The story
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.
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.
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).
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. During this process, the reservoir was destressed to prevent microseismic events occurring during long term operation. GEL adhered to a strict monitoring, management and mitigation procedure to ensure that any induced seismicity was understood by community members.
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. 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. In March 2023, the company received another £15 million in private funding.
In September 2023, the results of a contract for difference allocation round were published, in which United Downs Deep Geothermal Power Plant and two other projects by GEL were awarded a strike price of £119/MWh in 2012 prices (equivalent to £164 in 2023).
From Wikipedia’s article on United Downs Deep Geothermal Power, shared under CC BY-SA 4.0.3