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[[Image:Dreischluchtendamm hauptwall 2006.jpg|thumb|right|280px|The [[Three Gorges Dam]] in China, the [[List of the largest hydroelectric power stations|largest hydro-electric power station]] in the world]]
{{renewable energy sources}}
{{Sustainable energy}}

'''Hydroelectricity''' is electricity generated by [[hydropower]], i.e., the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of [[renewable energy]]. Once a hydroelectric complex is constructed, the project produces no direct waste, and has a considerably lower output level of the [[greenhouse gas]] carbon dioxide ({{co2}}) than [[fossil fuel]] powered energy plants. Worldwide, an installed capacity of 777 [[GWe]] supplied 2998 TWh of hydroelectricity in 2006.<ref>http://www.eia.doe.gov/ Energy Information Administration international statistics database</ref> This was approximately 20% of the world's electricity, and accounted for about 88% of electricity from renewable sources.<ref name="REN21-2006">[http://www.ren21.net/globalstatusreport/download/RE_GSR_2006_Update.pdf Renewables Global Status Report 2006 Update], ''[[REN21]]'', published 2007, accessed 2007-05-16; see Table 4, p. 20.</ref>

==History==
In 1878, the world's first house to be powered with hydroelectricity was Cragside in Northumberland, England. The first [[Thomas Alva Edison|Edison]] hydroelectric power plant - the [[Vulcan Street Plant]] - began operating September 30, 1882, in Appleton, Wisconsin, with an output of about 12.5 kilowatts. The Vulcan Street Plant powered two paper mills and a house.<ref>[http://home.clara.net/darvill/altenerg/hydro.htm Hydroelectric power - energy from falling water] Clara.net</ref>
{{Expand section|date=January 2010}}

==Electricity generation==
[[Image:Water turbine.jpg|thumb|right|230px|[[Water turbine|Hydraulic turbine]] and [[electrical generator]].]]
[[Image:Hydroelectric dam.svg|thumb|right|230px|Hydroelectric dam in cross section]]
{{Main|Electricity generation}}
Most hydroelectric power comes from the [[potential energy]] of [[dam]]med water driving a [[water turbine]] and [[electrical generator|generator]]. In this case the energy extracted from the water depends on the volume and on the difference in height between the source and the water's outflow. This height difference is called the [[head (hydraulic)|head]]. The amount of [[potential energy]] in water is proportional to the head. To deliver water to a turbine while maintaining pressure arising from the head, a large pipe called a [[penstock]] may be used.

[[Pumped storage hydroelectricity]] produces electricity to supply high peak demands by moving water between [[reservoir (water)|reservoirs]] at different elevations. At times of low electrical demand, excess generation capacity is used to pump water into the higher reservoir. When there is higher demand, water is released back into the lower reservoir through a turbine. Pumped storage schemes currently provide the only commercially important means of large-scale [[grid energy storage]] and improve the daily [[capacity factor]] of the generation system. Hydroelectric plants with no reservoir capacity are called [[Run-of-the-river hydroelectricity|run-of-the-river]] plants, since it is not then possible to store water. A [[tidal power]] plant makes use of the daily rise and fall of water due to tides; such sources are highly predictable, and if conditions permit construction of reservoirs, can also be [[Dispatchable generation|dispatchable]] to generate power during high demand periods. Less common types of hydro schemes use water's [[kinetic energy]] or undammed sources such as undershot [[water wheel|waterwheels]].

==Calculating the amount of available power==
{{Main|Hydropower}}
A simple formula for approximating electric power production at a hydroelectric plant is: <math> P = \rho hrgk </math>,
where <math>P</math> is Power in watts, <math>\rho</math> is the density of water (~1000&nbsp;kg/m<sup>3</sup>), <math>h</math> is height in meters, <math>r</math> is flow rate in cubic meters per second, <math>g</math> is acceleration due to [[gravity]] of 9.8 m/s<sup>2</sup>, and <math>k</math> is a coefficient of efficiency ranging from 0 to 1. Efficiency is often higher (that is, closer to 1) with larger and more modern turbines.

Annual electric energy production depends on the available water supply. In some installations the water flow rate can vary by a factor of 10:1 over the course of a year.

== Industrial hydroelectric plants ==
While many hydroelectric projects supply public electricity networks, some are created to serve specific [[industry|industrial]] enterprises. Dedicated hydroelectric projects are often built to provide the substantial amounts of electricity needed for [[aluminium]] electrolytic plants, for example. In the Scottish Highlands of the United Kingdom, there are examples at Kinlochleven and Lochaber, constructed during the early years of the 20th century. The [[Grand Coulee Dam]], long the world's largest, switched to support Alcoa aluminum in Bellingham, Washington, United States for American World War II airplanes before it was allowed to provide irrigation and power to citizens (in addition to aluminum power) after the war. In Suriname, the [[Brokopondo Reservoir]] was constructed to provide electricity for the Alcoa aluminium industry. New Zealand's [[Manapouri Power Station]] was constructed to supply electricity to the [[aluminium]] [[smelter]] at Tiwai Point. As of 2007 the [[Kárahnjúkar Hydropower Project]] in Iceland remains controversial.<ref>[http://www.savingiceland.org/camp2007 Summer of International dissent against Heavy Industry], ''Saving Iceland'', published 2007, accessed 2007-05-17</ref>

