View source for Geothermal energy

{{short description|Thermal energy generated and stored in the Earth}}
{{about|thermal energy generated and stored deep in the earth|information about heat pumps used to extract heat from near the surface|ground source heat pump}}
[[File:NesjavellirPowerPlant edit2.jpg|thumb|upright=1.3|Steam rising from the [[Nesjavellir Geothermal Power Station]] in [[Iceland]]]]
[[File: Geothermal Energy Plant.jpg|upright=1.3|thumb|The [[Imperial Valley Geothermal Project]] near the [[Salton Sea]], California]]
{{renewable energy}}

'''Geothermal energy''' is [[thermal energy]] extracted from the Earth's [[crust (geology)|crust]]. It combines energy from the formation of the planet and from [[radioactive decay]]. Geothermal energy has been exploited as a source of heat and/or electric power for millennia.

[[Geothermal heating]], using water from [[hot springs]], for example, has been used for bathing since [[Paleolithic]] times and for [[space heating]] since Roman times. [[Geothermal power]] (generation of electricity from geothermal energy), has been used since the 20th century. Geothermal power plants produce power at a constant rate, without regard to weather conditions. Geothermal resources are theoretically more than adequate to supply humanity's energy needs. Most extraction occurs in areas near [[tectonic plate boundaries]].

The cost of generating geothermal power decreased by 25% during the 1980s and 1990s.<ref>{{Citation|last=Cothran|first=Helen|title=Energy Alternatives|year=2002|publisher=Greenhaven Press|isbn=978-0-7377-0904-9|url-access=registration|url=https://archive.org/details/energyalternativ00hele}}{{page needed|date=February 2014}}</ref> Technological advances continued to reduce costs and thereby expand the amount of viable resources. In 2021, the US Department of Energy estimated that power from a newly built plant costs about $0.05/kWh.<ref>{{Cite web|title=Geothermal FAQs|url=https://www.energy.gov/eere/geothermal/geothermal-faqs|access-date=2021-06-25|website=Energy.gov|language=en}}</ref>

In 2019, 13,900 [[megawatts]] (MW) of geothermal power was available worldwide.<ref>{{Cite web|title=Renewables 2020: Global Status Report. Chapter 01; Global Overview|url=https://www.ren21.net/gsr-2020 |publisher=REN21 |access-date=2021-02-02|language=en}}</ref> An additional 28 gigawatts provided heat for district heating, space heating, spas, industrial processes, desalination, and agricultural applications as of 2010.<ref name="IPCC">
{{Cite journal|first1=Ingvar B. |last1=Fridleifsson |first2=Ruggero |last2=Bertani |first3=Ernst |last3=Huenges |first4=John W. |last4=Lund |first5=Arni |last5=Ragnarsson |first6=Ladislaus |last6=Rybach |date=2008-02-11 |title=The possible role and contribution of geothermal energy to the mitigation of climate change |journal=IPCC Scoping Meeting on Renewable Energy Sources conference, Proceedings |editor=O. Hohmeyer and T. Trittin |publisher=The Intergovernmental Panel on Climate Change|location=Luebeck, Germany |pages=59–80 |url=http://www.iea-gia.org/documents/FridleifssonetalIPCCGeothermalpaper2008FinalRybach20May08_000.pdf |access-date=2009-04-06 |archive-url=https://web.archive.org/web/20100308014920/http://www.iea-gia.org/documents/FridleifssonetalIPCCGeothermalpaper2008FinalRybach20May08_000.pdf |archive-date=March 8, 2010}}</ref> As of 2019 the industry employed about one hundred thousand people.<ref>{{Cite web|title=IRENA – Global geothermal workforce reaches 99,400 in 2019|url=https://www.thinkgeoenergy.com/irena-global-geothermal-workforce-reaches-99400-in-2019/|access-date=2020-10-04|website=Think GeoEnergy - Geothermal Energy News|date=2 October 2020 |language=en-US}}</ref>

The adjective ''geothermal'' originates from the Greek roots {{Lang|grc|γῆ}} ({{Lang|grc-Latn|gê}}), meaning the Earth, and {{Lang|grc|θερμός}} ({{Lang|grc-Latn|thermós}}), meaning hot.

{{Toclimit}}

== History ==
[[File:Oldest geothermal.jpg|thumb|right|The oldest known pool fed by a hot spring, built in the [[Qin dynasty]] in the 3rd century BC]]
[[Hot spring]]s have been used for bathing since at least [[Paleolithic]] times.<ref>{{Citation| last =Cataldi| first =Raffaele| date =August 1992| title =Review of historiographic aspects of geothermal energy in the Mediterranean and Mesoamerican areas prior to the Modern Age| periodical =Geo-Heat Centre Quarterly Bulletin| location =Klamath Falls, Oregon| publisher =Oregon Institute of Technology| volume =18| issue =1| pages =13–16| url =http://geoheat.oit.edu/pdf/bulletin/bi046.pdf| access-date =2009-11-01| archive-date =2010-06-18| archive-url =https://web.archive.org/web/20100618001239/http://geoheat.oit.edu/pdf/bulletin/bi046.pdf}}</ref> The [[Huaqing Pool|oldest known spa]] is at the site of the Huaqing Chi palace. In the first century CE, Romans conquered ''[[Aquae Sulis]]'', now [[Bath, Somerset]], England, and used the hot springs there to supply [[thermae|public baths]] and [[hypocaust|underfloor heating]]. The admission fees for these baths probably represent the first commercial use of geothermal energy. The world's oldest geothermal district heating system, in [[Chaudes-Aigues]], France, has been operating since the 15th century.<ref name="utilization">{{Citation| last =Lund| first =John W.| date =June 2007| title =Characteristics, Development and utilization of geothermal resources| periodical =Geo-Heat Centre Quarterly Bulletin| location =Klamath Falls, Oregon| publisher =Oregon Institute of Technology| volume =28| issue =2| pages =1–9| url =http://geoheat.oit.edu/bulletin/bull28-2/art1.pdf| access-date =2009-04-16| archive-date =2010-06-17| archive-url =https://web.archive.org/web/20100617215822/http://geoheat.oit.edu/bulletin/bull28-2/art1.pdf}}</ref> The earliest industrial exploitation began in 1827 with the use of [[geyser]] steam to extract [[boric acid]] from [[volcanic mud]] in [[Larderello]], Italy.

In 1892, the US's first [[district heating]] system in [[Boise, Idaho]] was powered by geothermal energy. It was copied in [[Klamath Falls, Oregon]], in 1900. The world's first known building to utilize geothermal energy as its primary heat source was the [[Hot Lake Hotel]] in [[Union County, Oregon]], beginning in 1907.<ref>{{Citation |last=Cleveland |first=Cutler J. |title=Preface to the First Edition |date=2015 |encyclopedia=Dictionary of Energy |publisher=Elsevier|page=291|doi=10.1016/b978-0-08-096811-7.50035-4 |isbn=978-0-08-096811-7 }}</ref> A geothermal well was used to heat [[greenhouses]] in Boise in 1926, and geysers were used to heat greenhouses in Iceland and [[Tuscany]] at about the same time.<ref name="Dickson">{{Citation
 |last1 = Dickson
 |first1 = Mary H.
 |last2 = Fanelli
 |first2 = Mario
 |date = February 2004
 |title = What is Geothermal Energy?
 |publisher = Istituto di Geoscienze e Georisorse
 |location = Pisa, Italy
 |url = http://www.geothermal-energy.org/314,what_is_geothermal_energy.html
 |access-date = 2010-01-17
 |archive-url = https://web.archive.org/web/20110726100731/http://www.geothermal-energy.org/314,what_is_geothermal_energy.html
 |archive-date = 2011-07-26
 }}</ref> Charles Lieb developed the first [[downhole heat exchanger]] in 1930 to heat his house. Geyser steam and water began heating homes in Iceland in 1943.

