UK generates its first geothermal electricity at United Downs

What happened

In February 2026, the United Downs plant in Cornwall began generating the UK's first geothermal electricity. The project, developed by Geothermal Engineering Ltd (GEL), draws water at more than 190°C from a well over 5km deep — roughly three miles, and the deepest ever drilled on UK soil. The plant produces about 3MW gross, enough for some 10,000 homes, sold to Octopus Energy under a long-term power purchase agreement.

The same brine yields a second product. From February 2026 the site is producing around 100 tonnes of lithium carbonate a year from geothermal waters carrying more than 340 parts per million of lithium — among the highest concentrations recorded, and described by the project team as better than anything seen across Europe.

ITV reported the project cost at £50m, with a contract-for-difference price of £119 per megawatt hour in 2012 prices. Thrive Renewables provided the first commercial funding in 2020, with further investments in 2023 and 2025 to complete construction.

The technology

United Downs exploits the heat held in Cornwall's deep granite. Hot water is drawn up the production well, passed through an Organic Rankine Cycle turbine, supplied by Italy's Exergy International, which has more than 500MW of ORC plant operating worldwide, and reinjected in a closed loop.

Because the heat source is continuous, the plant delivers baseload output around the clock, a property no other UK renewable except biomass can claim. GEL's founder and chief executive Dr Ryan Law described it as "effectively tapping into a massive nuclear power station that someone's already built".

The lithium extraction runs downstream of power generation: after heat is taken off, lithium is recovered from the brine before reinjection, producing technical-grade lithium carbonate with no mining, using the plant's own zero-carbon energy. Current output of 100 tonnes a year is modest, equivalent to roughly 2,500 car batteries, but GEL targets more than 18,000 tonnes a year within a decade, enough for about 250,000 EV batteries annually, or 65 per cent of the UK's 2024 battery-electric registrations.

Why it matters for UK & Ireland

The UK has debated deep geothermal for decades; United Downs converts the debate into megawatt hours. A domestic source of firm, zero-carbon baseload arrives just as the grid wrestles with the costs of intermittency — and 3MW, while small, establishes the drilling, reservoir and generation model at commercial terms, with a household-name offtaker. Octopus founder Greg Jackson framed the purchase bluntly: "Bills are still too high, and the answer is more homegrown, renewable energy."

The lithium is arguably the larger strategic story. UK battery supply chains depend on imported lithium, typically carrying a heavy carbon and water footprint. Co-producing lithium from the same wells transforms project economics, two revenue streams from one drilling campaign, and gives the UK a route to home-produced, low-carbon battery raw material.

GEL cites potential for over 200GW from UK onshore geothermal resources; that is a resource estimate, not a pipeline, but even a small fraction would be material.

For developers and policymakers in Ireland weighing geothermal's potential, a commercially operating plant one sea away is now the nearest proof point.

What to watch

Plant availability through its first full year — baseload claims are won in operation, not at ribbon-cuttings. GEL has two further Cornish projects in development, targeting 10MW of additional baseload by 2030; drilling schedules and funding for those will show whether United Downs is a first or a one-off.

On lithium, the leap from 100 to 18,000 tonnes a year implies substantial new wells and processing capacity, watch for offtake agreements with battery makers as the earliest signal of commercial traction. And watch government: a minister attended the switch-on, and whether policy support follows for geothermal heat and power will shape how fast the sector scales.