Editing Renewable energy (section)

=== Hydropower ===
{{Main|Hydroelectricity|Hydropower|}}

[[File:ThreeGorgesDam-China2009.jpg|thumb|The [[Three Gorges Dam]] for [[hydropower]] on the [[Yangtze River]] in China]]
[[File:Three gorges dam from space.jpg|thumb|[[Three Gorges Dam]] and [[Gezhouba Dam]], China]]
{| class="wikitable"
! Installed capacity and other key design parameters
! Value and year
|-
| Global electricity power generation capacity || 1,267.9 GW (2023)<ref>{{harvnb|IRENA|2024|p=9}}. Note: Excludes pure pumped storage.</ref>
|-
| Global electricity power generation capacity annual growth rate || 1.9% (2014-2023)<ref>{{harvnb|IRENA|2024|p=9}}. Note: Excludes pure pumped storage. Compound annual growth rate 2014-2023.</ref>
|-
| Share of global electricity generation || 14.3% (2023)<ref name="Ember 2024">{{cite web |date=8 May 2024 |title=Global Electricity Review 2024 |url=https://ember-energy.org/latest-insights/global-electricity-review-2024/ |access-date=8 May 2024 |publisher=[[Ember (non-profit organisation)|Ember]]}}</ref>
|-
| Levelized cost per megawatt hour || USD 65.581 (2019){{sfn|NREL ATB|2021|loc=Hydropower}}
|-
| Primary technology || [[Hydroelectricity#Generating methods|Dam]]
|-
| Main applications || Electricity, [[Pumped-storage hydroelectricity|pumped storage]], [[Hydropower#Mechanical power|mechanical power]]
|}

Since water is about 800 times [[Density of air|denser than air]], even a slow flowing stream of water, or moderate sea [[Swell (ocean)|swell]], can yield considerable amounts of energy. Water can generate electricity with a [[Energy conversion efficiency|conversion efficiency]] of about 90%, which is the highest rate in renewable energy.<ref name="Ang">{{cite journal |last1=Ang |first1=Tze-Zhang |last2=Salem |first2=Mohamed |last3=Kamarol |first3=Mohamad |last4=Das |first4=Himadry Shekhar |last5=Nazari |first5=Mohammad Alhuyi |last6=Prabaharan |first6=Natarajan |title=A comprehensive study of renewable energy sources: Classifications, challenges and suggestions |journal=Energy Strategy Reviews |date=2022 |volume=43 |pages=100939 |doi=10.1016/j.esr.2022.100939 |s2cid=251889236 |language=en |issn=2211-467X |doi-access=free|bibcode=2022EneSR..4300939A }}</ref> There are many forms of water energy:
* Historically, hydroelectric power came from constructing large hydroelectric dams and reservoirs, which are still popular in [[Developing country|developing countries]].<ref>{{Cite journal|last1=Moran |first1=Emilio F. |last2=Lopez|first2=Maria Claudia|last3=Moore|first3=Nathan|last4=Müller|first4=Norbert |last5=Hyndman|first5=David W.|date=2018|title=Sustainable hydropower in the 21st century |journal=Proceedings of the National Academy of Sciences|volume=115|issue=47|pages=11891–11898 |doi=10.1073/pnas.1809426115|pmid=30397145|issn=0027-8424|pmc=6255148|bibcode=2018PNAS..11511891M |doi-access=free}}</ref> The [[List of largest hydroelectric power stations|largest]] of them are the [[Three Gorges Dam]] (2003) in [[China]] and the [[Itaipu Dam]] (1984) built by Brazil and Paraguay.
* [[Small hydro]] systems are hydroelectric power installations that typically produce up to {{nowrap|50 MW}} of power. They are often used on small rivers or as a low-impact development on larger rivers. China is the largest producer of hydroelectricity in the world and has more than 45,000 small hydro installations.<ref>{{cite web |url=https://www.irena.org/DocumentDownloads/Publications/RE_Technologies_Cost_Analysis-HYDROPOWER.pdf |title=DocHdl2OnPN-PRINTRDY-01tmpTarget |access-date=26 March 2019 |archive-date=9 November 2018 |archive-url=https://web.archive.org/web/20181109085415/https://www.irena.org/documentdownloads/publications/re_technologies_cost_analysis-hydropower.pdf |url-status=dead }}</ref>
* [[Run-of-the-river hydroelectricity]] plants derive energy from rivers without the creation of a large [[reservoir]]. The water is typically conveyed along the side of the river valley (using channels, pipes or tunnels) until it is high above the valley floor, whereupon it can be allowed to fall through a penstock to drive a turbine. A run-of-river plant may still produce a large amount of electricity, such as the [[Chief Joseph Dam]] on the Columbia River in the United States.<ref>{{cite web|title=Run-of-the-river hydroelectricity|url=https://energyeducation.ca/encyclopedia/Run-of-the-river_hydroelectricity |last=Afework|first=Bethel|date=3 September 2018|work=Energy Education|access-date=27 April 2019|archive-url=https://web.archive.org/web/20190427184803/https://energyeducation.ca/encyclopedia/Run-of-the-river_hydroelectricity|archive-date=27 April 2019|url-status=live}}</ref> However many run-of-the-river hydro power plants are [[micro hydro]] or [[pico hydro]] plants.