[[File:geothermal capacity.svg|thumb|left|Global geothermal electric capacity. Upper red line is installed capacity;<ref name="Bertani">{{Citation
| last =Bertani | first =Ruggero | date =September 2007
| title =World Geothermal Generation in 2007
| periodical =Geo-Heat Centre Quarterly Bulletin
| location =Klamath Falls, Oregon
| publisher =Oregon Institute of Technology
| volume =28
| issue =3
| pages =8–19
| url =http://geoheat.oit.edu/bulletin/bull28-3/art3.pdf
| access-date =2009-04-12
}}</ref> lower green line is realized production.<ref name="IPCC" />]]

In the 20th century, geothermal energy came into use as a generating source. Prince [[Piero Ginori Conti]] tested the first geothermal power generator on 4 July 1904, at the Larderello steam field. It successfully lit four light bulbs.<ref>{{Citation
 |author1=Tiwari, G. N. |author2=Ghosal, M. K. |title=Renewable Energy Resources: Basic Principles and Applications
 |publisher=Alpha Science
 |year=2005
 |isbn=978-1-84265-125-4
}}{{page needed|date=February 2014}}</ref> In 1911, the world's first commercial geothermal power plant was built there. It was the only industrial producer of geothermal power until New Zealand built a plant in 1958. In 2012, it produced some 594 megawatts.<ref name=sci2013>{{Citation |doi=10.1126/science.1235640|pmid = 23704561|title = More Power from Below|journal = Science|volume = 340|issue = 6135|pages = 933–4|year = 2013|last1 = Moore|first1 = J. N.|last2 = Simmons|first2 = S. F.|s2cid = 206547980|bibcode = 2013Sci...340..933M}}</ref>

In 1960, [[Pacific Gas and Electric]] began operation of the first US geothermal power plant at [[The Geysers]] in California.<ref name="100years">{{Citation |last=Lund |first=J. |title=100 Years of Geothermal Power Production |date=September 2004 |periodical=Geo-Heat Centre Quarterly Bulletin |volume=25 |issue=3 |pages=11–19 |url=http://geoheat.oit.edu/bulletin/bull25-3/art2.pdf |access-date=2009-04-13 |archive-url=https://web.archive.org/web/20100617221828/http://geoheat.oit.edu/bulletin/bull25-3/art2.pdf |archive-date=2010-06-17 |location=Klamath Falls, Oregon |publisher=Oregon Institute of Technology}}</ref> The original turbine lasted for more than 30&nbsp;years and produced 11&nbsp;[[Megawatt|MW]] net power.<ref>{{Citation
 |last1 = McLarty
 |first1 = Lynn
 |last2 = Reed
 |first2 = Marshall J.
 |title = The US Geothermal Industry: Three Decades of Growth
 |journal = Energy Sources, Part A
 |volume = 14
 |issue = 4
 |pages = 443–455
 |year = 1992
 |url = http://geotherm.inel.gov/publications/articles/mclarty/mclarty-reed.pdf
 |doi = 10.1080/00908319208908739
 |access-date = 2009-11-05
 |archive-url = http://arquivo.pt/wayback/20160516221028/http://geotherm.inel.gov/publications/articles/mclarty/mclarty%2Dreed.pdf
 |archive-date = 2016-05-16
 }}</ref>

An organic fluid based binary cycle power station was first demonstrated in 1967 in the [[USSR]]<ref name="100years" /> and later introduced to the US in 1981{{Citation needed|date=September 2024}}.  This technology allows the use of temperature resources as low as 81&nbsp;°C. In 2006, a binary cycle plant in [[Chena Hot Springs, Alaska]], came on-line, producing electricity from a record low temperature of {{convert|57|C}}.<ref name="Chena">
{{Citation
 | title = Understanding the Chena Hot flopë Springs, Alaska, geothermal system using temperature and pressure data
 | year = 2008
 | journal = Geothermics
 | pages = 565–585
 | volume = 37
 | issue = 6
 | last1 = Erkan | first1 = K.
 | last2 = Holdmann | first2 = G.
 | last3 = Benoit | first3 = W.
 | last4 = Blackwell | first4 = D.
 | doi = 10.1016/j.geothermics.2008.09.001
}}</ref>

==Resources==
[[File:EGS diagram.svg|thumb|left|'''Enhanced geothermal system''' 1:Reservoir 2:Pump&nbsp;house 3:Heat&nbsp;exchanger 4:Turbine&nbsp;hall 5:Production&nbsp;well 6:Injection&nbsp;well 7:Hot water to district heating 8:Porous&nbsp;sediments 9:Observation&nbsp;well 10:Crystalline&nbsp;bedrock]]

The Earth has an internal heat content of [[1 E31 J|10<sup>31</sup>&nbsp;joules]] (3·10<sup>15</sup>&nbsp;[[TWh]]), About 20% of this is residual heat from [[planetary accretion]]; the remainder is attributed to past and current [[radioactive decay]] of [[Naturally occurring radioactive material|naturally occurring isotopes]].<ref name="turcotte">
{{Citation |last=Turcotte |first=D. L. |title=Geodynamics |pages=7-8 |year=2002 |edition=2 |location=Cambridge, England, UK |publisher=Cambridge University Press |isbn=978-0-521-66624-4 |author2=Schubert, G.}}</ref> For example, a 5275 m deep borehole in United Downs Deep Geothermal Power Project in [[Cornwall]], England, found granite with very high [[thorium]] content, whose [[radioactive decay]] is believed to power the high temperature of the rock.<ref>{{Cite web |title=United Downs – Geothermal Engineering Ltd |url=https://geothermalengineering.co.uk/united-downs/ |access-date=2021-07-05 |language=en-GB |archive-date=2022-03-08 |archive-url=https://web.archive.org/web/20220308085807/https://geothermalengineering.co.uk/united-downs/ }}</ref>

Earth's interior temperature and pressure are high enough to cause some rock to melt and the solid [[mantle (geology)|mantle]] to behave plastically. Parts of the [[mantle convection|mantle convect]] upward since it is lighter than the surrounding rock. Temperatures at the [[core–mantle boundary]] can reach over {{convert|4000|°C|°F|abbr=on}}.<ref>{{citation |last1=Lay |first1=Thorne |title=Core–mantle boundary heat flow |journal=Nature Geoscience |volume=1 |issue=1 |pages=25–32 |year=2008 |bibcode=2008NatGe...1...25L |doi=10.1038/ngeo.2007.44 |last2=Hernlund |first2=John |last3=Buffett |first3=Bruce A.}}</ref>

The Earth's internal thermal energy [[heat flux|flows to the surface by conduction]] at a rate of 44.2 [[terawatts]] (TW),<ref name="pollack_et_al">{{cite journal
| last = Pollack | first = H.N.
 |author2=S. J. Hurter |author3=J. R. Johnson
| year = 1993
| title = Heat Flow from the Earth's Interior: Analysis of the Global Data Set
| volume = 30
| issue = 3
| pages = 267–280
| journal = Rev. Geophys.
| doi = 10.1029/93RG01249
|bibcode = 1993RvGeo..31..267P }}</ref> and is replenished by radioactive decay of minerals at a rate of 30&nbsp;TW.<ref name="sustainability">{{cite journal
| last =Rybach
| first =Ladislaus
| date =September 2007
| title =Geothermal Sustainability
| periodical =Geo-Heat Centre Quarterly Bulletin
| location =Klamath Falls, Oregon
| publisher =Oregon Institute of Technology
| volume =28
| issue =3
| pages =2–7
| url =http://geoheat.oit.edu/bulletin/bull28-3/art2.pdf
| access-date =2009-05-09
| archive-date =2012-02-17
| archive-url =https://web.archive.org/web/20120217184740/http://geoheat.oit.edu/bulletin/bull28-3/art2.pdf
}}</ref> These power rates are more than double humanity's current energy consumption from all primary sources, but most of this energy flux is not recoverable. In addition to the internal heat flows, the top layer of the surface to a depth of {{convert|10|m|ft|abbr=on}} is heated by solar energy during the summer, and cools during the winter.