==Largest hydro-electric plants ==
{{Main|List of largest hydroelectric power stations}}
[[Image:Three gorges dam from space.jpg|thumb|350px|The Yangtze River at Hubei, China showing the Three Gorges Dam (left), Gezhouba Dam (right).]]
The [[Three Gorges Dam]] complex on the Yangtze River in Hubei, China, has the world's largest generating capacity and generates the most electricity in the world. It includes 2 generating stations. They are the [[Three Gorges Dam]] (22,500 MW when completed) and [[Gezhouba Dam]] (3,115 MW). {{As of|2009}}, the total generating capacity of this complex is 21,515 MW. The whole project is planned to be completed in 2011, when the total generating capacity will be 25,615 MW. In 2008, this complex generated  97.9 TWh of electricity. 

The Itaipu power plant on the Paraná River on the Brazil-Paraguay border currently produces second most hydroelectricity in the world. With 20 generator units and 14,000 MW of installed capacity, in 2008 the Itaipu power plant reached a new historic record for electricity production by generating {{convert|94.68|TWh|TJ|abbr=off|lk=on}}.

== Small-scale hydro-electric plants ==
{{Main|Small hydro}}
Although large hydroelectric installations generate most of the world's hydroelectricity, some situations require small hydro plants. These are defined as plants producing up to 10 megawatts, or projects up to 30 megawatts in North America. A small hydro plant may be connected to a distribution grid or may provide power only to an isolated community or a single home. Small hydro projects generally do not require the protracted economic, engineering and environmental studies associated with large projects, and often can be completed much more quickly. A small hydro development may be installed along with a project for flood control, irrigation or other purposes, providing extra revenue for project costs. In areas that formerly used waterwheels for milling and other purposes, often the site can be redeveloped for electric power production, possibly eliminating the new environmental impact of any demolition operation. Small hydro can be further divided into mini-hydro, units around 1 MW in size, and [[micro hydro]] with units as large as 100&nbsp;kW down to a couple of kW rating.<ref name="REN21-2006">[http://www.ren21.net/globalstatusreport/download/RE_GSR_2006_Update.pdf Renewables Global Status Report 2006 Update], ''[[REN21]]'', published 2006, accessed 2007-05-16</ref>

Small hydro schemes are particularly popular in China, which has over 50% of world small hydro capacity.<ref name="REN21-2006" />

Small hydro units in the range 1 MW to about 30 MW are often available from multiple manufacturers using standardized "water to wire" packages; a single contractor can provide all the major mechanical and electrical equipment (turbine, generator, controls, switchgear), selecting from several standard designs to fit the site conditions. Micro hydro projects use a diverse range of equipment; in the smaller sizes industrial centrifugal pumps can be used as turbines, with comparatively low purchase cost compared to purpose-built turbines.

== Advantages ==
[[Image:Stwlan.dam.jpg|thumb|right|230px|The upper reservoir and dam of the [[Ffestiniog power station|Ffestiniog pumped storage scheme]]. 360 megawatts of electricity can be generated within 60 seconds of the need arising.]]

===Economics===
The major advantage of hydroelectricity is elimination of the cost of fuel. The cost of operating a hydroelectric plant is nearly immune to increases in the cost of [[fossil fuel]]s such as [[Petroleum|oil]], [[natural gas]] or coal, and no imports are needed.

Hydroelectric plants also tend to have longer economic lives than fuel-fired generation, with some plants now in service which were built 50 to 100 years ago.<ref>[http://reme.epfl.ch/webdav/site/reme/users/106542/public/SHS4/Gr01.pdf Hydropower – A Way of Becoming Independent of Fossil Energy?]</ref> Operating labor cost is also usually low, as plants are automated and have few personnel on site during normal operation.

Where a dam serves multiple purposes, a hydroelectric plant may be added with relatively low construction cost, providing a useful revenue stream to offset the costs of dam operation. It has been calculated that the sale of electricity from the [[Three Gorges Dam]] will cover the construction costs after 5 to 8 years of full generation.<ref>[http://www.waterpowermagazine.com/story.asp?storyCode=2041318 Beyond Three Gorges in China]</ref>

