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{{Short description|Privately owned British energy company}}
{{Use dmy dates|date=October 2019}}
{{Use dmy dates|date=October 2019}}
'''United Downs Deep Geothermal Power''' is the United Kingdom's first [[Geothermal power|geothermal electricity]] project. It is situated near [[Redruth]] in [[Cornwall]], England. It is owned and operated by Geothermal Engineering (GEL), a private UK company. The drilling site is on the [[United Downs]] industrial estate, chosen for its geology, existing grid connection, proximity to access roads and limited impact on local communities.<ref name=":1">{{Cite journal |last=Farndale, H., Law, R. and Beynon, S. |date=2022 |title=An Update on the United Downs Geothermal Power Project, Cornwall, UK |journal=European Geothermal Congress, Berlin, Germany {{!}} 17–21 October 2022}}</ref> Energy is extracted by cycling water through a naturally hot reservoir and using the heated water to drive a turbine to produce electricity and for direct heating. The company plans to begin delivering electricity (2{{nbsp}}MWe) and heat (<10{{nbsp}}MWth) in 2024. A [[lithium]] resource was discovered in the well.<ref name=":5">{{Cite web |last=Cariaga |first=Carlo |date=2023-03-08 |title=GEL receives £15 million funding for deep geothermal in UK |url=https://www.thinkgeoenergy.com/gel-receives-15-million-funding-for-deep-geothermal-in-uk/ |access-date=2023-08-08 |website=Think Geoenergy |language=en-US}}</ref>
'''United Downs Deep Geothermal Power''' is a planned [[geothermal energy]] power plant in [[Redruth]] in [[Cornwall]], England. It aims to begin live operation by 2020.

[[Image:geothermal capacity.svg|thumb|right|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
| publication-place =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">
{{Citation|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 |conference=IPCC Scoping Meeting on Renewable Energy Sources |editor=O. Hohmeyer and T. Trittin |location=Luebeck, Germany |pages=59–80 |url=http://www.iea-gia.org/documents/FridleifssonetalIPCCGeothermalpaper2008FinalRybach20May08_000.pdf |access-date=2009-04-06 |url-status=dead |archive-url=https://web.archive.org/web/20100308014920/http://www.iea-gia.org/documents/FridleifssonetalIPCCGeothermalpaper2008FinalRybach20May08_000.pdf |archive-date=March 8, 2010 }}</ref>
]]

Sited on the United Downs industrial estate, the plant will generate 10&nbsp;MW of [[electricity]] to be sold to the [[National Grid (UK)|National Grid]]; and 55&nbsp;MW of [[thermal energy]], to be distributed locally. It is being developed by Geothermal Engineering Limited, a privately owned [[Great Britain|British]] company founded in 2008 specialising in the development of [[geothermal]] resources.

The [[Enhanced Geothermal System]] being employed to generate power at United Downs targets volumes of rock that already exhibit enhanced permeability. The plan for United Downs is to drill three boreholes to a true depth of {{convert|4.5|km}}. Water is pumped down a borehole which then travels through fractures in the rock, capturing the heat, until it is pumped out of one or more production boreholes as very hot pressurised water, which is then converted into electricity using a steam turbine.<ref>{{Cite news
| title=We're mining for heat in Cornwall
⚫
| newspaper=[[The Independent]]
⚫
| date=11 October 2009
| url=https://www.independent.co.uk/news/business/news/were-mining-for-heat-in-cornwall-1800793.html
| access-date= 30 January 2010
| location=London
| first=Mark
| last=Halper}}
⚫
</ref><ref>{{Cite news
| title= Geothermal power plant set to become a reality in Cornwall
| work=New Civil Engineer
| publisher=Emap Ltd.
| date= 19 October 2009
| url=http://www.nce.co.uk/news/geotechnical/geothermal-power-plant-set-to-become-a-reality-in-cornwall/5209692.article
| access-date= 30 January 2010}}
</ref> The water for charging the reservoir will come from flooded mines, not from the local water supply. The hot water produced by the plant can also be used to supply thermal energy and [[air conditioning]] (via an [[absorption chiller]]) to the surrounding area.