Outside of the seasonal variations, the [[geothermal gradient]] of temperatures through the crust is {{convert|25|–|30|C|F}} per km of depth in most of the world. The conductive heat [[flux]] averages 0.1&nbsp;MW/km<sup>2</sup>. These values are much higher near tectonic plate boundaries where the crust is thinner. They may be further augmented by combinations of fluid circulation, either through [[magma conduit]]s, [[hot springs]], [[hydrothermal circulation]].

The thermal efficiency and profitability of electricity generation is particularly sensitive to temperature. Applications receive the greatest benefit from a high natural heat flux most easily from a [[hot spring]]. The next best option is to drill a well into a hot [[aquifer]]. An artificial hot water reservoir may be built by injecting water to [[hydraulically fracture]] bedrock. The systems in this last approach are called [[enhanced geothermal systems]].<ref name="INEL">{{Citation
 |last = Tester
 |first = Jefferson W.
 |title = The Future of Geothermal Energy
 |volume = Impact of Enhanced Geothermal Systems (Egs) on the United States in the 21st Century: An Assessment
 |publisher = Idaho National Laboratory, [[Massachusetts Institute of Technology]]
 |location = Idaho Falls
 |isbn = 978-0-615-13438-3
 |pages = 1–8 to 1–33 (Executive Summary)
 |url = http://geothermal.inel.gov/publications/future_of_geothermal_energy.pdf
 |access-date = 2007-02-07
 |year = 2006
 |display-authors = etal
 |archive-url = https://wayback.archive-it.org/all/20110310030646/http://geothermal.inel.gov/publications/future_of_geothermal_energy.pdf
 |archive-date = 2011-03-10
 }}</ref>

2010 estimates of the potential for electricity generation from geothermal energy vary widely, from {{gaps|0.035|to|2|TW}} depending on the scale of investments.<ref name="IPCC"/> Upper estimates of geothermal resources assume wells as deep as {{convert|10|km|mi|0}}, although 20th century wells rarely reached more than {{convert|3|km|mi|0}} deep.<ref name="IPCC" /> Wells of this depth are common in the petroleum industry.<ref>{{Cite journal|url=https://www.e3s-conferences.org/articles/e3sconf/abs/2018/35/e3sconf_usme2018_00006/e3sconf_usme2018_00006.html|title=Resource evaluation of geothermal power plant under the conditions of carboniferous deposits usage in the Dnipro-Donetsk depression|first1=Mykhailo|last1=Fyk|first2=Volodymyr|last2=Biletskyi|first3=Mokhammed|last3=Abbud|date=May 25, 2018|journal=E3S Web of Conferences|volume=60|page=00006|via=www.e3s-conferences.org|doi=10.1051/e3sconf/20186000006|bibcode=2018E3SWC..6000006F|doi-access=free}}</ref> 
{{clear left}}

==Geothermal power==
{{Main|Geothermal power}}
<!-- Deleted image removed: [[File:Installed energy capacity (geothermal).png|thumb|upright=1.6|Installed geothermal energy capacity, 2024<ref>{{cite web |title=Installed geothermal energy capacity |url=https://ourworldindata.org/grapher/installed-geothermal-capacity |website=Our World in Data |access-date=18 July 2025}}</ref>]] -->
Geothermal power is [[electricity generation|electrical power generated]] from geothermal energy. Dry steam, flash steam, and binary cycle power stations have been used for this purpose. As of 2010 geothermal electricity was generated in 26 countries.<ref name="gea2010">Geothermal Energy Association. [http://www.geo-energy.org/pdf/reports/GEA_International_Market_Report_Final_May_2010.pdf Geothermal Energy: International Market Update] {{Webarchive|url=https://web.archive.org/web/20170525165514/http://www.geo-energy.org/pdf/reports/GEA_International_Market_Report_Final_May_2010.pdf |date=2017-05-25 }} May 2010, p. 4-6.</ref><ref name=":1">{{Cite book|last1=Bassam|first1=Nasir El |last2=Maegaard|first2=Preben |last3=Schlichting|first3=Marcia |url={{google books|plainurl=y|id=uP4eGFt4c_AC|page=187}}|title=Distributed Renewable Energies for Off-Grid Communities: Strategies and Technologies Toward Achieving Sustainability in Energy Generation and Supply|date=2013|publisher=Newnes|isbn=978-0-12-397178-4|page=187|language=en}}</ref>

As of 2019, worldwide geothermal power capacity amounted to 15.4 [[gigawatt]]s (GW), of which 23.86 percent or 3.68 GW were in the [[geothermal energy in the United States|United States]].<ref name="2019 Capacity">{{cite news|last=Richter|first=Alexander|url=https://www.thinkgeoenergy.com/the-top-10-geothermal-countries-2019-based-on-installed-generation-capacity-mwe/|title=The Top 10 Geothermal Countries 2019 – based on installed generation capacity (MWe)|publisher=Think GeoEnergy – Geothermal Energy News|date=27 January 2020|language=en-US|access-date=19 February 2021}}</ref>

Geothermal energy supplies a significant share of the electrical power in [[geothermal power in Iceland|Iceland]], [[geothermal power in El Salvador|El Salvador]], [[geothermal power in Kenya|Kenya]], the [[geothermal power in the Philippines|Philippines]] and [[New Zealand]].<ref name=":0">{{cite book|url=https://www.icebookshop.com/Products/Geothermal-Energy,-Heat-Exchange-Systems-and-Energ.aspx|title=Geothermal Energy, Heat Exchange Systems and Energy Piles|last1=Craig|first1=William|last2=Gavin|first2=Kenneth|publisher=ICE Publishing|year=2018|isbn=978-0-7277-6398-3|location=London|pages=41–42|archive-date=2018-08-21|access-date=2021-07-01|archive-url=https://web.archive.org/web/20180821191853/https://www.icebookshop.com/Products/Geothermal-Energy,-Heat-Exchange-Systems-and-Energ.aspx}}</ref>

Geothermal power is considered to be a [[renewable energy|renewable]] energy because heat extraction rates are insignificant compared to the [[Earth's internal heat budget|Earth's heat content]].<ref name="sustainability" /> The [[life-cycle greenhouse-gas emissions of energy sources|greenhouse gas emissions]] of geothermal electric stations are on average 45&nbsp;grams of [[carbon dioxide]] per kilowatt-hour of electricity, or less than 5 percent of that of coal-fired plants.<ref name="IPCC Annex II">{{cite web|last1=Moomaw |first1=W. |first2=P. |last2=Burgherr |first3=G. |last3=Heath |first4=M. |last4=Lenzen |first5=J. |last5=Nyboer |first6=A. |last6=Verbruggen|url=http://srren.ipcc-wg3.de/report/IPCC_SRREN_Annex_II.pdf |title=2011: Annex II: Methodology|work=IPCC: Special Report on Renewable Energy Sources and Climate Change Mitigatio|page= 10}}</ref>

Geothermal electric plants were traditionally built on the edges of tectonic plates where high-temperature geothermal resources approach the surface. The development of [[binary cycle power plant]]s and improvements in drilling and extraction technology enable [[enhanced geothermal systems]] over a greater geographical range.<ref name="INEL" /> Demonstration projects are operational in [[Landau-Pfalz]], Germany, and [[Soultz-sous-Forêts]], France, while an earlier effort in [[Basel]], Switzerland, was shut down [[Induced seismicity in Basel|after it triggered earthquakes]]. Other demonstration projects are under construction in [[Geothermal power in Australia|Australia]], the [[United Kingdom]], and the US.<ref>
{{Cite journal |last=Bertani |first=Ruggero |year=2009 |title=Geothermal Energy: An Overview on Resources and Potential |url=http://pangea.stanford.edu/ERE/pdf/IGAstandard/ISS/2009Slovakia/I.1.Bertani.pdf |journal=Proceedings of the International Conference on National Development of Geothermal Energy Use |editor-last1=Popovski |editor-first1=K. |editor-last2=Vranovska |editor-first2=A. |editor-last3=Popovska Vasilevska |editor-first3=S.}}</ref> In [[Myanmar]] over 39 locations are capable of geothermal power production, some of which are near [[Yangon]].<ref>{{Citation |last=DuByne |first=David |title=Geothermal Energy in Myanmar Securing Electricity for Eastern Border Development |date=November 2015 |journal=Myanmar Business Today Magazine |pages=6–8 |url=http://www.oilseedcrops.org/wp-content/uploads/2015/11/Geothermal-Energy-in-Myanmar-Securing-Electricity-for-Eastern-Border-Development-David-DuByne.pdf}}</ref>