===Greenhouse gas emissions===
Since hydroelectric dams do not burn fossil fuels, they do not directly produce [[carbon dioxide]] (a greenhouse gas). While some carbon dioxide is produced during manufacture and construction of the project, this is a tiny fraction of the operating emissions of equivalent fossil-fuel electricity generation. One measurement of greenhouse gas related and other externality comparison between energy sources can be found in the ExternE project by the Paul Scherrer Institut and the University of Stuttgart which was funded by the European Commission.<ref name="ExternEFTR">{{cite web|url=http://www.externe.info/expoltec.pdf|title=Final Technical Report, Version 2|coauthors=Rabl A., Spadaro J., Bickel P., Friedrich R., Droste-Franke B., Preiss P., Int Panis L., Diakoulaki D., Markandya A., Hunt A., Scasny M., Melichar J., Havranek M., Maca V., Foltynova H., Dones R., Heck T., Bauer C., Hirschberg S., Kudelko M.|date=August 2005|work=Externalities of Energy: Extension of Accounting Framework and Policy Applications|publisher=European Commission|accessdate=2009-09-01}}</ref> According to this project, hydroelectricity produces the least amount of [[greenhouse gases]] and [[externality]] of any energy source<ref name="ExternEGraphs">{{cite web|url=http://gabe.web.psi.ch/projects/externe_pol/index.html|title=External costs of electricity systems (graph format)|date=2005|work=ExternE-Pol|publisher=Technology Assessment / GaBE (Paul Scherrer Institut)|accessdate=2009-09-01}}</ref>. Coming in second place was [[wind energy|wind]], third was [[nuclear energy]], and fourth was [[solar energy|solar]] [[photovoltaic]]<ref name="ExternEGraphs"/>. The extremely positive [[greenhouse gas]] impact of hydroelectricity is found especially in temperate climates. The above study was for local energy in Europe; presumably similar conditions prevail in North America and Northern Asia, which all see a regular, natural freeze/thaw cycle (with associated seasonal plant decay and regrowth).

===Related activities===
Reservoirs created by hydroelectric schemes often provide facilities for [[List of water sports|water sports]], and become tourist attractions in themselves. In some countries, [[aquaculture]] in reservoirs is common. [[Multipurpose reservoir|Multi-use dams]] installed for [[irrigation]] support [[agriculture]] with a relatively constant water supply. Large hydro dams can control floods, which would otherwise affect people living downstream of the project.

==Disadvantages==
[[Image:Hydro Warning.JPG|thumb|right|230px|Recreational users must exercise extreme care when near hydroelectric dams, power plant intakes and [[spillway]]s.<ref>[http://www.opg.com/power/hydro/ Stay Clear, Stay Safe], ''Ontario Power Generation''</ref>]]
===Failure Hazard===
[[Dam failure]]s have been some of the largest man-made disasters in history.
Also, good design and construction are not an adequate guarantee of safety.
Dams are tempting industrial targets for wartime attack, [[sabotage]] and terrorism.

For example, the [[Banqiao Dam]] failure in Southern China directly resulted in the deaths of 26,000 people, and another 145,000 from epidemics. Millions were left homeless.
Also, the creation of a dam in a geologically inappropriate location may cause disasters like the one of the [[Vajont Dam]] in Italy, where almost 2000 people died, in 1963.
<ref>See the references for the articles in the list of [[Dam failure]]s. Duplicating them here is wasteful.</ref>

Smaller dams and [[micro hydro]] facilities create less risk, but can form continuing hazards
even after they have been decommissioned.
For example, the small [[Kelly Barnes Dam]] failed in 1967, causing 39 deaths with the Toccoa Flood,
ten years after its power plant was decommissioned in 1957.
<ref>[http://ga.water.usgs.gov/news/historical-toccoa/ Toccoa Flood] USGS Historical Site, retrieved 02sep2009</ref>

===Environmental damage===
Large reservoirs required for the operation of hydroelectric powerplants result in submersion of extensive areas upstream of the dams, destroying biologically rich and productive lowland and riverine valley forests, marshland and grasslands. The loss of land is often exacerbated by the fact that reservoirs cause [[habitat fragmentation]] of surrounding areas.

Hydroelectric projects can be disruptive to surrounding aquatic [[ecosystem]]s both upstream and downstream of the plant site. For instance, studies have shown that dams along the Atlantic and Pacific coasts of North America have reduced [[salmon]] populations by preventing access to [[spawn (biology)|spawning]] grounds upstream, even though most dams in salmon habitat have [[fish ladder]]s installed. Salmon [[spawn (biology)|spawn]] are also harmed on their migration to sea when they must pass through [[water turbine|turbines]]. This has led to some areas transporting smolt downstream by barge during parts of the year. In some cases dams have been demolished (for example the [[Marmot Dam]] demolished in 2007)<ref>{{cite web | url=http://www.portlandgeneral.com/community_and_env/hydropower_and_fish/sandy/default.aspx | title=Sandy River – Marmot Dam’s removal in 2007 has returned the Sandy River to a wild, free-flowing river | publisher=Portland General Electric | accessdate=2009-05-10 }}</ref> because of impact on fish. Turbine and power-plant designs that are easier on aquatic life are an active area of research. Mitigation measures such as fish ladders may be required at new projects or as a condition of re-licensing of existing projects.