==History==
==History==
The [[Camborne School of Mines]] led Cornish [[Hot dry rock geothermal energy|Hot Dry Rocks]] (HDR) project, undertaken in the 1980s at [[Rosemanowes Quarry]], was designed to test the theory of inducing a fracture network within granite to create a geothermal reservoir.<ref name=":0">{{Cite journal |last=Farndale, H. and Law, R. |date=2022 |title=An Update on the United Downs Geothermal Power Project, Cornwall, UK |url=https://pangea.stanford.edu/ERE/db/GeoConf/papers/SGW/2022/Farndale.pdf |journal=PROCEEDINGS, 47th Workshop on Geothermal Reservoir Engineering, Stanford University, Stanford, California, February 7–9, 2022}}</ref><ref name=":1" />
Geothermal Engineering announced the plans for the United Downs geothermal power station in October 2009 and held a local consultation in [[Carharrack]] in the same month.<ref>{{Cite news

| title='Hot rocks' power plant plans revealed
Geothermal Engineering was founded in 2008 to specialise in the development of [[Geothermal power|geothermal]] resources. Project funding was secured over the following five years from the European Regional Development Fund, Cornwall Council and private investors.<ref>{{Cite news
| newspaper=[[Western Morning News]]
| date=13 October 2009
| url=http://www.westernmorningnews.co.uk/Firm-reveals-plans-hot-rocks-power-plant/story-11505838-detail/story.html
| access-date= 15 August 2015}}
</ref> In December 2009 the company received £1.475 million in funding from the [[Department of Energy and Climate Change]].<ref>{{Cite news
| title=Geothermal power plant gets funds
| title=Geothermal power plant gets funds
| publisher=[[BBC News]]
| publisher=[[BBC News]]
Line 50: Line 12:
| url=http://news.bbc.co.uk/1/hi/england/cornwall/8425272.stm
| url=http://news.bbc.co.uk/1/hi/england/cornwall/8425272.stm
| access-date= 30 January 2010}}
| access-date= 30 January 2010}}
</ref>
</ref><ref>{{Cite news
On 13 August 2010 the United Downs plant was granted planning permission by [[Cornwall Council]] in a unanimous vote.<ref>{{Cite news
| title='Hot rocks' geothermal energy plant promises a UK first for Cornwall
| title='Hot rocks' geothermal energy plant promises a UK first for Cornwall
| newspaper=[[Western Morning News]]
| newspaper=[[Western Morning News]]
Line 59: Line 19:
| access-date= 15 August 2015}}
| access-date= 15 August 2015}}
</ref><ref>{{Cite news
</ref><ref>{{Cite news
⚫
| title=UK's first geothermal plant given go-ahead
| newspaper=[[Financial Times]]
| date=15 October 2010
⚫
| url=http://www.ft.com/cms/s/0/ecc4b012-a898-11df-86dd-00144feabdc0.html
| access-date= 17 August 2010}}
</ref> At that time, the drilling of the first well was expected to begin in early 2011 and the plant was expected to be operational by 2013-2014.<ref>{{Cite news
| title=Drilling to begin for Cornwall geothermal power plant in 2011
| title=Drilling to begin for Cornwall geothermal power plant in 2011
| newspaper=[[The Guardian]]
| newspaper=[[The Guardian]]
Line 76: Line 30:
| url=http://www.theecologist.org/News/news_round_up/385372/geothermal_projects_get_funding_boost.html
| url=http://www.theecologist.org/News/news_round_up/385372/geothermal_projects_get_funding_boost.html
| access-date= 30 January 2010}}
| access-date= 30 January 2010}}
</ref>
</ref><ref>{{Cite news
⚫
| title=UK's first geothermal plant given go-ahead