{| class="wikitable sortable floatright" style="text-align:right;"
|+ Direct use data 2015
!scope="col"| Country
!scope="col"| Capacity (MW) 2015<ref>{{Citation| last1 =Lund | first1 =John W. | last2 =Boyd | first2 =Tonya L.| date =April 2015| title =Direct Utilization of Geothermal Energy 2015 Worldwide Review| periodical =Proceedings World Geothermal Congress 2015| volume =60 | page =66 | doi =10.1016/j.geothermics.2015.11.004 | bibcode =2016Geoth..60...66L | url = https://pangea.stanford.edu/ERE/db/WGC/papers/WGC/2015/01000.pdf| access-date =2015-04-27}}</ref>
|-
!scope="row"| [[Geothermal energy in the United States|United States]]
|17,415{{0|.00}}
|-
!scope="row"| [[Geothermal power in the Philippines|Philippines]]
|3{{0|.00}}
|-
!scope="row"| [[Geothermal power in Indonesia|Indonesia]]
|2{{0|.00}}
|-
!scope="row"| [[Geothermal power in Mexico|Mexico]]
|155{{0|.00}}
|-
!scope="row"| [[Geothermal power in Italy|Italy]]
|1,014{{0|.00}}
|-
!scope="row"| [[Geothermal power in New Zealand|New Zealand]]
|487{{0|.00}}
|-
!scope="row"| [[Geothermal power in Iceland|Iceland]]
|2,040{{0|.00}}
|-
!scope="row"| [[Geothermal power in Japan|Japan]]
|2,186{{0|.00}}
|-
!scope="row"| [[Geothermal energy in Iran|Iran]]
|81{{0|.00}}
|-
!scope="row"| [[Geothermal energy in El Salvador|El Salvador]]
|3{{0|.00}}
|-
!scope="row"| [[Geothermal power in Kenya|Kenya]]
|22{{0|.00}}
|-
!scope="row"| [[Geothermal energy in Costa Rica|Costa Rica]]
|1{{0|.00}}
|-
!scope="row"| [[Geothermal power in Russia|Russia]]
|308{{0|.00}}
|-
!scope="row"| [[Geothermal power in Turkey|Turkey]]
|2,886{{0|.00}}
|-
!scope="row"| [[Renewable energy in Papua New Guinea|Papua New Guinea]]
|0.10
|-
!scope="row"| Guatemala
|2{{0|.00}}
|-
!scope="row"| [[Geothermal power in Portugal|Portugal]]
|35{{0|.00}}
|-
!scope="row"| [[Geothermal power in China|China]]
|17,870{{0|.00}}
|-
!scope="row"| [[Renewable energy in France|France]]
|2,346{{0|.00}}
|-
!scope="row"| [[Geothermal power in Ethiopia|Ethiopia]]
|2{{0|.00}}
|-
!scope="row"| [[Geothermal power in Germany|Germany]]
|2,848{{0|.00}}
|-
!scope="row"| [[Renewable energy in Austria#Geothermal power|Austria]]
|903{{0|.00}}
|-
!scope="row"| [[Geothermal power in Australia|Australia]]
|16{{0|.00}}
|-
!scope="row"| [[Renewable energy in Thailand|Thailand]]
|128{{0|.00}}
|}

{| class="sortable wikitable" style="text-align:right;"
|+ Installed geothermal electric capacity
!scope="col"| Country
!scope="col"| Capacity (MW) <br />(2024)<ref name="IRENA">{{Cite web |date=25 March 2025 |title=Renewable Energy Capacity Statistics 2025 |url=https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2025/Mar/IRENA_DAT_RE_Capacity_Statistics_2025.pdf |access-date=26 April 2025 |website=[[International Renewable Energy Agency|IRENA]] |page=45 (57 of PDF)}}</ref>
!scope="col"| % of national <br /> electricity <br />production
(2024){{refn|name=calc|Caclulated from<ref name="IRENA"/>}}
!scope="col"| % of global<br />geothermal <br />production (2024){{refn|name=calc}}
|-
!scope="row"| [[Geothermal power in Australia|Australia]]
| 0||0.0%|| 0.0%
|-
!scope="row"| [[Renewable energy in Austria#Geothermal power|Austria]]
| 0||0.0%|| 0.0%
|-
!scope="row"| [[Geothermal power in Canada|Canada]]
| 6||0.0% ||0.0%
|-
!scope="row"| [[Geothermal power in Chile|Chile]]
| 95|| 0.4%|| 0.6%
|-
!scope="row"| [[Geothermal power in China|China]]
| 26||0.0% || 0.2%
|-
!scope="row"| [[Geothermal energy in Taiwan|Taiwan]]
| 7||0.0% || 0.0%
|-
!scope="row"| [[Renewable energy in Costa Rica#Geothermal power|Costa Rica]]
| 263||8.3%|| 1.7%
|-
!scope="row"| [[Energy in Croatia#Geothermal energy|Croatia]]
| 10||0.0%|| 0.0%
|-
!scope="row"| [[Geothermal power in El Salvador|El Salvador]]
| 209||11.2% || 1.4%
|-
!scope="row"| [[Energy in Ethiopia#Geothermal energy|Ethiopia]]
| 7||0.1%|| 0.0%
|-
!scope="row"| [[Renewable energy in France|France]]
| 16||0.0% || 0.1%
|-
!scope="row"| [[Geothermal power in Germany|Germany]]
| 44|| 0.0%||0.3%
|-
!scope="row"| [[Guadeloupe#Energy|Guadeloupe]]
| 15||6.6% || 0.1%
|-
!scope="row"| Guatemala
| 49||1.8% ||0.3%
|-
!scope="row"| [[Renewable energy in Honduras#Geothermal|Honduras]]
| 39|| 2.0%|| 0.3%
|-
!scope="row"| [[Renewable energy in Hungary#Geothermal power|Hungary]]
| 3 || 0.0%|| 0.0%
|-
!scope="row"| [[Geothermal power in Iceland|Iceland]]
| 788|| 26.8%|| 5.1%
|-
!scope="row"| [[Geothermal power in Indonesia|Indonesia]]
| 2,688 || 18.8%|| 17.4%
|-
!scope="row"| [[Geothermal power in Italy|Italy]]
| 772|| 1.1%||5.0%
|-
!scope="row"| [[Geothermal power in Japan|Japan]]
| 461|| 0.3%|| 3.0%
|-
!scope="row"| [[Geothermal power in Kenya|Kenya]]
| 940|| 33.7%|| 6.1%
|-
!scope="row"| [[Energy in Mexico#Geothermal power|Mexico]]
| 999|| 2.9%||6.5%
|-
!scope="row"| [[Geothermal power in New Zealand|New Zealand]]
| 1,275 || 14.3%|| 8.3%
|-
!scope="row"| [[Electricity sector in Nicaragua#Geothermal|Nicaragua]]
| 165|| 21.5%|| 1.1%
|-
! scope="row" | [[Renewable energy in Papua New Guinea|Papua New Guinea]]
| 51 || 12.8%||0.3%
|-
! scope="row" | [[Geothermal power in the Philippines|Philippines]]
| 1,952 || 21.0%||12.7%
|-
! scope="row" | [[Geothermal power in Portugal|Portugal]]
| 29 || 0.1%||0.2%
|- class="sortbottom"
! scope="row" | [[Geothermal power in Romania|Romania]]
| 0 || 0.0%||0.0%
|-
![[Geothermal power in Russia|Russia]]
|81
|0.1%
|0.5%
|-
![[Renewable energy in Thailand|Thailand]]
|0
|0.0%
|0.0%
|-
![[Geothermal energy in Turkey|Turkey]]
|1,734
|2.5%
|11.2%
|-
![[Geothermal energy in the United States|United States]]
|2,703
|0.6%
|17.5%
|-
!'''Total'''
|16,738
|
|
|}

==Geothermal heating==
{{Main|Geothermal heating}}
Geothermal heating is the use of geothermal energy to heat buildings and water for human use. Humans have done this since the Paleolithic era. Approximately seventy countries made direct use of a total of 270 [[petajoule|PJ]] of geothermal heating in 2004. As of 2007, 28 [[gigawatt|GW]] of geothermal heating satisfied 0.07% of global primary energy consumption.<ref name="IPCC" /> [[Thermal efficiency]] is high since no energy conversion is needed, but [[capacity factor]]s tend to be low (around 20%) since the heat is mostly needed in the winter.

