Deep beneath the ancient granite of Cornwall, something extraordinary is happening.
At around three miles underground, the rock is hot enough to boil water. It has been that way for millions of years. And now, for the first time in British history, **Geothermal Engineering Ltd (GEL)** is using that heat to generate electricity — and as a bonus, is extracting lithium from the same superheated brine to make battery materials for electric vehicles.
The result is what the company is calling a **'double first' for the UK**: the nation's inaugural commercial geothermal power, and its inaugural domestic lithium carbonate production, achieved simultaneously at a single site called **United Downs** near Redruth, Cornwall.
**How It Works**
GEL drilled two deep wells at United Downs — one going down at an angle to pump cold water in, the other to capture the superheated brine that comes back up. The returning water, at temperatures exceeding 170°C, is circulated through a heat exchanger that drives an Organic Rankine Cycle (ORC) turbine, generating continuous, low-carbon electricity.
Unlike solar and wind, geothermal power runs 24 hours a day, 365 days a year. No sun required. No wind required. Just the Earth's own internal heat, reliably and endlessly available.
The plant is now capable of supplying electricity to **approximately 10,000 homes**.
**The Lithium Bonus**
But the real surprise is what else came out of the ground with that hot water.
The geothermal brine at United Downs contains elevated concentrations of dissolved lithium — a critical mineral used in rechargeable batteries for electric vehicles and grid-scale energy storage. GEL has installed a **Direct Lithium Extraction (DLE)** system that filters lithium from the brine as it passes through the facility, before the water is returned to the ground.
The result: **zero-carbon lithium carbonate**, made without the open-pit mining, enormous water consumption, and environmental disruption associated with conventional lithium extraction in South America and Australia.
The plant aims to produce **approximately 100 tonnes of lithium annually** in its initial phase — with plans to scale significantly over the next decade. For context, the UK currently imports 100% of its lithium. United Downs is the beginning of that changing.
**Why This Matters for the Energy Transition**
The timing couldn't be better. The UK is committed to ending new petrol and diesel car sales by 2035. That transition requires lithium — enormous quantities of it — for EV batteries. And it requires low-carbon electricity to charge those EVs meaningfully.
United Downs delivers both, from the same hole in the ground, from a county that was once the industrial heart of Britain's mining heritage.
In February and March 2026, the Guardian, Sky News, Renewable Energy Magazine, and the Energy Global trade journal all covered the project's commercial activation. The Hatch engineering firm, which supported the project's development, called it 'a landmark moment for UK energy security.'
**Cornwall's Second Mining Renaissance**
For the people of Cornwall, there's something particularly resonant about this. The county's tin and copper mines — which once powered the Industrial Revolution and employed generations of Cornish families — have been silent for decades. The knowledge, the geology, the culture of going deep into the earth for valuable materials: it never entirely disappeared.
Now it's back. Cleaner. Quieter. And feeding the technology of the 21st century.
The Earth's heat has been waiting beneath Cornwall for millions of years. Britain is finally using it. 🌍⚡
*Sources: The Guardian · Sky News · Renewable Energy Magazine · energyglobal.com · cornwallti.com · Hatch Engineering (February–March 2026)*