UK’s first geothermal power station begins operation in Cornwall

The United Downs geothermal power plant in Cornwall has officially begun generating electricity, marking the first operational geothermal power station in the United Kingdom. Developed by Geothermal Engineering Ltd. (GEL), the facility represents a significant step in diversifying the country’s renewable energy portfolio.

The project has taken nearly two decades of planning, financing, and engineering work to reach commercial operation. At the heart of the system are deep geothermal wells drilled more than 5 kilometres underground, making them the deepest ever drilled in the UK. These wells access naturally heated groundwater circulating through fractured granite formations beneath Cornwall.

At depths of several kilometres, temperatures reach around 190–200°C. Water is pumped down through an injection well where it is heated by the hot rock before returning to the surface through a production well. The heated fluid then drives turbines to generate electricity before being cooled and reinjected underground, forming a closed-loop geothermal energy cycle.

The plant currently generates approximately 3 MW of continuous baseload power, enough to supply electricity for around 10,000 homes. Unlike solar or wind power, geothermal systems operate 24 hours a day, making them a reliable renewable energy source.

Beyond electricity production, the United Downs project has revealed an additional economic opportunity. The geothermal fluids returning to the surface contain high concentrations of dissolved lithium, a critical material used in electric vehicle batteries and energy storage technologies.

According to GEL, the site will produce approximately 100 tonnes of lithium carbonate per year, enough to manufacture around 2,500 electric vehicle batteries annually. Lithium is extracted from the geothermal fluid after energy generation, allowing the project to combine renewable energy production with mineral recovery.

This integrated approach improves the economic viability of deep geothermal developments, which are typically expensive due to drilling costs. The project required an estimated £50 million investment, funded through a combination of public and private financing and developed in partnership with Italian technology provider Exergy International.

Cornwall was selected because its thick granite formations, natural fracture networks, and historical mining data provide favourable conditions for geothermal circulation. The fractured rock allows heated fluids to flow through the subsurface and reach production wells efficiently.

The launch of the United Downs plant is widely regarded as a proof-of-concept for geothermal energy in the UK, a country not typically associated with high-temperature geothermal resources. Unlike Iceland or New Zealand, where geothermal energy is easily accessible due to volcanic activity, the UK requires much deeper and more expensive drilling to reach suitable temperatures.

Despite these challenges, studies by the British Geological Survey indicate that geothermal resources across the UK could theoretically produce over 200 GW of thermal energy if successfully developed.

GEL is already planning two additional geothermal projects in Cornwall, which together could deliver an additional 10 MW of power by 2030. If successful, these projects may encourage further investment and demonstrate that geothermal energy can contribute to long-term energy security and decarbonisation.

The United Downs facility therefore represents more than a single power plant. It marks the beginning of a new geothermal industry in the United Kingdom, combining renewable electricity generation with strategic mineral production.