Even cold ground contains heat: below {{convert|6|m}} the undisturbed ground temperature is consistently at the Mean Annual Air Temperature<ref>{{Cite web|url=https://www.icax.co.uk/Mean_Annual_Air_Temperature.html|title=Mean Annual Air Temperature &#124; MATT &#124; Ground temperature &#124; Renewable Energy &#124; Interseasonal Heat Transfer &#124; Solar Thermal Collectors &#124; Ground Source Heat Pumps &#124; Renewable Cooling|website=www.icax.co.uk}}</ref> that may be extracted with a [[ground source heat pump]].

==Types==

=== Hydrothermal systems ===
Hydrothermal systems produce geothermal energy by accessing naturally occurring hydrothermal reservoirs. Hydrothermal systems come in either ''vapor-dominated'' or ''liquid-dominated'' forms.

==== Vapor-dominated plants ====
Larderello and The Geysers are vapor-dominated. Vapor-dominated sites offer temperatures from 240 to 300&nbsp;°C that produce superheated steam.

==== Liquid-dominated plants ====
Liquid-dominated reservoirs (LDRs) are more common with temperatures greater than {{convert|200|C}} and are found near volcanoes in/around the Pacific Ocean and in rift zones and hot spots. Flash plants are the common way to generate electricity from these sources. Steam from the well is sufficient to power the plant. Most wells generate 2–10 MW of electricity. Steam is separated from liquid via cyclone separators and drives electric generators. Condensed liquid returns down the well for reheating/reuse. As of 2013, the largest liquid system was [[Cerro Prieto]] in Mexico, which generates 750 MW of electricity from temperatures reaching {{convert|350|C|F}}.

Lower-temperature LDRs (120–200&nbsp;°C) require pumping. They are common in extensional terrains, where heating takes place via deep circulation along faults, such as in the Western US and Turkey. Water passes through a [[heat exchanger]] in a [[Rankine cycle]] binary plant. The water vaporizes an organic working fluid that drives a [[turbine]]. These binary plants originated in the Soviet Union in the late 1960s and predominate in new plants. Binary plants have no emissions.<ref name=sci2013/><ref name=eere>{{cite web|url=http://www1.eere.energy.gov/geothermal/low_temperature_resources.html
|title= Low-Temperature and Co-produced Geothermal Resources |publisher=US Department of Energy}}</ref>

=== Engineered geothermal systems ===
An engineered geothermal system is a geothermal system that engineers have artificially created or improved. Engineered geothermal systems are used in a variety of geothermal reservoirs that have hot rocks but insufficient natural reservoir quality, for example, insufficient geofluid quantity or insufficient rock permeability or porosity, to operate as natural hydrothermal systems. Types of engineered geothermal systems include ''enhanced geothermal systems'', ''closed-loop or advanced geothermal systems'', and some ''superhot rock geothermal systems''.<ref name="auto">{{Cite web |title=Superhot Rock Energy Glossary |url=https://www.catf.us/superhot-rock/glossary/ |access-date=2023-11-29 |website=Clean Air Task Force |language=en}}</ref>

==== Enhanced geothermal systems ====
{{Main|Enhanced geothermal system}}
Enhanced geothermal systems (EGS) actively inject water into wells to be heated and pumped back out. The water is injected under high pressure to expand existing rock fissures to enable the water to flow freely. The technique was adapted from oil and gas [[fracking]] techniques. The geologic formations are deeper and no toxic chemicals are used, reducing the possibility of environmental damage. Instead [[proppant]]s such as sand or ceramic particles are used to keep the cracks open and producing optimal flow rates.<ref>{{Cite web |date=2023-03-16 |title=When Fracturing for Geothermal, Is Proppant Really Necessary? |url=https://jpt.spe.org/when-fracturing-for-geothermal-is-proppant-really-necessary |access-date=2024-02-11 |website=JPT |language=en}}</ref> Drillers can employ [[directional drilling]] to expand the reservoir size.<ref name=sci2013/>

Small-scale EGS have been installed in the [[Rhine Graben]] at [[Soultz-sous-Forêts]] in France and at [[Landau]] and [[Insheim]] in Germany.<ref name=sci2013/>

==== Closed-loop geothermal systems ====
{{Main|Closed-loop geothermal}}

Closed-loop geothermal systems, sometimes colloquially referred to as Advanced Geothermal Systems (AGS), are engineered geothermal systems containing subsurface working fluid that is heated in the hot rock reservoir without direct contact with rock pores and fractures. Instead, the subsurface working fluid stays inside a closed loop of deeply buried pipes that conduct Earth's heat. The advantages of a deep, closed-loop geothermal circuit include: (1) no need for a geofluid, (2) no need for the hot rock to be permeable or porous, and (3) all the introduced working fluid can be recirculated with zero loss.<ref name="auto" /> [[Eavor Technologies|Eavor<sup>tm</sup>]], a Canadian-based geothermal startup, piloted their closed-loop system in shallow soft rock formations in Alberta, Canada. Situated within a sedimentary basin, the geothermal gradient proved to be insufficient for electrical power generation. However, the system successfully produced approximately 11,000 MWh of thermal energy during its initial two years of operation."<ref name=":5" /><ref>{{Cite web |last=Toews |first=Mathew |date=January 11, 2020 |title=Eavor-Lite Demonstration Project |url=https://albertainnovates.ca/wp-content/uploads/2022/08/2506-G2019000423-Eavor-Final-Public-Report-Jan-2021.pdf}}</ref>

==Economics==
{{update|section|date=November 2020}}
As with wind and solar energy, geothermal power has minimal operating costs; capital costs dominate. Drilling accounts for over half the costs, and not all wells produce exploitable resources. For example, as of 2009 a typical well pair (one for extraction and one for injection) in [[Nevada]] can produce 4.5 [[megawatt]]s (MW) and costs about $10&nbsp;million to drill, with a 20% failure rate, making the average cost of a successful well $50 million.<ref name="econ101">{{Citation
| date =October 2009
| title =Geothermal Economics 101, Economics of a 35 MW Binary Cycle Geothermal Plant
| location =New York
| publisher =Glacier Partners
| url =http://www.glacierpartnerscorp.com/geothermal.php
| access-date =2009-10-17
| archive-url =https://web.archive.org/web/20100501143651/http://www.glacierpartnerscorp.com/geothermal.php
| archive-date =2010-05-01
}}</ref>

[[File: Sonoma Plant at The Geysers 4778.png|thumb|A power plant at The Geysers]]

