Editing Hydropower (section)

==Applications==
[[File:Higashiyama Botanical Garden Shishiodoshi 20170617.gif|thumb|A [[shishi-odoshi]] powered by falling water breaks the quietness of a Japanese garden with the sound of a bamboo rocker arm hitting a rock.]]

===Mechanical power===
====Watermills====
{{excerpt|Watermill}}

====Compressed air ====
{{See also|Trompe}}
A plentiful head of water can be made to generate [[compressed air]] directly without moving parts. In these designs, a falling column of water is deliberately mixed with air bubbles generated through turbulence or a [[Venturi effect|venturi]] pressure reducer at the high-level intake. This allows it to fall down a shaft into a subterranean, high-roofed chamber where the now-compressed air separates from the water and becomes trapped. The height of the falling water column maintains compression of the air in the top of the chamber, while an outlet, submerged below the water level in the chamber allows water to flow back to the surface at a lower level than the intake. A separate outlet in the roof of the chamber supplies the compressed air. A facility on this principle was built on the [[Montreal River (Timiskaming District)|Montreal River]] at Ragged Shutes near [[Cobalt, Ontario]], in 1910 and supplied 5,000 horsepower to nearby mines.<ref>{{cite journal|last=Maynard|first=Frank|date=November 1910|title=Five thousand horsepower from air bubbles|journal=Popular Mechanics|page=633|url={{GBurl|-N0DAAAAMBAJ|p=633}} }}</ref>

===Electricity===
{{Main|Hydroelectricity}}
[[File:Share of electricity production from hydropower.png |thumb|upright=1.6| Share of electricity production from hydropower, 2023<ref>{{cite web |title=Share of electricity production from hydropower |url=https://ourworldindata.org/grapher/share-electricity-hydro |website=Our World in Data |access-date=20 June 2024}}</ref>]]
Hydroelectricity is the biggest hydropower application. Hydroelectricity generates about 15% of global electricity and provides at least 50% of the total electricity supply for more than 35 countries.<ref>{{cite journal |last1=Kaygusuz |first1=K. |title=Hydropower as clean and renewable energy source for electricity generation |journal=Journal of Engineering Research and Applied Science |date=4 June 2016 |volume=5 |issue=1 |pages=359–369 |url=http://journaleras.com/index.php/jeras/article/view/52 }}</ref> In 2021, global installed hydropower electrical capacity reached almost 1400 GW, the highest among all renewable energy technologies.<ref>IEA (2022), Renewables 2022, IEA, Paris https://www.iea.org/reports/renewables-2022, License: CC BY 4.0</ref>

[[Hydroelectricity]] generation starts with converting either the [[potential energy]] of water that is present due to the site's elevation or the [[kinetic energy]] of moving water into electrical energy.{{sfn|Breeze|2019|p={{pn|date=March 2025}}}}

Hydroelectric power plants vary in terms of the way they harvest energy. One type involves a dam and a [[reservoir]]. The water in the reservoir is available on demand to be used to generate electricity by passing through channels that connect the dam to the reservoir. The water spins a turbine, which is connected to the generator that produces electricity.{{sfn|Breeze|2019|p={{pn|date=March 2025}}}}

The other type is called a run-of-river plant. In this case, a barrage is built to control the flow of water, absent a [[reservoir]]. The run-of river power plant needs continuous water flow and therefore has less ability to provide power on demand. The kinetic energy of flowing water is the main source of energy.{{sfn|Breeze|2019|p={{pn|date=March 2025}}}}

Both designs have limitations. For example, dam construction can result in discomfort to nearby residents. The dam and reservoirs occupy a relatively large amount of space that may be opposed by nearby communities.<ref>{{cite book |doi=10.1016/B978-0-12-801027-3.00010-5 |chapter=Hydroelectricity |title=The Future of Energy |date=2014 |last1=Towler |first1=Brian F. |pages=215–235 |isbn=978-0-12-801027-3 }}</ref> Moreover, reservoirs can potentially have major environmental consequences such as harming downstream habitats.{{sfn|Breeze|2019|p={{pn|date=March 2025}}}} On the other hand, the limitation of the run-of-river project is the decreased efficiency of electricity generation because the process depends on the speed of the seasonal river flow. This means that the rainy season increases electricity generation compared to the dry season.<ref>{{cite book |doi=10.1007/978-1-4899-7519-5_8 |chapter=Pumped-storage hydroelectricity |title=Hydropower Economics |series=International Series in Operations Research & Management Science |date=2015 |last1=Førsund |first1=Finn R. |volume=217 |pages=183–206 |isbn=978-1-4899-7518-8 }}</ref>

The size of hydroelectric plants can vary from small plants called [[micro hydro]], to large plants that supply power to a whole country. As of 2019, the [[List of largest power stations|five largest power stations in the world]] are conventional hydroelectric power stations with dams.<ref>{{cite book |last=Davis |first=Scott |author-link= |date=2003 |title=Microhydro: Clean Power from Water |url= |location=Gabriola Island, British Columbia |publisher=New Society Publishers |page= |isbn=978-0-86571-484-7 }}</ref>

Hydroelectricity can also be used to store energy in the form of [[potential energy]] between two reservoirs at different heights with [[pumped-storage hydroelectricity|pumped-storage]]. Water is pumped uphill into reservoirs during periods of low demand to be released for generation when demand is high or system generation is low.<ref>{{cite book |doi=10.1016/B0-12-176480-X/00104-2 |chapter=Storage of Energy, Overview |title=Encyclopedia of Energy |date=2004 |last1=Semadeni |first1=Marco |pages=719–738 |isbn=978-0-12-176480-7 }}</ref>

Other forms of electricity generation with hydropower include [[tidal stream generator]]s using energy from [[tidal power]] generated from oceans, rivers, and human-made canal systems to generating electricity.{{sfn|Breeze|2019|p={{pn|date=March 2025}}}}<gallery mode="packed">
File:Hydroelectric dam.svg|A [[Hydroelectricity#Generating methods|conventional]] dammed-hydro facility (hydroelectric dam) is the most common type of hydroelectric power generation.
File:Chief Joseph Dam.jpg|[[Chief Joseph Dam]] near [[Bridgeport, Washington]], is a major [[Run-of-the-river hydroelectricity|run-of-the-river station]] without a sizeable reservoir.
File:Nw vietnam hydro.jpg|[[Micro hydro]] in Northwest Vietnam
File:Stwlan.dam.jpg|The upper reservoir and dam of the [[Ffestiniog Power Station|Ffestiniog Pumped Storage Scheme]] in [[Wales]]. The lower power station can generate 360&nbsp;MW of electricity.
</gallery>