⚫
| newspaper=[[Financial Times]]
In November 2011, Geothermal Engineering was awarded a grant of £6m from the [[European Regional Development Fund]] towards the cost of the project and drilling of the first well was expected to begin in late 2012.<ref>{{Cite web
⚫
| date=15 October 2010
⚫
| url=http://www.ft.com/cms/s/0/ecc4b012-a898-11df-86dd-00144feabdc0.html
⚫
| access-date= 17 August 2010}}
⚫
</ref><ref>{{Cite web
| url=http://www.investincornwall.com/news/6-million-grant-for-geothermal-energy-project-in-cornwall/
| url=http://www.investincornwall.com/news/6-million-grant-for-geothermal-energy-project-in-cornwall/
| title=£6 Million Grant For Geothermal Energy Project in Cornwall
| title=£6 Million Grant For Geothermal Energy Project in Cornwall
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| publisher=Invest in Cornwall
| publisher=Invest in Cornwall
| access-date=2 September 2013}}
| access-date=2 September 2013}}
</ref>
</ref><ref>{{Cite news

In April 2013, the grant was withdrawn due to the company's failure to attract private funding for the project.<ref>{{Cite news
| title=Geothermal project on rocks after funding blow
| title=Geothermal project on rocks after funding blow
| newspaper=this is Cornwall
| newspaper=this is Cornwall
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</ref>
</ref>


GEL drilled two wells into the Porthtowan fault zone between November 2018 and June 2019. The geothermal production well reached a depth of {{convert|5275|m|abbr=on}} and the fluid injection well {{convert|2393|m|abbr=on}}.<ref name=":0" /><ref name=":1" />
In 2017, United Downs looked at raise £4.4m of private funding via [[debenture]]s offered by [[renewable energy]] debit [[crowdfunding]] specialists [[Abundance Investment]].<ref>{{cite news|last1=Vaughan|first1=Adam|title='Groundbreaking': Cornwall geothermal project seeks funds|url=https://www.theguardian.com/environment/2017/jul/16/groundbreaking-cornwall-geothermal-project-seeks-funds|access-date=1 August 2017|work=[[The Guardian]]|publisher=[[Guardian Media Group]]|date=16 July 2017}}</ref> It reached its target in the first week of August 2017, less than a fortnight after being listed.<!-- It was trailed in article in The Guardian on 16 July 2017, and the listing went live shortly afterwards. It met its target of £4.4m in the few days of August--> Abundance planned to then raise further funds by issuing more debentures of £95,000 or over, with the total raised to be a maximum of £5.27m.<ref>{{cite web|last1=Richter|first1=Alexander|title=UK geothermal project successfully raises $5.7 million in crowdfunding campaign|url=http://www.thinkgeoenergy.com/uk-geothermal-project-successfully-raises-5-7-million-in-crowdfunding-campaign/|website=ThinkGeoEnergy|access-date=16 August 2017}}</ref>

Between August 2020 and July 2021, the wells underwent a series of injection tests to analyse the [[hydrology]] within the fractured geothermal reservoir. In addition, in July 2021, full reservoir testing (simultaneous production and injection) was undertaken for seven days.<ref name=":1" /> During this process, the reservoir was destressed to prevent microseismic events occurring during long term operation.<ref name=":1" /><ref>{{Cite journal |last=Jupe, A., Law, R. and Farndale, H. |date=2022 |title=Implementation of an Induced Seismicity Protocol for the United Downs Deep Geothermal Power Project, United Kingdom |journal=European Geothermal Congress, Berlin, Germany {{!}} 17–21 October 2022}}</ref> GEL adhered to a strict monitoring, management and mitigation procedure to ensure that any induced seismicity was understood by community members.<ref>{{Cite web |title=Seismicity – Geothermal Engineering Ltd |url=http://geothermalengineering.co.uk/seismicity-2/ |access-date=2022-04-29 |language=en-GB}}</ref>

In August 2020, the project's operations were further funded by the [[UK Government|UK]] Getting Building Fund. GEL received a share of £14.3{{nbsp}}million to demonstrate that lithium could be produced from geothermal brines.<ref>{{cite web |date=4 August 2020 |title=LEP agrees £14M investment |url=https://businesscornwall.co.uk/news-by-industry/public-sector-news-categories/2020/08/lep-agrees-14m-investment/ |access-date=17 July 2021 |website=Business Cornwall}}</ref> As of 2021, project costs were approximately £30{{nbsp}}million.