Drilling geothermal wells is more expensive than drilling oil and gas wells of comparable depth for several reasons: 
* Geothermal reservoirs are usually in igneous or metamorphic rock, which is harder to penetrate than the sedimentary rock of typical hydrocarbon reservoirs.
* The rock is often fractured, which causes vibrations that damage bits and other drilling tools.
* The rock is often abrasive, with high quartz content, and sometimes contains highly corrosive fluids.
* The rock is hot, which limits use of downhole electronics.
* Well casing must be cemented from top to bottom, to resist the casing's tendency to expand and contract with temperature changes. Oil and gas wells are usually cemented only at the bottom.
* Well diameters are considerably larger than typical oil and gas wells.<ref>{{cite web|url=https://www1.eere.energy.gov/geothermal/pdfs/drillinghandbook.pdf |first1=J. T. |last1=Finger |first2=D. A. |last2=Blankenship|title=Handbook of Best Practices for Geothermal Drilling Sandia Report SAND2010-6048|publisher=Sandia National Laboratories |date=December 2010 }}</ref>

As of 2007 plant construction and well drilling cost about €2–5&nbsp;million&nbsp;per&nbsp;MW of electrical capacity, while the [[levelised energy cost|break-even]] price was 0.04–0.10&nbsp;€ per&nbsp;kW·h.<ref name="Bertani" /> Enhanced geothermal systems tend to be on the high side of these ranges, with capital costs above $4&nbsp;million per&nbsp;MW and break-even above $0.054 per&nbsp;kW·h.<ref>
{{Cite journal
 | first1 = Subir K. | last1 = Sanyal
 | first2 = James W. | last2 = Morrow
 | first3 = Steven J. | last3 = Butler
 | first4 = Ann | last4 = Robertson-Tait
 | title = Cost of Electricity from Enhanced Geothermal Systems
 | url = http://pangea.stanford.edu/ERE/pdf/IGAstandard/SGW/2007/sanyal1.pdf
 | journal = Proceedings, Thirty-Second Workshop on Geothermal Reservoir Engineering
 | date = January 22–24, 2007
 | place = Stanford, California}}
</ref>

Between 2013 and 2020, private investments were the main source of funding for [[renewable energy]], comprising approximately 75% of total financing. The mix between private and public funding varies among different renewable energy technologies, influenced by their market appeal and readiness. In 2020, geothermal energy received just 32% of its investment from private sources.<ref>{{Cite web |date=2023-02-22 |title=Global landscape of renewable energy finance 2023 |url=https://www.irena.org/Publications/2023/Feb/Global-landscape-of-renewable-energy-finance-2023 |access-date=2024-03-21 |website=www.irena.org |language=en}}</ref><ref>{{Cite web |date=February 2023 |title=Global landscape of renewable energy finance 2023 |url=https://mc-cd8320d4-36a1-40ac-83cc-3389-cdn-endpoint.azureedge.net/-/media/Files/IRENA/Agency/Publication/2023/Feb/IRENA_CPI_Global_RE_finance_2023.pdf?rev=8668440314f34e588647d3994d94a785 |website=International Renewable Energy Agency (IRENA) |access-date=2024-03-21 |archive-date=2024-03-21 |archive-url=https://web.archive.org/web/20240321092402/https://mc-cd8320d4-36a1-40ac-83cc-3389-cdn-endpoint.azureedge.net/-/media/Files/IRENA/Agency/Publication/2023/Feb/IRENA_CPI_Global_RE_finance_2023.pdf?rev=8668440314f34e588647d3994d94a785 }}</ref>

=== Socioeconomic benefits ===
In January 2024, the [[Energy Sector Management Assistance Program]] (ESMAP) report "Socioeconomic Impacts of Geothermal Energy Development" was published, highlighting the substantial [[Socioeconomics|socioeconomic]] benefits of geothermal energy development, which notably exceeds those of wind and solar by generating an estimated 34 jobs per megawatt across various sectors. The report details how geothermal projects contribute to skill development through practical on-the-job training and formal education, thereby strengthening the local workforce and expanding employment opportunities. It also underscores the collaborative nature of geothermal development with [[Local community|local communities]], which leads to improved infrastructure, skill-building programs, and revenue-sharing models, thereby enhancing access to reliable electricity and heat. These improvements have the potential to boost [[agricultural productivity]] and [[food security]]. The report further addresses the commitment to advancing gender equality and social inclusion by offering job opportunities, education, and training to underrepresented groups, ensuring fair access to the benefits of geothermal development. Collectively, these efforts are instrumental in driving domestic economic growth, increasing fiscal revenues, and contributing to more stable and diverse national economies, while also offering significant social benefits such as better health, education, and community cohesion.<ref>{{Cite web |author=((Energy Sector Management Assistance Program (ESMAP))) |date=2024-01-19 |title=Publication: Geothermal Energy: Unveiling the Socioeconomic Benefit |url=https://openknowledge.worldbank.org/entities/publication/d63d3c50-2bd0-46d7-a94d-999c6b0f359e |publisher=The World Bank Open Knowledge Repository |access-date=2024-04-06}}</ref>

== Development ==
Geothermal projects have several stages of development. Each phase has associated risks. Many projects are canceled during the stages of reconnaissance and geophysical surveys, which are unsuitable for traditional lending. At later stages can often be equity-financed.<ref>{{cite journal
|last=Deloitte|first=Department of Energy|title=Geothermal Risk Mitigation Strategies Report|journal=Office of Energy Efficiency and Renewable Energy Geothermal Program|date=February 15, 2008}}</ref>

=== Precipitate scaling ===

A common issue encountered in geothermal systems arises when the system is situated in carbonate-rich formations. In such cases, the fluids extracting heat from the subsurface often dissolve fragments of the rock during their ascent towards the surface, where they subsequently cool. As the fluids cool, dissolved cations precipitate out of solution, leading to the formation of calcium scale, a phenomenon known as calcite scaling. This calcite scaling has the potential to decrease flow rates and necessitate system downtime for maintenance purposes.<ref>{{Cite journal |last1=Bu |first1=Xianbiao |last2=Jiang |first2=Kunqing |last3=Wang |first3=Xianlong |last4=Liu |first4=Xiao |last5=Tan |first5=Xianfeng |last6=Kong |first6=Yanlong |last7=Wang |first7=Lingbao |date=2022-09-01 |title=Analysis of calcium carbonate scaling and antiscaling field experiment |url=https://www.sciencedirect.com/science/article/pii/S0375650522000840 |journal=Geothermics |volume=104 |article-number=102433 |doi=10.1016/j.geothermics.2022.102433 |issn=0375-6505|url-access=subscription }}</ref>

==Sustainability==
Geothermal energy is considered to be sustainable because the heat extracted is so small compared to the Earth's heat content, which is approximately 100 billion times 2010 worldwide annual energy consumption.<ref name="IPCC" /> Earth's heat flows are not in equilibrium; the planet is cooling on geologic timescales. Anthropic heat extraction typically does not accelerate the cooling process.

Wells can further be considered renewable because they return the extracted water to the borehole for reheating and re-extraction, albeit at a lower temperature.

Replacing material use with energy has reduced the human environmental footprint in many applications. Geothermal has the potential to allow further reductions. For example, [[Iceland]] has sufficient geothermal energy to eliminate fossil fuels for electricity production and to heat [[Reykjavík|Reykjavik]] sidewalks and eliminate the need for gritting.<ref>{{Cite web |last=Berg |first=Georg |date=2022-05-10 |title=Under Cover |url=https://tellerrandstories.de/moment-mal/island-under-cover/ |access-date=2022-07-23 |website=Tellerrand-Stories |language=de}}</ref>

[[File:Geothermal.Electricity.NZ.Poihipi.png|thumb|upright=1.5|Electricity generation at Poihipi, New Zealand]]
[[File:Geothermal.Electricity.NZ.Ohaaki.png|thumb|upright=1.5|Electricity generation at Ohaaki, New Zealand]]
[[File:Geothermal.Electricity.NZ.Wairakei.png|thumb|upright=1.5|Electricity generation at Wairakei, New Zealand]]