Much hydropower is flexible, thus complementing wind and solar, as it not intermittent.<ref>{{Cite web |title=Net zero: International Hydropower Association |url=https://www.hydropower.org/net-zero |access-date=2022-06-24 |website=www.hydropower.org |language=en}}</ref> In 2021, the world renewable hydropower capacity was 1,360 GW.<ref name="IEA-3" /> Only a third of the world's estimated hydroelectric potential of 14,000 TWh/year has been developed.<ref name="iha2021">{{cite web |date=11 June 2021 |title=Hydropower Status Report |url=https://www.hydropower.org/status-report |url-status=dead |archive-url=https://web.archive.org/web/20230403212029/https://www.hydropower.org/status-report |archive-date=3 April 2023 |access-date=30 May 2022 |website=International Hydropower Association}}</ref><ref name="etp2006">{{cite book |url=https://www.iea.org/reports/energy-technology-perspectives-2006 |title=Energy Technology Perspectives: Scenarios and Strategies to 2050 |date=2006 |publisher=International Energy Agency |isbn=926410982X |location=Paris |pages=124 |access-date=30 May 2022}}</ref> New hydropower projects face opposition from local communities due to their large impact, including relocation of communities and flooding of wildlife habitats and farming land.<ref>{{Cite web |title=Environmental Impacts of Hydroelectric Power {{!}} Union of Concerned Scientists |url=https://www.ucsusa.org/resources/environmental-impacts-hydroelectric-power |url-status=live |archive-url=https://web.archive.org/web/20210715234227/https://www.ucsusa.org/resources/environmental-impacts-hydroelectric-power |archive-date=15 July 2021 |access-date=9 July 2021 |website=www.ucsusa.org}}</ref> High cost and lead times from permission process, including environmental and risk assessments, with lack of environmental and social acceptance are therefore the primary challenges for new developments.<ref>{{Cite web |title=Hydropower Special Market Report |url=https://iea.blob.core.windows.net/assets/4d2d4365-08c6-4171-9ea2-8549fabd1c8d/HydropowerSpecialMarketReport_corr.pdf |url-status=live |archive-url=https://web.archive.org/web/20210707021807/https://iea.blob.core.windows.net/assets/4d2d4365-08c6-4171-9ea2-8549fabd1c8d/HydropowerSpecialMarketReport_corr.pdf |archive-date=7 July 2021 |access-date=9 July 2021 |website=IEA |pages=34–36}}</ref> It is popular to repower old dams thereby increasing their efficiency and capacity as well as quicker responsiveness on the grid.<ref>{{cite web |author1=L. Lia |author2=T. Jensen |author3=K.E. Stensbyand |author4=G. Holm |author5=A.M. Ruud |title=The current status of hydropower development and dam construction in Norway |url=https://www.ntnu.no/documents/381182060/641036380/Leif+Lia_FINAL.PDF/32bac8f3-b443-493b-a1eb-e22ce572acd9 |url-status=live |archive-url=https://web.archive.org/web/20170525165854/https://www.ntnu.no/documents/381182060/641036380/Leif+Lia_FINAL.PDF/32bac8f3-b443-493b-a1eb-e22ce572acd9 |archive-date=25 May 2017 |access-date=26 March 2019 |website=Ntnu.no |format=PDF}}</ref> Where circumstances permit existing dams such as the [[Richard B. Russell Dam|Russell Dam]] built in 1985 may be updated with "pump back" facilities for [[pumped-storage hydroelectricity|pumped-storage]] which is useful for peak loads or to support intermittent wind and solar power. Because [[Dispatchable generation|dispatchable power]] is more valuable than VRE<ref>{{Cite web |date=2021-04-19 |title=How Norway became Europe's biggest power exporter |url=https://www.power-technology.com/analysis/how-norway-became-europes-biggest-power-exporter/ |url-status=dead |archive-url=https://web.archive.org/web/20220627153206/https://www.power-technology.com/analysis/how-norway-became-europes-biggest-power-exporter/ |archive-date=27 June 2022 |access-date=2022-06-27 |website=Power Technology |language=en-US}}</ref><ref>{{Cite web |date=17 January 2022 |title=Trade surplus soars on energy exports {{!}} Norway's News in English — www.newsinenglish.no |url=https://www.newsinenglish.no/2022/01/17/trade-surplus-soars-on-energy-exports/ |access-date=2022-06-27 |language=en-US}}</ref> countries with large hydroelectric developments such as Canada and Norway are spending billions to expand their grids to trade with neighboring countries having limited hydro.<ref>{{cite web |title=New Transmission Line Reaches Milestone |url=http://www.vpr.net/news_detail/88975/new-transmission-line-reaches-milestone/ |url-status=live |archive-url=https://web.archive.org/web/20170203164110/http://www.vpr.net/news_detail/88975/new-transmission-line-reaches-milestone/ |archive-date=3 February 2017 |access-date=3 February 2017 |website=Vpr.net}}</ref>