⚫
In January 2021, GEL agreed to sell 3{{nbsp}}MW of power for ten years to [[Ecotricity]].<ref name=":2">{{Cite web |date=2021-01-04 |title=Sold! The UK's first geothermal electricity to the grid {{!}} |url=https://cornishstuff.com/2021/01/04/sold-the-uks-first-geothermal-electricity-to-the-grid/ |access-date=2021-01-07 |language=en-US}}</ref><ref name=":3">{{Cite web |date=2021-01-07 |title=Ecotricity seals 10-year agreement to take geothermal power from Cornish plant |url=https://www.energylivenews.com/2021/01/07/ecotricity-seals-10-year-agreement-to-take-geothermal-power-from-cornish-plant/ |access-date=2021-03-15 |website=Energy Live News |language=en-US}}</ref> In March 2023, the company received another £15{{nbsp}}million in private funding.<ref name=":5" />

== Geology ==
The geothermal system employed to generate power at United Downs targeted a [[Radiogenic nuclide|radiogenic]] [[Cornubian batholith|granite batholith]] that exhibited enhanced [[Permeability (Earth sciences)|permeability]] due to its intersection with the Porthtowan [[Fault Zone|fault zone]].<ref>{{Cite magazine |date=19 October 2009 |title=Geothermal power plant set to become a reality in Cornwall |magazine=New Civil Engineer |publisher=Emap Ltd. |url=http://www.nce.co.uk/news/geotechnical/geothermal-power-plant-set-to-become-a-reality-in-cornwall/5209692.article |access-date=30 January 2010}}
</ref><ref>{{Cite news |last=Halper |first=Mark |date=11 October 2009 |title=We're mining for heat in Cornwall |newspaper=[[The Independent]] |location=London |url=https://www.independent.co.uk/news/business/news/were-mining-for-heat-in-cornwall-1800793.html |access-date=30 January 2010}}
</ref><ref>{{Cite journal |last1=Rezaie |first1=Behnaz |last2=Rosen |first2=Marc A. |date=2012-05-01 |title=District heating and cooling: Review of technology and potential enhancements |url=https://www.sciencedirect.com/science/article/pii/S030626191100242X |journal=Applied Energy |language=en |volume=93 |pages=2–10 |doi=10.1016/j.apenergy.2011.04.020 |issn=0306-2619}}</ref><ref>{{Cite journal |last1=Ozgener |first1=Leyla |last2=Hepbasli |first2=Arif |last3=Dincer |first3=Ibrahim |date=2007-10-01 |title=A key review on performance improvement aspects of geothermal district heating systems and applications |url=https://www.sciencedirect.com/science/article/pii/S1364032106000517 |journal=Renewable and Sustainable Energy Reviews |language=en |volume=11 |issue=8 |pages=1675–1697 |doi=10.1016/j.rser.2006.03.006 |issn=1364-0321}}</ref>

The [[Cornubian batholith|Cornubian granite batholith]] stretches from [[Dartmoor]] to the [[Isles of Scilly]] and contains a high concentration of heat-producing isotopes such as thorium (Th), uranium (U) and potassium (K). This natural heat production means that the [[heat flow]] at United Downs is approximately double the UK average at 120{{nbsp}}mWm<sup>−2</sup>, and [[geothermal gradient]] is around 33-35&nbsp;°C/km, almost 10&nbsp;°C/km hotter than large parts of the UK.<ref name=":1" /><ref>{{Cite journal |last1=Beamish |first1=David |last2=Busby |first2=Jon |date=2016-03-24 |title=The Cornubian geothermal province: heat production and flow in SW England: estimates from boreholes and airborne gamma-ray measurements |journal=Geothermal Energy |volume=4 |issue=1 |pages=4 |doi=10.1186/s40517-016-0046-8 |s2cid=55659348 |issn=2195-9706|doi-access=free }}</ref>