However, local effects of heat extraction must be considered.<ref name="sustainability" /> Over the course of decades, individual wells draw down local temperatures and water levels. The three oldest sites, at Larderello, [[Wairakei]], and the Geysers experienced reduced output because of local depletion. Heat and water, in uncertain proportions, were extracted faster than they were replenished. Reducing production and injecting additional water could allow these wells to recover their original capacity. Such strategies have been implemented at some sites. These sites continue to provide significant energy.<ref name="Wairakei">{{Citation
| last =Thain
| first =Ian A.
| date =September 1998
| title =A Brief History of the Wairakei Geothermal Power Project
| periodical =Geo-Heat Centre Quarterly Bulletin
| location =Klamath Falls, Oregon
| publisher =Oregon Institute of Technology
| volume =19
| issue =3
| pages =1–4
| url =http://geoheat.oit.edu/bulletin/bull19-3/art1.pdf
| access-date =2009-06-02
| archive-date =2011-06-14
| archive-url =https://web.archive.org/web/20110614115823/http://geoheat.oit.edu/bulletin/bull19-3/art1.pdf
}}</ref><ref name="300years">
{{Citation
| last1 =Axelsson | first1 =Gudni
| last2 =Stefánsson | first2 =Valgardur
| last3 =Björnsson | first3 =Grímur
| last4 = Liu | first4 =Jiurong
| date =April 2005
| title =Sustainable Management of Geothermal Resources and Utilization for 100 – 300 Years
| periodical =Proceedings World Geothermal Congress 2005
| publisher =International Geothermal Association
| url =http://www.geothermal-energy.org/pdf/IGAstandard/WGC/2005/0507.pdf
| access-date =2010-01-17
}}</ref>

The [[Wairakei Power Station|Wairakei]] power station was commissioned in November 1958, and it attained its peak generation of 173 [[Watt#Megawatt|MW]] in 1965, but already the supply of high-pressure steam was faltering. In 1982 it was down-rated to intermediate pressure and the output to 157 MW. In 2005 two 8 MW [[isopentane]] systems were added, boosting output by about 14 MW. Detailed data were lost due to re-organisations.

==Environmental effects==
[[File:Puhagan geothermal plant.jpg|thumb|Geothermal power station in the Philippines]]
[[File:Krafla Geothermal Station.jpg|thumb|Krafla Geothermal Station in northeast Iceland]]

Fluids drawn from underground carry a mixture of gasses, notably [[carbon dioxide]] ({{chem|CO|2|}}), [[hydrogen sulfide]] ({{chem|H|2|S|}}), [[methane]] ({{chem|CH|4|}}) and [[ammonia]] ({{chem|NH|3|}}). These pollutants contribute to [[global warming]], [[acid rain]] and noxious smells if released. Existing geothermal electric plants emit an average of {{convert|122|kg|lb}} of {{chem|CO|2|}} per megawatt-hour (MW·h) of electricity, a small fraction of the [[emission intensity]] of fossil fuel plants.<ref name="CO2">
{{Citation
| last1 = Bertani | first1 = Ruggero
| last2 = Thain | first2 = Ian
| title = Geothermal Power Generating Plant CO<sub>2</sub> Emission Survey
| journal = IGA News
| issue = 49
| pages = 1–3
| date = July 2002
| url = http://www.geothermal-energy.org/files-39.html
| archive-url = https://web.archive.org/web/20110726100945/http://www.geothermal-energy.org/files-39.html
| archive-date = 2011-07-26
| access-date = 2010-01-17
}}</ref>{{Update inline|date=October 2020|reason=Lots of new geothermal since 2002}} A few plants emit more pollutants than gas-fired power, at least in the first few years, such as some [[geothermal power in Turkey]].<ref>{{Citation|last1=Tut Haklidir|first1=Fusun S.|title=Global CO2 Capture and Storage Methods and a New Approach to Reduce the Emissions of Geothermal Power Plants with High CO2 Emissions: A Case Study from Turkey|date=2019|work=Climate Change and Energy Dynamics in the Middle East: Modeling and Simulation-Based Solutions|pages=323–357|editor-last=Qudrat-Ullah|editor-first=Hassan|series=Understanding Complex Systems|publisher=Springer International Publishing|doi=10.1007/978-3-030-11202-8_12|isbn=978-3-030-11202-8|last2=Baytar|first2=Kaan|last3=Kekevi|first3=Mert|s2cid=133813028 |editor2-last=Kayal|editor2-first=Aymen A.|quote=CO2 emissions emitted by the geothermal power plants range from 900 to 1300 gr/kwh}}</ref> Plants that experience high levels of acids and volatile chemicals are typically equipped with emission-control systems to reduce the exhaust. New emerging closed looped technologies developed by Eavor have the potential to reduce these emissions to zero.<ref name=":5">{{Cite web |date=2019-04-24 |title=Eavor-Loop Demonstration Project |url=https://natural-resources.canada.ca/science-and-data/funding-partnerships/funding-opportunities/current-investments/eavor-loop-demonstration-project/21896 |access-date=2024-02-10 |website=Natural Resources Canada}}</ref>

Water from geothermal sources may hold in solution trace amounts of toxic elements such as [[Mercury (element)|mercury]], [[arsenic]], [[boron]], and [[antimony]].<ref name="toxic">{{Citation | last1 = Bargagli | first1 = R. | last2 = Catenil | first2 = D. | last3 = Nellil | first3 = L. | last4 = Olmastronil | first4 = S. | last5 = Zagarese | first5 = B. | s2cid = 30238608 | title = Environmental Impact of Trace Element Emissions from Geothermal Power Plants | journal = Environmental Contamination Toxicology | volume = 33 | issue = 2 | pages = 172–181 | year =1997 | doi = 10.1007/s002449900239| pmid = 9294245 }}</ref>  These chemicals precipitate as the water cools, and can damage surroundings if released. The modern practice of returning geothermal fluids into the Earth to stimulate production has the side benefit of reducing this environmental impact.

Construction can adversely affect land stability. [[Subsidence]] occurred in the Wairakei field.<ref name="utilization" /> In [[Staufen im Breisgau]], Germany, [[tectonic uplift]] occurred instead. A previously isolated [[anhydrite]] layer came in contact with water and turned it into gypsum, doubling its volume.<ref>{{cite web|url=http://www1.eere.energy.gov/geothermal/low_temperature_resources.html |title=Staufen: Risse: Hoffnung in Staufen: Quellvorgänge lassen nach |publisher=badische-zeitung.de |access-date=2013-04-24}}</ref><ref>{{Cite web |title=Relaunch explanation |url=https://www.dlr.de/EN/Service/about-relaunch/explanation.html |access-date=2022-08-05 |website=NAV_NODE DLR Portal |language=en |archive-date=2020-05-08 |archive-url=https://web.archive.org/web/20200508000704/https://www.dlr.de/EN/Service/about-relaunch/explanation.html }}</ref><ref>{{Cite web |title=WECHSELWIRKUNG - Numerische Geotechnik |url=http://www.wechselwirkung.eu/en/reference_stau.php |access-date=2022-08-05 |website=www.wechselwirkung.eu}}</ref> [[Enhanced geothermal systems]] can trigger [[earthquake]]s as part of [[hydraulic fracturing]]. A project in [[Basel]], [[Switzerland]] was suspended because more than 10,000 seismic events measuring up to 3.4 on the [[Richter Scale]] occurred over the first 6 days of water injection.<ref>
{{Citation| first1 = N.| last1 = Deichmann| title = Seismicity Induced by Water Injection for Geothermal Reservoir Stimulation 5&nbsp;km Below the City of Basel, Switzerland| year = 2007| bibcode = 2007AGUFM.V53F..08D| last2 = Mai| last3 = Bethmann
| last4 = Ernst| last5 = Evans| last6 = Fäh| last7 = Giardini| last8 = Häring| last9 = Husen| volume = 53| pages = V53F–08 | journal = American Geophysical Union|display-authors=etal}}</ref>

Geothermal power production has minimal land and freshwater requirements. Geothermal plants use {{convert|3.5|km2}} per&nbsp;gigawatt of electrical production (not capacity) versus {{convert|32|km2}} and {{convert|12|km2}} for [[coal]] facilities and [[wind farm]]s respectively.<ref name="utilization" /> They use {{convert|20|L|usgal}} of freshwater per MW·h versus over {{convert|1000|L|usgal}} per&nbsp;MW·h for nuclear, coal, or oil.<ref name="utilization" />

