The United Downs Geothermal Project, developed by Geothermal Engineering Ltd (GEL), is nearing completion, with commissioning scheduled to complete in early 2025. The plant will produce the first geothermal power in the UK and is an important case study for the development of geothermal projects both in Cornwall, and across the country. The United Downs site consists of a geothermal doublet with a 5,275m production well and a 2,393m injection well within a faulted and fractured granitic reservoir. The concept, developed by GEL in 2008, builds upon the results of the 1970/1980’s Hot Dry Rocks Programme. Site selection/acquisition and a period of fundraising and permitting occurred between 2010 and 2018. Drilling, testing and stimulation of the wells took place between 2018 and 2021. Testing highlighted significant natural permeability within the reservoir and bottomhole temperatures greater than 180 °C. Furthermore, globally significant lithium concentrations ( greater than 300 ppm) have been identified in the geothermal brines. Construction of the power plant has taken place throughout 2024 and power output to the grid is scheduled to begin in early-2025. In addition to development of the United Downs power plant GEL has explored the potential for the extraction of lithium from deep geothermal brines. The first two phases included a pilot study of direct lithium extraction and a technical and economic feasibility study for the development of a demonstration plant. GEL are completing a third phase of this study, the design and construction of a 100 tonnes per annum (Lithium Carbonate Equivalent) demonstration scale lithium extraction plant (part funded by the Automotive Transformation Fund). Construction of the demonstration plant will complete in early 2025. The results will feed into commercial expansion.

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