Generation of hydroelectric power changes the downstream river environment. Water exiting a turbine usually contains very little suspended sediment, which can lead to scouring of river beds and loss of riverbanks.<ref>[http://internationalrivers.org/en/node/1476 Sedimentation Problems with Dams]</ref>  Since turbine gates are often opened intermittently, rapid or even daily fluctuations in river flow are observed. For example, in the Grand Canyon, the daily cyclic flow variation caused by [[Glen Canyon Dam]] was found to be contributing to erosion of sand bars. Dissolved [[oxygen]] content of the water may change from pre-construction conditions. Depending on the location, water exiting from turbines is typically much warmer than the pre-dam water, which can change aquatic faunal populations, including endangered species, and prevent natural freezing processes from occurring. Some hydroelectric projects also use [[canal]]s to divert a river at a shallower gradient to increase the head of the scheme. In some cases, the entire river may be diverted leaving a dry riverbed. Examples include the Tekapo and Pukaki Rivers in New Zealand.

=== Greenhouse gas emissions ===

[[Image:Bonnington hydroelectic power station.JPG|right|thumb|Bonnington hydroelectric power station, River Clyde, Scotland.]]

Lower positive impacts are found in the tropical regions, as it has been noted that the reservoirs of power plants in tropical regions may produce substantial amounts of [[methane]] and [[carbon dioxide]]. This is due to plant material in flooded areas decaying in an [[Hypoxia (environmental)|anaerobic]] environment, and forming methane, a very potent [[greenhouse gas]]. According to the [[World Commission on Dams]] report<ref>[http://www.dams.org/report/ WCD Findal Report, Retrieved 7/10/2009]</ref>, where the reservoir is large compared to the generating capacity (less than 100 watts per square metre of surface area) and no clearing of the forests in the area was undertaken prior to impoundment of the reservoir, greenhouse gas emissions from the reservoir may be higher than those of a conventional oil-fired thermal generation plant.<ref>[http://www.newscientist.com/article.ns?id=dn7046 Hydroelectric power's dirty secret revealed]</ref> Although these emissions represent carbon already in the biosphere, not fossil deposits that had been sequestered from the carbon cycle, there is a greater amount of [[methane]] due to [[Hypoxia (environmental)|anaerobic]] decay, causing greater damage than would otherwise have occurred had the forest decayed naturally.

[[Image:Bonnington Hydroelectric power station pipes.JPG|left|upright|thumb|The pipes supplying water from the River Clyde to Bonnington hydroelectric power station, Scotland.]]
In boreal reservoirs of Canada and Northern Europe, however, greenhouse gas emissions are typically only 2% to 8% of any kind of conventional fossil-fuel thermal generation. A new class of underwater logging operation that targets drowned forests can mitigate the effect of forest decay.<ref>[http://inhabitat.com/2006/12/01/rediscovered-wood-the-triton-sawfish/#more-1973 Inhabitat » “Rediscovered” Wood & The Triton Sawfish]</ref>

In 2007, International Rivers accused hydropower firms for cheating with fake carbon credits under the [[Clean Development Mechanism]] (CDM), for hydropower projects already finished or under construction at the moment they applied to join the CDM. These carbon credits – of hydropower projects under the CDM in developing countries – can be sold to companies and governments in rich countries, in order to comply with the Kyoto protocol.<ref>{{cite web | url=http://www.guardian.co.uk/environment/2007/dec/03/climatechange.greenpolitics1 | title=Power firms accused of emissions trade cheating | author=Nick Davies | publisher=The Guardian | date=3 December 2007 | accessdate=2009-05-10 }}</ref>

===Population relocation===
Another disadvantage of hydroelectric dams is the need to relocate the people living where the reservoirs are planned. In February 2008, it was estimated that 40-80 million people worldwide had been physically displaced as a direct result of dam construction.<ref>[http://internationalrivers.org/en/way-forward/world-commission-dams/world-commission-dams-framework-brief-introduction Briefing of World Commission on Dams]</ref> In many cases, no amount of compensation can replace ancestral and cultural attachments to places that have spiritual value to the displaced population. Additionally, historically and culturally important sites can be flooded and lost.

Such problems have arisen at the [[Aswan Dam]] in Egypt between 1960 and 1980, the [[Three Gorges Dam#Relocation of local residents|Three Gorges Dam]] project in China, the [[Clyde Dam]] in New Zealand and the [[Ilısu Dam]] in Southeastern Turkey.

===Affected by flow shortage===
Changes in the amount of river flow will correlate with the amount of energy produced by a dam. Siltation, lower river flows because of drought, climate change or upstream dams and diversions will reduce the amount of live storage in a reservoir therefore reducing the amount of water that can be used for hydroelectricity. The result of diminished river flow can be power shortages in areas that depend heavily on hydroelectric power.

==Comparison with other methods of power generation==
{{No footnotes|section|date=August 2008}}
[[Image:Power Station of Aswan dam.jpg|right|thumb|The hydroelectric power station of [[Aswan Dam]], Egypt]]
[[Image:Vianden lake.jpg|thumb|right|Hydroelectric reservoir in Vianden, Luxembourg]]
Hydroelectricity eliminates the [[flue gas emissions from fossil fuel combustion]], including pollutants such as sulfur dioxide, nitric oxide, carbon monoxide, dust, and mercury in the [[coal]]. Hydroelectricity also avoids the hazards of [[coal mining]] and the indirect health effects of coal emissions.
Compared to [[nuclear power]], hydroelectricity generates no [[nuclear waste]], has none of the dangers associated with [[uranium mining]], nor [[Nuclear and radiation accidents|nuclear leaks]]. Unlike uranium, hydroelectricity is also a renewable energy source.

