Editing Electricity generation (section)

== Methods of generation ==
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Several fundamental methods exist to convert other forms of energy into electrical energy. Utility-scale generation is achieved by rotating [[electric generator]]s or by [[photovoltaic]] systems. A small proportion of electric power distributed by utilities is provided by batteries. Other forms of electricity generation used in niche applications include the [[triboelectric effect]], the [[piezoelectric effect]], the [[thermoelectric effect]], and [[betavoltaics]].

=== Generators ===
{{main|Electric generator}}
[[File: Turbine aalborg.jpg|thumb|right|upright|[[Wind turbine]]s usually provide electrical generation in conjunction with other methods of producing power.]]
[[Electric generator]]s transform [[kinetic energy]] into electricity. This is the most used form for generating electricity based on [[Faraday's law of induction|Faraday's law]]. It can be seen experimentally by rotating a magnet within closed loops of conducting material, e.g. copper wire. Almost all commercial electrical generation uses electromagnetic induction, in which [[mechanical energy]] forces a generator to rotate.

=== Electrochemistry ===
[[File:Hoover dam from air.jpg|thumb|Large dams, such as [[Hoover Dam]] in the United States, can provide large amounts of [[hydroelectric power]]. It has an installed capacity of 2.07 [[Gigawatt|GW]].]]

[[Electrochemistry]] is the direct transformation of [[chemical energy]] into electricity, as in a [[battery (electricity)|battery]]. Electrochemical electricity generation is important in portable and mobile applications. Currently, most electrochemical power comes from batteries.<ref>[http://www.eere.energy.gov/news/archive.cfm/pubDate=%7Bd%20'2003-09-24'%7D#6490 World's Largest Utility Battery System Installed in Alaska] {{Webarchive|url=https://web.archive.org/web/20080627023319/http://www.eere.energy.gov/news/archive.cfm/pubDate%3D%7Bd%20%272003-09-24%27%7D#6490 |date=2008-06-27 }} (press release, 2003-09-24), U.S. Department of Energy. ''"13,670 nickel-cadmium battery cells to generate up to 40 megawatts of power for about 7 minutes, or 27 megawatts of power for 15 minutes."''</ref> [[Primary cell]]s, such as the common [[Zinc–carbon battery|zinc–carbon batteries]], act as power sources directly, but [[secondary cell]]s (i.e. rechargeable batteries) are used for [[electricity storage|storage]] systems rather than primary generation systems. Open electrochemical systems, known as [[fuel cell]]s, can be used to extract power either from natural fuels or from synthesized fuels. [[Osmotic power]] is a possibility at places where salt and fresh water merge.

=== Photovoltaic effect ===
The [[photovoltaic effect]] is the transformation of light into electrical energy, as in [[solar cell]]s. [[Photovoltaic panel]]s convert sunlight directly to DC electricity. [[Power inverter]]s can then convert that to AC electricity if needed. Although sunlight is free and abundant, [[solar power]] electricity is still usually more expensive to produce than large-scale mechanically generated power due to the cost of the panels.{{Cn|date=June 2022}} Low-efficiency silicon solar cells have been decreasing in cost and multijunction cells with close to 30% conversion efficiency are now commercially available. Over 40% efficiency has been demonstrated in experimental systems.<ref>[http://www.doe.gov/news/4503.htm ''New World Record Achieved in Solar Cell Technology''] {{Webarchive |url=https://web.archive.org/web/20070423030653/http://www.doe.gov/news/4503.htm |date=2007-04-23 }} (press release, 2006-12-05), U.S. Department of Energy.</ref> 

Until recently, photovoltaics were most commonly used in remote sites where there is no access to a commercial power grid, or as a supplemental electricity source for individual homes and businesses. Recent advances in manufacturing efficiency and photovoltaic technology, combined with subsidies driven by environmental concerns, have dramatically accelerated the deployment of solar panels. Installed capacity is growing by around 20% per year<ref name="solar" /> led by increases in Germany, Japan, United States, China, and India.