Cornwall is also divided by a number of [[Fault (geology)|faults]] and fracture zones with a preferred orientation of NNW-SSE or ENE-WSW, believed to have been reactivated by post-orogenic extension after the [[Variscan orogeny|Variscan Orogeny]], with the ENE-striking fractures hosting magmatic mineral lodes and ‘elvans’ that were mined throughout the 19th and 20th centuries.<ref>{{Cite journal |last=Alexander, A.C. and Shail, R.K. |date=1995 |title=Late Variscan structures on the coast between Perranporth and St Ives, Cornwall |url=https://ore.exeter.ac.uk/repository/bitstream/handle/10036/3807/Alexander_Shail_1995.pdf |journal=Annual Conference of the Ussher Society, January 1995}}</ref> NNW-SSE striking '[[Strike-slip tectonics|crosscourse]]' faults, which are often long and show evidence of significant displacement, are aligned parallel to the regional maximum horizontal stress and therefore are believed to be the most ‘open’ structures, providing enhanced permeability.<ref>{{Cite journal |last1=Brereton |first1=Robin |last2=Müller |first2=Birgit |date=1991-10-15 |title=European stress: contributions from borehole breakouts |url=https://royalsocietypublishing.org/doi/abs/10.1098/rsta.1991.0114 |journal=Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences |volume=337 |issue=1645 |pages=165–179 |doi=10.1098/rsta.1991.0114|bibcode=1991RSPTA.337..165B |s2cid=123973444 }}</ref><ref>{{Cite journal |last=Puritch, E.; Routledge, R.; Barry, J.; Wu, Y.; Burga, D. and Hayden, A. |date=2016 |title=Technical Report and Resource Estimate on the South Crofty Tin Project, Cornwall, United Kingdom |journal=P&E Mining Consultants Inc. For Strongbow Exploration Inc. Technical Report 295}}</ref><ref name=":1" />

The United Downs wells encountered three main lithologies:
#Killas (a low-grade, regionally metamorphosed and deformed mudstone of the Upper Devonian Mylor Slate Formation<ref>{{Cite web |title=Record details {{!}} Geology of the country around Falmouth : memoir for the 1:50 000 geological sheet 352 (England & Wales) {{!}} BGS publications {{!}} OpenGeoscience {{!}} Our data {{!}} British Geological Survey (BGS) |url=https://webapps.bgs.ac.uk/data/publications/pubs.cfc?method=viewRecord&publnId=19867942 |access-date=2022-04-29 |website=webapps.bgs.ac.uk}}</ref>);
#[[Microgranite]]
#[[Granite]].<ref name=":0" /><ref name=":1" />
The wells also intersected open NW-SE-striking fracture corridors related to the major 'crosscourse' of the Porthtowan Fault Zone.<ref name=":0" /><ref name=":1" />

== Community engagement ==
GEL's community engagement programme has been extremely important for the successful continuation of the United Downs geothermal project. From an early stage it was established that time, effort and a personal approach were crucial to finding the extent of the community and reaching a diverse range of its members. As a result, accurate, up-to-date information has been communicated to a broad range of the community via public visits to the GEL site, external presentations to interested groups, exhibitions at public events, printed flyers, online resources and through the wider media.<ref name=":4">{{Cite journal |last=Charman, J., Law, R. and Beynon, S. |date=2022 |title=Effective Community Engagement: The United Downs Geothermal Power Project, Cornwall, UK |journal=European Geothermal Congress, Berlin, Germany {{!}} 17–21 October 2022}}</ref>

An inclusive and interactive education programme and careers events have also been run by GEL to give an insight into Cornwall's new and growing geothermal power and heat industry to students throughout Cornwall.<ref name=":4" /><ref>{{Cite web |title=Education – Geothermal Engineering Ltd |url=http://geothermalengineering.co.uk/education/ |access-date=2022-04-29 |language=en-GB}}</ref>