Compared to [[wind farm]]s, hydroelectricity power plants have a more predictable load factor. If the project has a storage reservoir, it can be dispatched to generate power when needed. Hydroelectric plants can be easily regulated to follow variations in power demand.

Unlike fossil-fueled combustion turbines, construction of a hydroelectric plant requires a long lead-time for site studies, hydrological studies, and environmental impact assessment. Hydrological data up to 50 years or more is usually required to determine the best sites and operating regimes for a large hydroelectric plant. Unlike plants operated by fuel, such as fossil or nuclear energy, the number of sites that can be economically developed for hydroelectric production is limited; in many areas the most cost effective sites have already been exploited. New hydro sites tend to be far from population centers and require extensive transmission lines. Hydroelectric generation depends on rainfall in the watershed, and may be significantly reduced in years of low rainfall or snowmelt. Long-term energy yield may be affected by climate change. Utilities that primarily use hydroelectric power may spend additional capital to build extra capacity to ensure sufficient power is available in low water years.

In parts of Canada (the provinces of British Columbia, Manitoba, Ontario, Quebec, Newfoundland and Labrador) hydroelectricity is used so extensively that the word "hydro" is often used to refer to any [[electricity]] delivered by a power utility.<ref>http://archives.cbc.ca/economy_business/energy/topics/1750/</ref> The government-run power utilities in these provinces are called [[BC Hydro]], [[Manitoba Hydro]], [[Hydro One]] (formerly "Ontario Hydro"), [[Hydro-Québec]] and [[Newfoundland and Labrador Hydro]] respectively. Hydro-Québec is the world's largest hydroelectric generating company, with a total installed capacity (2007) of 35,647 MW, including 33,305 MW of hydroelectric generation<ref name="HQ2007">Hydro-Québec. [http://www.hydroquebec.com/publications/en/annual_report/2007/pdf/hydro2007en_complete.pdf 2007 Annual Report]. Montreal, April 2008.</ref>.

== Countries with the most hydro-electric capacity ==
The ranking of hydro-electric capacity is either by actual annual energy production or by installed capacity power rating. A hydro-electric plant rarely operates at its full power rating over a full year; the ratio between annual average power and installed capacity rating is the [[capacity factor]]. The installed capacity is the sum of all generator nameplate power ratings. Sources came from ''BP Statistical Review - Full Report 2009''<ref>[http://www.bp.com/liveassets/bp_internet/globalbp/globalbp_uk_english/reports_and_publications/statistical_energy_review_2009/STAGING/local_assets/downloads/spreadsheets/statistical_review_full_report_workbook_2009.xls#'Hydro Consumption TWh'!A1]</ref>

The top six dams, in descending order of their annual electricity generation, are: the [[Three Gorges Dam]] in China, the [[Itaipu Dam]] on the border of Paraguay and Brazil, the [[Guri Dam]] in Venezuela, the [[Tucurui dam]] in Brazil, the [[Sayano-Shushenskaya hydroelectric station|Sayano-Shushenskaya Dam]] in Russia and the [[Krasnoyarsk hydroelectric dam]], also in Russia (see [[List of the largest hydroelectric power stations]]).

Brazil, Canada, Norway, Switzerland and Venezuela are the only countries in the world where the majority of the internal electric energy production is from hydroelectric power, while Paraguay not only produces 100% its electricity from hydroelectric dams, but exports 90% of its production to Brazil and to Argentina. Norway produces 98–99% of its electricity from hydroelectric sources.<ref name=norway/>

{| class="wikitable sortable"
|- bgcolor=#CCDDEE
|-
! Country
! Annual Hydroelectric<br>Energy Production (TWh)
! Installed<br>Capacity (GW)
! Capacity<br>Factor
! Percent of<br>all electricity
|-
| {{flag|China}} (2009)<ref>[nyj.ndrc.gov.cn/ggtz/W020100106293569392607.doc]</ref>
| 652.05
| 196.79
| 0.37
|22.25
|-
| {{flag|Canada}}
| 369.5
| 88.974
| 0.59
|61.12
|-
| {{flag|Brazil}}
| 363.8
| 69.080
| 0.56
|85.56
|-
| {{flag|United States}}
| 250.6
| 79.511
| 0.42
|5.74
|-
| {{flag|Russia}}
| 167.0
| 45.000
| 0.42
|17.64
|-
| {{flag|Norway}}
| 140.5
| 27.528
| 0.49
| 98.25<ref name=norway>{{cite news |first= |last= |authorlink= |coauthors= |title=Binge and purge  |url=http://www.economist.com/displaystory.cfm?story_id=12970769 |quote=98-99% of Norway’s electricity comes from hydroelectric plants. |work=The Economist |date=2009 |accessdate=2009-01-30 }}</ref>
|-
| {{flag|India}}
| 115.6
| 33.600
| 0.43
|15.80
|-
| {{flag|Venezuela}}
| 86.8
| -
| -
|67.17
|-
| {{flag|Japan}}
| 69.2
| 27.229
| 0.37
|7.21
|-
| {{flag|Sweden}}
| 65.5
| 16.209
| 0.46
|44.34
|-
| {{flag|Paraguay}} (2006)
| 64.0
| -
| -
|
|-
| {{flag|France}}
| 63.4
| 25.335
| 0.25
|11.23
|}
{{Energy country lists|state=collapsed}}

