Editing Tidal power (section)

{{short description|Technology to convert the energy from tides into useful forms of power}}
[[File:Sihwa Lake Tidal Power Station 01.png|right|thumb|[[Sihwa Lake Tidal Power Station]], located in [[Gyeonggi Province]], South Korea, is the world's largest tidal power installation, with a total power output capacity of 254&nbsp;MW.]]
[[File:Barrage de la Rance.jpg|right|thumb|The [[Rance Tidal Power Station]], in [[Brittany]], northwestern France, was the first large-scale tidal power station (1966), with a total power output capacity of 240 MW]] 
{{Renewable energy sources}}
{{Sustainable energy}}

'''Tidal power''' or '''tidal energy'''  is harnessed by converting energy from [[tide]]s into useful forms of power, mainly electricity using various methods.

Although not yet widely used, tidal energy has the potential for future [[electricity generation]]. Tides are more predictable than [[Wind|the wind]] and [[Sun|the sun]]. Among sources of [[renewable energy]], tidal energy has traditionally suffered from relatively high cost and limited availability of sites with sufficiently high tidal ranges or flow velocities, thus constricting its total availability. However many recent technological developments and improvements, both in design (e.g. [[#Dynamic tidal power|dynamic tidal power]], [[Tidal barrage#Tidal lagoon power|tidal lagoons]]) and turbine technology (e.g. new [[Tidal stream generator#Axial turbines|axial turbines]], [[Tidal stream generator#Vertical and horizontal axis crossflow turbines|cross flow turbines]]), indicate that the total availability of tidal power may be much higher than previously assumed and that economic and [[environmental cost]]s may be brought down to competitive levels.

Historically, [[tide mill]]s have been used both in Europe and on the Atlantic coast of North America.  Incoming water was contained in large storage ponds, and as the tide goes out, it turns waterwheels that use the mechanical power to mill grain.<ref>{{cite web|author=Ocean Energy Council|title=Tidal Energy: Pros for Wave and Tidal Power|url=http://www.oceanenergycouncil.com/index.php/Tidal-Energy/Tidal-Energy.html|archive-url=https://web.archive.org/web/20080513175027/http://www.oceanenergycouncil.com/index.php/Tidal-Energy/Tidal-Energy.html|url-status=dead|archive-date=2008-05-13|date=2011}}</ref> The earliest occurrences date from the [[Middle Ages]], or even from [[Ancient Rome|Roman times]].<ref>{{cite web |url=http://www.kentarchaeology.ac/authors/005.pdf |title=Microsoft Word – RS01j.doc |access-date=2011-04-05 |url-status=live |archive-url=https://web.archive.org/web/20110517013738/http://www.kentarchaeology.ac/authors/005.pdf |archive-date=2011-05-17 }}</ref><ref>{{cite journal| author=Minchinton, W. E. | title=Early Tide Mills: Some Problems | journal=Technology and Culture | volume=20 | issue=4 |date=October 1979 | pages=777–786 | doi=10.2307/3103639| jstor=3103639| s2cid=112337062 }}</ref> The process of using falling water and spinning [[turbine]]s to create electricity was introduced in the U.S. and Europe in the 19th century.<ref>{{cite book|last=Dorf|first=Richard|title=The Energy Factbook|url=https://archive.org/details/energyfactbook00dorf|url-access=registration|date=1981|publisher=McGraw-Hill|location=New York}}</ref>

Electricity generation from marine technologies increased an estimated 16% in 2018, and an estimated 13% in 2019.<ref>{{Cite web|title=Ocean power – Tracking Power 2020 – Analysis|url=https://www.iea.org/reports/tracking-power-2019/ocean-power|access-date=2020-08-25|website=IEA|language=en-GB|archive-date=2020-06-19|archive-url=https://web.archive.org/web/20200619154701/https://www.iea.org/reports/tracking-power-2019/ocean-power|url-status=dead}}</ref> Policies promoting R&D are needed to achieve further cost reductions and large-scale development. The world's first large-scale tidal power plant was France's [[Rance Tidal Power Station]], which became operational in 1966. It was the largest tidal power station in terms of output until [[Sihwa Lake Tidal Power Station]] opened in South Korea in August 2011. The Sihwa station uses sea wall defense barriers complete with 10 turbines generating 254&nbsp;MW.<ref>{{Cite book|title=Guinness world records 2014|last=Glenday|first=Craig|year=2013|publisher=Guinness World Records Limited |isbn=978-1-908843-15-9|url-access=registration|url=https://archive.org/details/guinnessworldrec0000unse_r3e7}}</ref>