Wind power is very consistent from year to year but has significant variation over shorter time scales. It is therefore used in conjunction with other electric power sources to give a reliable supply. As the proportion of windpower in a region increases, a need to upgrade the grid, and a lowered ability to supplant conventional production can occur.〔〔 Power management techniques such as having excess capacity, geographically distributed turbines, dispatchable backing sources, sufficient hydroelectric power, exporting and importing power to neighboring areas, using vehicle-to-grid strategies or reducing demand when wind production is low, can in many cases overcome these problems.〔〔Nicola Armaroli, Vincenzo Balzani, ''Towards an electricity-powered world''. In: ''Energy and Environmental Science'' 4, (2011), 3193–3222, p. 3217, .〕 In addition, weather forecasting permits the electricity network to be readied for the predictable variations in production that occur.〔Platt, Reg (21 January 2013) (Wind power delivers too much to ignore ), ''New Scientist''.〕〔Platt, Reg; Fitch-Roy, Oscar and Gardner, Paul (August 2012) (Beyond the Bluster why Wind Power is an Effective Technology ). Institute for Public Policy Research.〕 As of 2014, Denmark has been generating around 40% of its electricity from wind,〔Rasmussen, Jesper Nørskov. "(Vindmøller slog rekord i 2014 )" (In English: New record for wind turbines in 2014 ). ''Energinet.dk'', 6 January 2015. Accessed: 6 January 2015. (Archived ) on 6 January 2015〕〔http://online.wsj.com/articles/denmarks-wind-power-output-rises-to-record-in-first-half-1409750563〕 and at least 83 other countries around the world are using wind power to supply their electricity grids.〔 Wind power capacity has expanded to 369,553 MW by December 2014, and total wind energy production is growing rapidly and has reached around 4% of worldwide electricity usage. == History == (詳細はsails into the wind. For more than two millennia wind-powered machines have ground grain and pumped water. Wind power was widely available and not confined to the banks of fast-flowing streams, or later, requiring sources of fuel. Wind-powered pumps drained the polders of the Netherlands, and in arid regions such as the American mid-west or the Australian outback, wind pumps provided water for live stock and steam engines. The first windmill used for the production of electricity was built in Scotland in July 1887 by Prof James Blyth of Anderson's College, Glasgow (the precursor of Strathclyde University).〔 〕 Blyth's 10 m high, cloth-sailed wind turbine was installed in the garden of his holiday cottage at Marykirk in Kincardineshire and was used to charge accumulators developed by the Frenchman Camille Alphonse Faure, to power the lighting in the cottage,〔 thus making it the first house in the world to have its electricity supplied by wind power.〔 〕 Blyth offered the surplus electricity to the people of Marykirk for lighting the main street, however, they turned down the offer as they thought electricity was "the work of the devil."〔 Although he later built a wind turbine to supply emergency power to the local Lunatic Asylum, Infirmary and Dispensary of Montrose the invention never really caught on as the technology was not considered to be economically viable.〔 Across the Atlantic, in Cleveland, Ohio a larger and heavily engineered machine was designed and constructed in the winter of 1887–1888 by Charles F. Brush,〔Anon. (Mr. Brush's Windmill Dynamo ), ''Scientific American'', Vol. 63 No. 25, 20 December 1890, p. 54.〕 this was built by his engineering company at his home and operated from 1886 until 1900.〔(A Wind Energy Pioneer: Charles F. Brush ), Danish Wind Industry Association. Accessed 2 May 2007.〕 The Brush wind turbine had a rotor 17 m (56 foot) in diameter and was mounted on an 18 m (60 foot) tower. Although large by today's standards, the machine was only rated at 12 kW. The connected dynamo was used either to charge a bank of batteries or to operate up to 100 incandescent light bulbs, three arc lamps, and various motors in Brush's laboratory.〔''History of Wind Energy'' in Cutler J. Cleveland,(ed) ''Encyclopedia of Energy Vol.6'', Elsevier, ISBN 978-1-60119-433-6, 2007, pp. 421–422〕 With the development of electric power, wind power found new applications in lighting buildings remote from centrally-generated power. Throughout the 20th century parallel paths developed small wind stations suitable for farms or residences, and larger utility-scale wind generators that could be connected to electricity grids for remote use of power. Today wind powered generators operate in every size range between tiny stations for battery charging at isolated residences, up to near-gigawatt sized offshore wind farms that provide electricity to national electrical networks. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Wind power」の詳細全文を読む スポンサード リンク
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