== Old hydro-electric power stations ==
===Australia===
* A small hydroelectric station, generating 650&nbsp;kW, opened at Waratah, Tasmania in 1885.
* [[Duck Reach Power Station|Duck Reach]], Launceston, Tasmania. Completed 1895. The first publicly owned hydro-electric plant in the Southern Hemisphere. Supplied power to the city of Launceston for street lighting.
* The Snowy Mountains Scheme has turbines all along the tunnel so it, in some perspectives it is also another hydroelectric station. However, it only operates during peak hours of the day and mostly during the evening and early night. It supplies electricity to all over the regions of New South Wales.

===Canada===
* Decew Falls 1, St. Catharines, Ontario completed 25 August 1898. Owned by [[Ontario Power Generation]]. Four units are still operational. Recognized as an IEEE Milestone in Electrical Engineering & Computing by the IEEE Executive Committee in 2002.

* The oldest continuously operated hydroelectric generator in Canada is located in St. Stephen, New Brunswick. Part of the construction of the Milltown Cotton Mill, this rope-driven generator originally powered the electric lights for the mill when it opened in 1882, and in 1888 started providing power to homes in the town. [[NB Power]] now owns and operates this as part of the Milltown Dam hydroelectric station.

===Chile===
* Chivilingo was the first hydroelectric plant in Chile and the second in South America. With first power produced in 1897, it has two [[Pelton wheel]] turbines each turning a 215&nbsp;kW generator. It was installed to provide power to mines and the city of Lota, Chile.<ref>Carl Sulzberger, ''The Chivilingo Plant- Early Hydropower in Chile'', in ''IEEE Power & Energy, Volume 6, No. 4 July/August 2008, ISSN 1540-7977, pg. 60</ref>

===United States===
* Appleton, Wisconsin completed 1882, A waterwheel on the Fox river supplied the first commercial hydroelectric power for lighting to two paper mills and a house, two years after [[Thomas Edison]] demonstrated incandescent lighting to the public. Within a matter of weeks of this installation, a power plant was also put into commercial service at Minneapolis.

* [[Robert Moses Niagara Power Plant|Niagara Falls]], New York. Operation began locally in 1895 and power was transmitted to Buffalo, New York, in 1896.

* Claverack Creek, in Stottville, New York, believed to be the oldest hydro power site in the United States. The turbine, a Morgan Smith, was constructed in 1869 and installed 2 years later. It is one of the earliest water wheel installations in the United States to generate electricity. It is owned today by Edison Hydro. {{Citation needed|date=February 2007}}

* The oldest continuously operated commercial hydroelectric plant in the United States is built on the Hudson River at Mechanicville, New York.  The seven 750&nbsp;kW units at this station initially supplied power at a [[utility frequency|frequency]] of 38&nbsp;Hz, but later were increased in speed to 40&nbsp;Hz.  It went into commercial service 22 July 1898.  It is now being restored to its original condition and  remains in commercial operation.<ref>''The Historic Mechanicville Hydroelectric Station  Part 1: The Early Days'', IEEE Industry Applications Magazine, Jan/Feb. 2007</ref>