GEL also established a significant community fund, supporting sustainable and community-led projects in four local parishes with a shared grant of £40,000. This ensured that the local economy, people and environment benefitted as widely as possible from the project.<ref>{{Cite web |date=2018-12-04 |title=First community grants awarded by United Downs Community Benefit Fund |url=https://www.cornwallcommunityfoundation.com/news/first-community-grants-awarded-by-united-downs-community-benefit-fund/ |access-date=2022-04-29 |website=Cornwall Community Foundation |language=en-GB}}</ref><ref>{{Cite web |date=2018-09-06 |title=CCF announces funding from the United Downs Geothermal Community Fund |url=https://www.cornwallcommunityfoundation.com/news/ccf-announces-funding-from-the-united-downs-geothermal-community-fund/ |access-date=2022-04-29 |website=Cornwall Community Foundation |language=en-GB}}</ref>
⚫
In January 2021 the company agreed to sell 3 [[Kilowatt-hour#Multiples|Megawatt-hours]] a year for 10 years to [[Ecotricity]].<ref>{{Cite web|last1=Src="https://Secure.gravatar.com/Avatar/85685f701ea8d0d268f1b71aaa641f10?s=50|first1=<img Alt=""|last2=amp;d=mm|last3=Srcset="https://Secure.gravatar.com/Avatar/85685f701ea8d0d268f1b71aaa641f10?s=100|first3=Amp;r=g"|last4=amp;d=mm|last5=Says|first5=Amp;r=g 2x" Class="avatar Avatar-50 Photo" Height="50" Width="50" Loading="lazy"> Brianmilnes|date=2021-01-04|title=Sold! The UK's first geothermal electricity to the grid {{!}}|url=https://cornishstuff.com/2021/01/04/sold-the-uks-first-geothermal-electricity-to-the-grid/|access-date=2021-01-07|language=en-US}}</ref><ref>{{Cite web|date=2021-01-07|title=Ecotricity seals 10-year agreement to take geothermal power from Cornish plant|url=https://www.energylivenews.com/2021/01/07/ecotricity-seals-10-year-agreement-to-take-geothermal-power-from-cornish-plant/|access-date=2021-03-15|website=Energy Live News|language=en-US}}</ref>


==See also==
==See also==
Line 105: Line 87:


==External links==
==External links==
*{{Official website|https://geothermalprojects.info/united-downs/}}
*[https://www.uniteddownsgeothermal.co.uk United Downs Deep Geothermal Power website]
*[http://www.geothermalengineering.co.uk Geothermal Engineering website]


{{Portalbar|Cornwall|United Kingdom|Geology|Renewable energy}}
{{Portalbar|Cornwall|United Kingdom|Geology|Renewable energy}}

Latest revision as of 07:57, 17 August 2024

United Downs Deep Geothermal Power is the United Kingdom's first geothermal electricity project. It is situated near Redruth in Cornwall, England. It is owned and operated by Geothermal Engineering (GEL), a private UK company. The drilling site is on the United Downs industrial estate, chosen for its geology, existing grid connection, proximity to access roads and limited impact on local communities.[1] Energy is extracted by cycling water through a naturally hot reservoir and using the heated water to drive a turbine to produce electricity and for direct heating. The company plans to begin delivering electricity (2 MWe) and heat (<10 MWth) in 2024. A lithium resource was discovered in the well.[2]

History

[edit]

The Camborne School of Mines led Cornish Hot Dry Rocks (HDR) project, undertaken in the 1980s at Rosemanowes Quarry, was designed to test the theory of inducing a fracture network within granite to create a geothermal reservoir.[3][1]

Geothermal Engineering was founded in 2008 to specialise in the development of geothermal resources. Project funding was secured over the following five years from the European Regional Development Fund, Cornwall Council and private investors.[4][5][6][7][8][9][10]

GEL drilled two wells into the Porthtowan fault zone between November 2018 and June 2019. The geothermal production well reached a depth of 5,275 m (17,306 ft) and the fluid injection well 2,393 m (7,851 ft).[3][1]

Between August 2020 and July 2021, the wells underwent a series of injection tests to analyse the hydrology within the fractured geothermal reservoir. In addition, in July 2021, full reservoir testing (simultaneous production and injection) was undertaken for seven days.[1] During this process, the reservoir was destressed to prevent microseismic events occurring during long term operation.[1][11] GEL adhered to a strict monitoring, management and mitigation procedure to ensure that any induced seismicity was understood by community members.[12]

In August 2020, the project's operations were further funded by the UK Getting Building Fund. GEL received a share of £14.3 million to demonstrate that lithium could be produced from geothermal brines.[13] As of 2021, project costs were approximately £30 million.

