The United Downs geothermal project is owned and operated by Geothermal Engineering Ltd (GEL) and is the first geothermal electricity project in the UK. The site was selected in 2010 for its geology (strongly faulted, radiogenic granite), surface infrastructure, grid connection and potential community acceptance. The deep drilling programme started in 2018, with the production well drilled to 5,275m MD and deviating from 3,390m to a final inclination of 33.5o, representing the deepest onshore well in the UK. The injection well was then drilled to 2,393m MD, deviating from 1,020m to a final inclination of 40o. The drilling of a deep production well and shallow injection well into a natural fault zone is a novel concept developed by GEL, based on some of the results from research at the Hot Dry Rocks project in Rosemanowes, Cornwall. The production well has successfully encountered temperatures of 180oC, world-class lithium concentrations and significant permeability horizons within the fault zone. It is expected to provide 2-3MWe to the National Grid during 2023 and carbon neutral heat to local businesses. The project has also been associated with a number of world leading research institutions. Despite the slowdown caused by the Covid-19 pandemic the United Downs project has seen a number of exciting milestones, including completion of drilling, extensive well testing, and signing of the first Power Purchase Agreement (PPA) for deep geothermal electricity in the UK with Ecotricity. The team has also secured grant funding for a demonstration plant that will trial Direct Lithium Extraction (DLE) from the deep geothermal fluid. This paper presents an overview of the initial results of drilling and testing, briefly highlighting the success of hydraulic stimulation and management of induced seismicity during development. It also provides a forward look to the final stages of the United Downs development and the future of geothermal power projects across Cornwall.

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