Britain’s first geothermal power station is finally powering up in Cornwall, bringing a new form of always-on renewable electricity to the UK energy system.
The plant at United Downs near Truro draws super-heated water from three miles below the surface, where temperatures approach 200C. That heat is used to drive turbines, generating enough electricity for around 10,000 homes and delivering round-the-clock power that does not depend on wind or sunshine.
This is geothermal at a depth and scale never achieved in the UK before. Cornwall’s granite geology makes it uniquely suited to the technology.
Granite holds and conducts heat efficiently, allowing water circulated through deep fractures to absorb enough energy to generate electricity once it returns to the surface. Shallow geothermal already heats buildings elsewhere in Britain – but drilling to this depth is what unlocks power generation.
Getting here has taken nearly 20 years.
Ryan Law, CEO of Geothermal Engineering Ltd, who run the plant said: “Geothermal power is really important for the UK because there are no price fluctuations like with gas and, unlike wind and solar, we are constantly on, 24/7 electricity.”
The project required the deepest onshore well ever drilled in the UK and cost around £50m. Funding has come from a mix of private investors and £15m from the European Development Fund, secured while the UK was still part of the EU.
Those drilling costs remain the biggest obstacle to replicating the model elsewhere.
Alongside electricity, the site is expected to deliver the UK’s first domestic supply of lithium, extracted from the geothermal brine.
Lithium is a critical mineral for batteries and clean technologies, adding strategic value beyond power alone.
The electricity has been sold to Octopus Energy, which will supply customers via the national grid.
Two further Cornish sites are planned, reinforcing the region’s geothermal promise. Whether the technology spreads more widely will hinge on reducing drilling costs
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