==Major schemes under construction==
{{No footnotes|section|date=August 2008}}
Only projects with generating capacity greater than or equal to 2,000 MW are listed.
{| class="wikitable sortable"
|-
! Name
! Maximum Capacity
! Country
! Construction started
! Scheduled completion
! Comments
|-
|[[Xiluodu Dam]]
|  12,600 MW
| China
|December 26, 2005
|2015
|Construction once stopped due to lack of environmental impact study.
|
|-
|[[Siang Upper HE Project]]
|11,000 MW
| India
|April, 2009
|2024
|Multi-phase construction over a period of 15 years. Construction was delayed due to dispute with China.{{Citation needed|date=February 2010}}
|
|-
|[[TaSang Dam]]
|7,110 MW
| Burma
|March, 2007
|2022
|Controversial 228 meter tall dam with capacity to produce 35,446 Ghw annually.
|
|-
|[[Xiangjiaba Dam]]
| 6,400 MW
| China
|November 26, 2006
|2015
|
|-
|[[Longtan Dam]]
| 6,300 MW
| China
|July 1, 2001
|December 2009
|
|-
|[[Nuozhadu Dam]]
|   5,850 MW
| China
| 2006
|2017
|
|-
|[[Jinping 2 Hydropower Station]]
|   4,800 MW
| China
|January 30, 2007
|2014
|To build this dam, 23 families and 129 local residents need to be moved. It works with [[Jinping 1 Hydropower Station]] as a group.
|-
|[[Laxiwa Dam]]
|  4,200 MW
| China
|April 18, 2006
|2010
|
|-
|[[Xiaowan Dam]]
| 4,200 MW
| China
|January 1, 2002
|December 2012
|
|-
|[[Jinping 1 Hydropower Station]]
|  3,600 MW
| China
|November 11, 2005
|2014
|
|-
|[[Pubugou Dam]]
|  3,300 MW
| China
|March 30, 2004
|2010
|
|-
|[[Goupitan Dam]]
|  3,000 MW
| China
|November 8, 2003
|2011
|
|-
|[[Guanyinyan Dam]]
|  3,000 MW
| China
|2008
|2015
|Construction of the roads and spillway started.
|-
|[[Lianghekou Dam]]<ref>http://www.ehdc.com.cn/newsite/DisplayNewsMaster/ShowNews.aspx?Id=1175</ref>
|  3,000 MW
| China
|2009
|2015
|
|-
|[[Boguchan Dam]]
|  3,000 MW
| Russia
|1980
|2010
|
|-
|[[Chapetón]]
|  3,000 MW
| Argentina
|
|
|
|-
|[[Dagangshan]]
|  2,600 MW
| China
|August 15, 2008<ref>http://www.cb600.cn/info_view.asp?id=1357280</ref>
|2014
|
|-
|[[Jinanqiao Dam]]
|  2,400 MW
| China
|December 2006
|2010
|
|-
|[[Guandi Dam]]
|  2,400 MW
| China
|November 11, 2007
|2012
|-
|[[Liyuan Dam]]
|  2,400 MW
| China
|2008<ref>http://zt.xxgk.yn.gov.cn/canton_model12/newsview.aspx?id=368628</ref>
|
|
|-
|[[Tocoma Dam]] Bolívar State
|2,160 MW
| Venezuela
|2004
|2014
|This new power plant would be the last development in the Low Caroni Basin, bringing the total to six power plants on the same river, including the 10,000MW [[Guri (Simón Bolívar)|Guri Dam]].<ref>{{cite web|url=http://idbgroup.org/exr/doc98/pro/pvel1003-06eng.pdf|format=PDF|title=Caroní River Watershed Management Plan|last=Staff|year=2004|publisher=Inter-America Development Bank|accessdate=2008-10-25}}</ref>
|-
|[[Ludila Dam]]
|  2,100 MW
| China
|2007
|2015
|Construction halt due to lack of the evnironmental assessment.
|-
|[[Shuangjiangkou Dam]]
|  2,000 MW
| China
|December, 2007<ref>http://www.cjwsjy.com.cn/News/Company/200808055706.htm</ref>
|
|The dam will be 314 m high.
|-
|[[Ahai Dam]]
|  2,000 MW
| China
|July 27, 2006
|
|
|-
|[[Subansiri Lower Dam]]
| 2,000 MW
| India
|2005
|2012
|
|}

==Proposed major hydroelectric projects==
{{No footnotes|section|date=August 2008}}
Only projects with generating capacity greater than or equal to 2,000 MW are listed.

{| class="wikitable sortable"
|-
! Name
! Maximum Capacity
! Country
! Construction starts
! Scheduled completion
! Comments
|-
|[[Red Sea dam]]
|  50,000 MW
| Africa/Middle East
|Unknown
|Unknown
|Still in planning, would be largest dam in the world
|-
|[[Inga Dam|Grand Inga]]
|  40,000 MW
| Democratic Republic of the Congo
|2010
|Unknown
|
|-
|[[Baihetan Dam]]
|  13,050 MW
| China
|2009
|2015
|Still in planning
|
|-
|[[Belo Monte Dam]]
|  11,233 MW
| Brazil
|Unknown
|2014
|Provisional environmental license approved
|
|-
|[[Wudongde Dam]]
|  7,500 MW
| China
|2009
|2015
|Still in planning
|-
|[[Rampart Dam]]
|  4,500 MW
| United States
|
|
|Canceled
|-
|[[Maji Dam]]
|  4,200 MW
| China
|2008
|2013
|
|-
|[[Songta Dam]]
|  4,200 MW
| China
|2008
|2013
|
|-
|[[Liangjiaren Dam]]
|  4,000 MW
| China
|2009
|2015
|Still in planning
|-
|[[Jirau Dam]]
|  3,300 MW
| Brazil
|2007
|2012
|
|-
|[[Pati Dam]]
|  3,300 MW
| Argentina
|
|-
|[[Santo Antônio Dam]]
|  3,150 MW
| Brazil
|2007
|2012
|
|-
|[[Dibang Dam]]
|  3,000 MW
| India
|
|-
|[[Lower Churchill Hydroelectric Generation Project|Lower Churchill]]
|  2,800 MW
| Canada
|2009
|2014
|
|-
|[[HidroAysén]]
|  2,750 MW
| Chile
|
| 2020
|
|-
|[[Lenggu Dam]]
|  2,718 MW
| China
|2015
|
|-
|[[Changheba Dam]]
|  2,200 MW
| China
|2009
|2015
|
|-
|[[Subansiri Upper HE Project]]
|  2,500 MW
| India
|2012
|Unknown
|
|-
|[[Banduo 1 Dam]]
|  2,000 MW
| China
|2009
|
|
|-
|}