In January 2021, GEL agreed to sell 3 MW of power for ten years to Ecotricity.[14][15] In March 2023, the company received another £15 million in private funding.[2]

Geology

[edit]

The geothermal system employed to generate power at United Downs targeted a radiogenic granite batholith that exhibited enhanced permeability due to its intersection with the Porthtowan fault zone.[16][17][18][19]

The Cornubian granite batholith stretches from Dartmoor to the Isles of Scilly and contains a high concentration of heat-producing isotopes such as thorium (Th), uranium (U) and potassium (K). This natural heat production means that the heat flow at United Downs is approximately double the UK average at 120 mWm−2, and geothermal gradient is around 33-35 °C/km, almost 10 °C/km hotter than large parts of the UK.[1][20]

Cornwall is also divided by a number of faults and fracture zones with a preferred orientation of NNW-SSE or ENE-WSW, believed to have been reactivated by post-orogenic extension after the Variscan Orogeny, with the ENE-striking fractures hosting magmatic mineral lodes and ‘elvans’ that were mined throughout the 19th and 20th centuries.[21] NNW-SSE striking 'crosscourse' faults, which are often long and show evidence of significant displacement, are aligned parallel to the regional maximum horizontal stress and therefore are believed to be the most ‘open’ structures, providing enhanced permeability.[22][23][1]

The United Downs wells encountered three main lithologies:

  1. Killas (a low-grade, regionally metamorphosed and deformed mudstone of the Upper Devonian Mylor Slate Formation[24]);
  2. Microgranite
  3. Granite.[3][1]

The wells also intersected open NW-SE-striking fracture corridors related to the major 'crosscourse' of the Porthtowan Fault Zone.[3][1]

Community engagement

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GEL's community engagement programme has been extremely important for the successful continuation of the United Downs geothermal project. From an early stage it was established that time, effort and a personal approach were crucial to finding the extent of the community and reaching a diverse range of its members. As a result, accurate, up-to-date information has been communicated to a broad range of the community via public visits to the GEL site, external presentations to interested groups, exhibitions at public events, printed flyers, online resources and through the wider media.[25]

An inclusive and interactive education programme and careers events have also been run by GEL to give an insight into Cornwall's new and growing geothermal power and heat industry to students throughout Cornwall.[25][26]

GEL also established a significant community fund, supporting sustainable and community-led projects in four local parishes with a shared grant of £40,000. This ensured that the local economy, people and environment benefitted as widely as possible from the project.[27][28]

See also

[edit]

