View source for Wind farm

[[Category:Done 2018-12-10]] [[Category: Rudi grade Ashley edit]] 
[[Category:Translated to French]]
[[fr:Parc éolien]]
<onlyinclude>A '''wind farm''' is a collection of [[wind turbine]]s within a region used to [[generate electricity]]. Wind farms may be very large, covering areas of hundreds of square [[mile]]s. They can also be [[offshore wind turbine|offshore]], located in a body of water.</onlyinclude><ref name=Win>Wind Energy Technologies Office (Nov.29, 2018). ''How Wind Turbines Work'' [Online] Available: https://www.energy.gov/eere/wind/how-do-wind-turbines-work</ref>

Asia leads [[electrical generation|electricity generation]] by means of [[wind]], with China alone having an installed [[capacity]] of 188 400 [[megawatts electric|MW]] as of 2017. <ref name=ren21>Ren21. (Nov.29, 2018). ''Renewables 2018 Global Status Report'' [Online], Available: http://www.ren21.net/wp-content/uploads/2018/06/17-8652_GSR2018_FullReport_web_-1.pdf</ref> China makes up over 80% of the installed capacity of Asia and contains some of the world's largest wind farms, the largest being the Gansu Wind Farm, with a small portion of it seen in Figure 1. The United States is the second leading country in wind power capacity, with a capacity of approximately 90000 MW, which only about half of China's.<ref name=ren21/>

The [[capacity factor]] of wind farms is relatively low; for many it is around 20% over a full year. This means that only 20% of the installed capacity is used on average, due to the [[intermittent electricity|intermittency]] of wind. This can be compared to the capacity factor of a [[coal-fired power plant]] or a [[nuclear power plant]], both of which typically achieve 90% of their capacity year-round.<ref name=hinrichs>R. A. Hinrichs and M. Kleinbach, "Wind Energy," in ''Energy: Its Use and the Environment'', 5th ed. Toronto, Ont. Canada: Brooks/Cole, 2013, ch.12, sec.E, pp.388-400</ref>

[[File:Gansu.Guazhou.windturbine_farm.sunset.jpg|800px|thumb|center|Figure 1. A small portion of the Gansu Wind Farm in northwestern China, which has a total capacity of over 6000 MW.<Ref>Wikimedia Commons [Online], Available: https://en.wikipedia.org/wiki/File:Gansu.Guazhou.windturbine_farm.sunset.jpg</ref>]]

==Location==

Wind farms require a fairly consistent [[wind]] flow, travelling at just the [[wind power#Wind Speed|right speed]] (not too slow, yet not too fast). Therefore it is important to analyze the [[prevailing winds]] in a given region, in order to determine the ideal spots to place a wind farm.<ref name=potts>G. Potts, ''Where the Wind Blows – Determining Turbine Locations,'' [Online], Available: http://grandbend.northlandpower.ca/site/northland_power___grand_bend_wind_farm/assets/pdf/npi_gbwf_10x12.5_pr02_aug30.pdf</ref> Other factors taken into consideration include relative proximity to structures like buildings and houses, along with possible [[environmental impact]]s of building the farm.<ref name=potts/> There are many guidelines in place to accommodate the building of a wind farm.  

Once a location is selected, the placing of wind turbines is important in order to maximize the amount of [[power]] received from the wind. Turbines must be spaced about 3 to 10 rotor diameters apart (about 180-600 metres for a wind farm using 60 [[meter]] diameter turbines).<Ref name=pp>Portal Planning. (August 24, 2015). ''Spacing of Turbines'' [Online], Available: http://www.planningni.gov.uk/index/policy/policy_publications/planning_statements/pps18/pps18_annex1/pps18_annex1_wind/pps18_annex1_technology/pps18_annex1_spacing.htm</ref> This spacing is made as compromise - compactness of a wind farm would reduce the land costs, however put them too close and the front turbines will block the wind to the turbines behind them, causing them to spin to slowly. This is referred to as "shadowing".<ref name=pp/>

==Power Output and Costs==

The power a turbine is capable of producing has increased drastically since the 1990s, from 100 kW to over 20 000 kW.<ref name=hinrichs/> The cost of turbines has also decreased by about a factor of 3, meaning the building of turbines is much more practical today - it currently costs around $1000 per kW of rated capacity.<ref name=hinrichs/> Because of these reasons, there has been a vast boom in wind farm construction globally in the past decade: from 40 000 MW in 2004 to 370 000 MW in 2014, nearly a tenfold increase.<ref name=gwec>Global Wind Energy Council. (August 24, 2015). ''Global Installed Wind Power Capacity (MW)'' [Online], Available: http://www.gwec.net/wp-content/uploads/2012/06/GLOBAL_INSTALLED_WIND_POWER_CAPACITY_MW_%E2%80%93_Regional_Distribution.jpg</ref>

A wind farm is connected to the [[electrical grid]] just like any other [[power plant]], where a [[transformer]] is used to step-up [[voltage]]s of the electricity in order to reduce [[energy loss]]es. These transformers are often housed within a turbine tower, and the electricity from each turbine is connected to a single point via [[electrical transmission#Power Lines|underground power lines]].<ref>Portal Planning. (August 24, 2015). ''Connection to the Electricity Grid'' [Online], Available: http://www.planningni.gov.uk/index/policy/planning_statements_and_supplementary_planning_guidance/pps18/pps18_annex1/pps18_annex1_wind/pps18_annex1_technology/pps18_annex1_connection.htm</ref>

==For Further Reading== 
*[[Wind]] 
*[[Electricity]] 
*[[Wind turbine]] 
*[[Generator]] 
*[[Mechanical energy]] 
*Or explore a [[Special:Random|random page]]

==References==
{{reflist}}[[Category:Uploaded]]