The UK’s first deep geothermal power plant – capable of generating baseload electricity and extracting battery-grade lithium – has switched on at United Downs near Redruth in Cornwall.
The £50m facility, developed by Geothermal Engineering Ltd (GEL), draws superheated water exceeding 190°C from the UK’s deepest borehole at more than 5km underground. The geothermal heat drives an advanced Organic Rankine Cycle (ORC) system to generate 3 MW of constant, weather-independent baseload electricity. Octopus Energy has signed a long-term agreement to purchase the plant’s output and supply it to the national grid.
High lithium concentrations discovered during water testing have enabled co-production of up to 100 tonnes of zero-carbon lithium carbonate annually for use in electric vehicle and energy storage batteries. The electricity generation process cools the geothermal brine to optimal temperatures for lithium extraction before the fluid is reinjected underground in a closed-loop system.
The United Downs project was delivered in partnership with Exergy International, the Italian technology provider behind more than 500 MW of geothermal capacity worldwide. Exergy designed, engineered, supplied and constructed the ORC power plant, incorporating its proprietary Radial Outflow Turbine technology, which is particularly suited to variable geothermal fluid conditions. The closed-loop binary cycle converts heat to electricity without releasing vapour to the atmosphere, ensuring zero emissions and a minimal surface footprint.
The development highlights Cornwall’s unique granite geology and establishes a new model for integrated geothermal power and mineral extraction, and GEL plans to scale lithium production to more than 18,000 tonnes per annum over the next decade.
Two additional deep geothermal projects in Cornwall are also under development, targeting a further 10 MW of baseload capacity by 2030.
According to the British Geological Survey, onshore geothermal resources in the UK could potentially provide more than 200 GW of thermal energy, underscoring the long-term opportunity for the sector.
