The United Downs plant in Cornwall – credit, Thomas Frost Photography / Geothermal Engineering Limited © SWNS
The UK’s first geothermal power plant has just begun operations, using hot water from deep underground to create renewable electricity.
The United Downs plant in Cornwall has been in development for nearly two decades, and will now begin providing enough electricity to power 10,000 homes.
Geothermal power generation comes via energy stored in the form of heat beneath the surface of the Earth. The company behind the project, (GEL) Geothermal Engineering Ltd., had to drill the deepest on-shore well ever drilled on UK soil—over 3 miles deep—to source the geothermal fluid that is used for the power plant.
The naturally heated water, exceeding 190°C, generates electricity 24 hours a day, 7 days a week regardless of the weather.
The water will help drive turbines to generate electricity for 10,000 homes but will also provide the UK’s first domestic supply of lithium, a critical mineral used in green technology.
Dr. Ryan Law, CEO of GEL, said the opening of the power plant is a “huge advancement for geothermal power in the UK.”
“Geothermal energy and critical minerals extraction are naturally complementary as they share the same subsurface resource,” Dr. Law explained. “The hot, mineral-rich fluids that generate clean electricity can also be processed to recover strategic materials like lithium carbonate.”
“Therefore, collocating power and mineral extraction plants maximizes investment in the wells, minimizes subsurface disruption, and accelerates the transition to secure domestic supply in both critical sectors.”
GEL have said the water they’ve brought to the surface after drilling contains one of the highest concentrations of lithium in the world.
Lithium carbonate is a key raw material used in the production of rechargeable batteries like those that power electric vehicles and energy storage systems. From its February, 2026 starting point, GEL says the plant has the capacity to produce 100 tons per annum.
Ground source heat pumps are a form of geothermal technology already used in the UK, and in places like Southampton, heating is provided to hundreds of homes via a local network. But the United Downs project has drilled to far greater depths where temperatures are hot enough to generate more than just heat, but actual electricity.
Furthermore, the project has only cost around $59 million to date, funded through private investors and the EU.
Energy provider Octopus Energy has purchased the power generated at United Downs and will deliver it, via the national grid, to about 10,000 homes.
GEL has two other sites it plans to develop into geothermal power plants, and although one additional site has been initially turned down over environmental concerns, the company is appealing.
Greg Jackson, Founder of Octopus Energy, said UK bills are “still too high” and the answer is “more homegrown, renewable energy.”
“For the first time, we’re bringing deep geothermal power to British homes—a clean, constant energy source right beneath our feet,” he said. “Projects like United Downs show how the UK can cut bills and carbon by tapping every ounce of our renewable potential.” UK’s First Geothermal Power Plant Begins Using Underground Heat to Power 10K Homes:
How the new plant could look (Image: Sizewell C)