==Production==
{{Globalize|section|date=November 2020}}

===Philippines===

The [[Philippines]] began geothermal research in 1962 when the [[Philippine Institute of Volcanology and Seismology]] inspected the geothermal region in [[Tiwi, Albay]].<ref name=":2">{{Cite journal |last1=Sussman |first1=David |last2=Javellana |first2=Samson P. |last3=Benavidez |first3=Pio J. |date=1993-10-01 |title=Geothermal energy development in the Philippines: An overview |journal=Geothermics |series=Special Issue Geothermal Systems of the Philippines |language=en |volume=22 |issue=5 |pages=353–367 |doi=10.1016/0375-6505(93)90024-H |bibcode=1993Geoth..22..353S |issn=0375-6505}}</ref> The first geothermal power plant in the Philippines was built in 1977, located in Tongonan, [[Leyte]].<ref name=":2" /> The [[New Zealand Government|New Zealand government]] contracted with the Philippines to build the plant in 1972.<ref name=":3">{{Citation |last1=Ratio |first1=Marnel Arnold |title=The Philippine Experience in Geothermal Energy Development |date=2019 |work=Geothermal Energy and Society |pages=217–238 |editor-last=Manzella |editor-first=Adele |place=Cham |publisher=Springer International Publishing |language=en |doi=10.1007/978-3-319-78286-7_14 |isbn=978-3-319-78286-7 |s2cid=134654953 |last2=Gabo-Ratio |first2=Jillian Aira |last3=Tabios-Hillebrecht |first3=Anna Leah |series=Lecture Notes in Energy |volume=67 |editor2-last=Allansdottir |editor2-first=Agnes |editor3-last=Pellizzone |editor3-first=Anna}}</ref> The Tongonan Geothermal Field (TGF) added the Upper Mahiao, Matlibog, and South Sambaloran plants, which resulted in a 508 MV capacity.<ref name=":4">{{Cite web |last1=Dacillo |first1=Danilo B. |last2=Colo |first2=Marie Hazel B. |last3=Andrino |first3=Romeo P. Jr. |last4=Alcober |first4=Edwin H. |last5=Sta. Ana |first5=Francis Xavier |last6=Malate |first6=Ramonchito Cedric M. |date=April 25–29, 2010 |title=Tongonan Geothermal Field: Conquering the Challenges of 25 Years of Production |url=https://www.geothermal-energy.org/pdf/IGAstandard/WGC/2010/0506.pdf}}</ref>

The first geothermal power plant in the Tiwi region opened in 1979, while two other plants followed in 1980 and 1982.<ref name=":2" /> The Tiwi geothermal field is located about 450&nbsp;km from [[Manila]].<ref>{{Cite web |last1=Fronda |first1=Ariel D. |last2=Marasigan |first2=Mario C. |last3=Lazaro |first3=Vanessa S. |date=April 19–25, 2015 |title=Geothermal Development in the Philippines: The Country Update |url=http://large.stanford.edu/courses/2016/ph240/makalinao1/docs/01053.pdf}}</ref> The three geothermal power plants in the Tiwi region produce 330 MWe, putting the Philippines behind the [[United States]] and [[Mexico]] in geothermal growth.<ref>{{Cite web |last=Alcaraz |first=A.P. |title=Geothermal Energy Development - A Boon to Philippine Energy Self-Reliance Efforts |url=http://large.stanford.edu/courses/2016/ph240/makalinao1/docs/alcaraz.pdf |access-date=May 29, 2022}}</ref> The Philippines has 7 geothermal fields and continues to exploit geothermal energy by creating the Philippine Energy Plan 2012–2030 that aims to produce 70% of the country's energy by 2030.<ref>{{Cite web |last=Cusi |first=Alfonso G. |title=Philippine Energy Plan 2012–2030 Update |url=https://policy.asiapacificenergy.org/sites/default/files/Philippine%20Energy%20Plan%202016-2030.pdf |access-date=May 29, 2022}}</ref><ref>{{Cite web |last=Hanson |first=Patrick |date=2019-07-12 |title=Geothermal Country Overview: Philippines |url=https://www.geoenergymarketing.com/energy-blog/geothermal-country-overview-philippines/ |access-date=2022-05-29 |website=GeoEnergy Marketing |language=en-US}}</ref>

===United States===

According to the Geothermal Energy Association (GEA) installed geothermal capacity in the United States grew by 5%, or 147.05 MW, in 2013. This increase came from seven geothermal projects that began production in 2012. GEA revised its 2011 estimate of installed capacity upward by 128 MW, bringing installed US geothermal capacity to 3,386 MW.<ref>{{Citation|url=http://geo-energy.org/pressReleases/2013/GEA2013UpdateRelease.aspx |title=GEA Update Release 2013 |publisher=Geo-energy.org |date=2013-02-26 |access-date=2013-10-09}}</ref>

===Hungary===

The municipal government of [[Szeged]] is trying to cut down its gas consumption by 50 percent by utilizing geothermal energy for its district heating system. The Szeged geothermal power station has 27 wells, 16 heating plants, and 250 kilometres of distribution pipes.<ref>{{Cite web|url=https://www.hungarianconservative.com/articles/reviews/szeged_geothermal_energy_euronews/|title=Szeged's Unique Use of Geothermal Energy|website=HungarianConservative.com}}</ref>

==See also==
{{Portal|Renewable energy}}
*[[2010 World Geothermal Congress]]
*[[Deep water source cooling]]
*[[Earth's internal heat budget]]
*[[Geothermal activity]]
*[[Hydrothermal vent]]
*[[International Geothermal Association]]
*[[Ocean thermal energy conversion]]
*[[Relative cost of electricity generated by different sources]]
*[[List of renewable energy topics by country and territory]]
*[[List of mining journals]]
*[[New drilling technologies]] – [[Plasma deep drilling technology]], [[Spallation|hydrothermal spallation]], [[hydraulic mining]], [[laser drilling]], [[Gyrotron]].
*[[Quaise]] — company that does a [[millimeter-wave]] drilling system for converting existing power stations to use superdeep geothermal energy
*[[Thermal battery]]

==References==
{{Reflist}}

==External links==
{{Wiktionary|geothermal}}
{{Commons category|Geothermal energy}}
* {{cite web |title=The Future of Geothermal Energy |url=https://iea.blob.core.windows.net/assets/b5b73936-ee21-4e38-843b-8ba7430fbe92/TheFutureofGeothermal.pdf |publisher=International Energy Agency (IEA) |archive-url=https://web.archive.org/web/20241214043554/https://iea.blob.core.windows.net/assets/b5b73936-ee21-4e38-843b-8ba7430fbe92/TheFutureofGeothermal.pdf |archive-date=14 December 2024 |date=December 2024 |url-status=live}}
* {{Cite web |date=2023-07-16 |url=https://www.higp.hawaii.edu/hggrc/ |access-date=2023-08-07 |title=Hawaiʻi Groundwater & Geothermal Resources Center |language=en-US|website=University of Hawaii at Manoa}}
* {{Cite web |title= Geothermal Rising :: Using the Earth to Save the Earth |url=https://www.geothermal.org/ |access-date=2023-08-07 |website=www.geothermal.org}}
* [https://www.energy.gov/eere/geothermal/geothermal-technologies-office Energy Efficiency and Renewable Energy – Geothermal Technologies Office]
* [http://www.iea-gia.org/ International Energy Agency Geothermal Energy Homepage]
* [https://www.nrel.gov/geothermal/ NREL – Geothermal Research]
* [https://www.youtube.com/watch?v=4jzXonyL6PM 2022 discussion of geothermal energy advantages and challenges]

{{Geothermal power|state=expanded}}
{{Electricity generation}}
{{Natural resources}}

{{Authority control}}

[[Category:Geothermal energy| ]]
[[Category:Power station technology]]
[[Category:Sustainable energy]]
[[Category:Volcanism]]