Geothermal power in the United Kingdom

References

[edit]
  1. ^ a b c d e f g h i Farndale, H., Law, R. and Beynon, S. (2022). "An Update on the United Downs Geothermal Power Project, Cornwall, UK". European Geothermal Congress, Berlin, Germany | 17–21 October 2022.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  2. ^ a b Cariaga, Carlo (8 March 2023). "GEL receives £15 million funding for deep geothermal in UK". Think Geoenergy. Retrieved 8 August 2023.
  3. ^ a b c d Farndale, H. and Law, R. (2022). "An Update on the United Downs Geothermal Power Project, Cornwall, UK" (PDF). PROCEEDINGS, 47th Workshop on Geothermal Reservoir Engineering, Stanford University, Stanford, California, February 7–9, 2022.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  4. ^ "Geothermal power plant gets funds". BBC News. 21 December 2009. Retrieved 30 January 2010.
  5. ^ "'Hot rocks' geothermal energy plant promises a UK first for Cornwall". Western Morning News. 17 August 2010. Retrieved 15 August 2015.
  6. ^ "Drilling to begin for Cornwall geothermal power plant in 2011". The Guardian. 16 August 2010. Retrieved 17 August 2010.
  7. ^ "Geothermal projects get funding boost". The Ecologist. 22 December 2009. Retrieved 30 January 2010.
  8. ^ "UK's first geothermal plant given go-ahead". Financial Times. 15 October 2010. Retrieved 17 August 2010.
  9. ^ "£6 Million Grant For Geothermal Energy Project in Cornwall". Invest in Cornwall. 1 November 2011. Retrieved 2 September 2013.
  10. ^ "Geothermal project on rocks after funding blow". this is Cornwall. 4 April 2013. Retrieved 2 September 2013.
  11. ^ Jupe, A., Law, R. and Farndale, H. (2022). "Implementation of an Induced Seismicity Protocol for the United Downs Deep Geothermal Power Project, United Kingdom". European Geothermal Congress, Berlin, Germany | 17–21 October 2022.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  12. ^ "Seismicity – Geothermal Engineering Ltd". Retrieved 29 April 2022.
  13. ^ "LEP agrees £14M investment". Business Cornwall. 4 August 2020. Retrieved 17 July 2021.
  14. ^ "Sold! The UK's first geothermal electricity to the grid |". 4 January 2021. Retrieved 7 January 2021.
  15. ^ "Ecotricity seals 10-year agreement to take geothermal power from Cornish plant". Energy Live News. 7 January 2021. Retrieved 15 March 2021.
  16. ^ "Geothermal power plant set to become a reality in Cornwall". New Civil Engineer. Emap Ltd. 19 October 2009. Retrieved 30 January 2010.
  17. ^ Halper, Mark (11 October 2009). "We're mining for heat in Cornwall". The Independent. London. Retrieved 30 January 2010.
  18. ^ Rezaie, Behnaz; Rosen, Marc A. (1 May 2012). "District heating and cooling: Review of technology and potential enhancements". Applied Energy. 93: 2–10. doi:10.1016/j.apenergy.2011.04.020. ISSN 0306-2619.
  19. ^ Ozgener, Leyla; Hepbasli, Arif; Dincer, Ibrahim (1 October 2007). "A key review on performance improvement aspects of geothermal district heating systems and applications". Renewable and Sustainable Energy Reviews. 11 (8): 1675–1697. doi:10.1016/j.rser.2006.03.006. ISSN 1364-0321.
  20. ^ Beamish, David; Busby, Jon (24 March 2016). "The Cornubian geothermal province: heat production and flow in SW England: estimates from boreholes and airborne gamma-ray measurements". Geothermal Energy. 4 (1): 4. doi:10.1186/s40517-016-0046-8. ISSN 2195-9706. S2CID 55659348.
  21. ^ Alexander, A.C. and Shail, R.K. (1995). "Late Variscan structures on the coast between Perranporth and St Ives, Cornwall" (PDF). Annual Conference of the Ussher Society, January 1995.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  22. ^ Brereton, Robin; Müller, Birgit (15 October 1991). "European stress: contributions from borehole breakouts". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences. 337 (1645): 165–179. Bibcode:1991RSPTA.337..165B. doi:10.1098/rsta.1991.0114. S2CID 123973444.
  23. ^ Puritch, E.; Routledge, R.; Barry, J.; Wu, Y.; Burga, D. and Hayden, A. (2016). "Technical Report and Resource Estimate on the South Crofty Tin Project, Cornwall, United Kingdom". P&E Mining Consultants Inc. For Strongbow Exploration Inc. Technical Report 295.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  24. ^ "Record details | Geology of the country around Falmouth : memoir for the 1:50 000 geological sheet 352 (England & Wales) | BGS publications | OpenGeoscience | Our data | British Geological Survey (BGS)". webapps.bgs.ac.uk. Retrieved 29 April 2022.
  25. ^ a b Charman, J., Law, R. and Beynon, S. (2022). "Effective Community Engagement: The United Downs Geothermal Power Project, Cornwall, UK". European Geothermal Congress, Berlin, Germany | 17–21 October 2022.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  26. ^ "Education – Geothermal Engineering Ltd". Retrieved 29 April 2022.
  27. ^ "First community grants awarded by United Downs Community Benefit Fund". Cornwall Community Foundation. 4 December 2018. Retrieved 29 April 2022.
  28. ^ "CCF announces funding from the United Downs Geothermal Community Fund". Cornwall Community Foundation. 6 September 2018. Retrieved 29 April 2022.
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