==Cost==
===United States===
In the United States, a study is required before constructing a hydroelectric project. In 2008, a study could cost up to $50,000 for a {{convert|100|ft}} run of a stream. Both federal and state licenses were required. A license typically cost between $150,000 and $1 million. A project earns money from the sale of energy, the sale of capacity, and the sale of renewable energy credits.<ref>{{cite book | author = Gresser, Joseph| title = Panel considers small hydro power potential | publisher = the Chronicle | date = August 20, 2008}}</ref>

==See also==
{{Portal|Energy}}
*[[Relative cost of electricity generated by different sources]]
*[[Economics of new nuclear power plants]]
*[[Wind power]]
*[[Renewable energy]]
*[[Nuclear power]]
*[[Solar energy]]
*Hydroelectricity
'''Topics:'''
*[[Environmental concerns with electricity generation]]
*[[Environmental impacts of reservoirs]]
*[[Hydropower]]
*[[Pumped-storage hydroelectricity]]
*[[Run-of-the-river hydroelectricity]]
*[[Small hydro]]
*[[Water power engine]]

'''Lists:'''
*[[List of countries by electricity production from renewable sources]]
*[[List of the largest hydroelectric power stations]]
*[[List of reservoirs and dams]]

'''Categories:'''
*[[:Category:Hydroelectric power stations by country]]

'''Organisations:'''
*[[International Hydropower Association]] (IHA)

== Notes ==
{{Reflist|2}}

== References ==
* {{cite web | url=http://dams.org/report/ | title=Dams and Development – A New Framework for Decision-Making | author=World Commission on Dams | date=November 16, 2000 | accessdate=2009-05-10 }}<!-- report resulting from a cooperation of industry, NGO and (inter) governmental organisations -->
* [http://www.newscientist.com/article.ns?id=dn7046 ''New Scientist'' report on greenhouse gas production by hydroelectric dams.]
* [http://www.waterpowermagazine.com/story.asp?sectioncode=165&storyCode=2019676 ''International Water Power and Dam Construction'' Venezuela country profile]
* [http://www.waterpowermagazine.com/story.asp?sectionCode=165&storyCode=2019652 ''International Water Power and Dam Construction'' Canada country profile]
* [http://www.springer.com/sgw/cda/frontpage/0,,1-10006-22-35070329-0,00.html Tremblay, Varfalvy, Roehm and Garneau. 2005. Greenhouse Gas Emissions - Fluxes and Processes, Springer, 732 p.]

== External links ==
{{Commons category|Hydroelectric power}}
* [http://www.hydropower.org International Hydropower Association]
* {{dmoz|Science/Technology/Energy/Renewable/Hydro/}}
* {{YouTube|id=zmhXNRhNNDI|title=Mechanicville Hydroelectric Station Tour}}
* [http://www.hydro.org National Hydropower Association, USA]
* [http://www.hydroreform.org Hydropower Reform Coalition, USA]
* {{YouTube|id=i9yCpuiMze0|title=Lecture - 10 Hydroelectric Power}} and {{YouTube|id=4LGxEhBmIKw|title=Lecture - 11 Hydroelectric Power}}
* [http://www.dameffects.org Interactive site that demonstrates dams' effects on rivers]
* [http://www.qc.dfo-mpo.gc.ca/iml/en/centres/chip/intro.htm Center of expertise on hydropower impacts on fish and fish habitat, Canada]
* [http://www.hydroquebec.com/en/ Hydro-Québec]
* [http://archives.cbc.ca/IDD-1-75-1750/science_technology/hydro/ CBC Digital Archives – Hydroelectricity: The Power of Water]
* [http://content.lib.washington.edu/ww-spwsweb/index.html University of Washington Libraries – Seattle Power and Water Supply Collection]
* [http://internationalrivers.org/ International Rivers]
* [http://ferc.gov/industries/hydropower.asp United States Federal Energy Regulatory Commission (FERC)]
* [http://www.esha.be European Small Hydropower Association]
* [http://www.nflibrary.ca/nfplindex/specials/power/ Power at Niagara Falls] Niagara Falls Public Library (Ont.)
* [http://www.milfordpowerhouse.com/1/165/Virtual_Tour_of_Milford_Powerhouse.asp Milford Hydroelectric Station Restoration Tour] Built by Henry Ford in 1939
* ''60,000,000 Horsepower Ready to be Harnessed for Work: when these giants are set in action, the real age of electricity will begin and our dreams will become realities'', Popular Science monthly, February 1919, page 46-47, Scanned by Google Books: http://books.google.com/books?id=7igDAAAAMBAJ&pg=PA46

{{Electricity generation|state=show}}
{{Hydropower}}

[[Category:Hydroelectricity| ]]
[[Category:Landscape]]
[[Category:Sustainable technologies]]