The United Downs power plant has officially become the first facility in the United Kingdom to produce electricity using heat from the Earth.
The project, developed by Geothermal Engineering Ltd (GEL) over nearly two decades, required drilling the deepest onshore well in the country to reach depths of three miles.
At these depths, temperatures reach nearly 200°C, providing enough thermal energy to drive turbines for power generation. Unlike intermittent renewable sources such as wind or solar, geothermal energy provides a continuous, 24/7 supply of electricity.
Ryan Law, CEO of GEL, highlighted that this “always-on” capability is crucial for the UK as it avoids the price volatility associated with gas.
The electricity produced at the site has been purchased by Octopus Energy, which will supply it to the national grid to power approximately 10,000 homes. An Octopus spokesperson described the project as a “genuine game-changer” for providing a steady flow of home-grown green energy.
Beyond electricity, the facility marks a milestone as the UK’s first commercial source of lithium carbonate, a critical mineral for electric vehicle batteries. While the site will initially produce 100 tonnes of lithium annually, sufficient for 1,400 vehicles, GEL aims to eventually scale production to 18,000 tonnes per year. The UK government contributed a £1.8 million grant toward the lithium extraction costs.
Monaghan, head of geothermal at the British Geological Survey (BGS), noted that granite’s ability to conduct and hold heat makes it ideal for this technology, though high drilling costs remain a significant hurdle. To date, the project has cost £50 million, supported by private investment and £15 million from the European Development Fund.
While deep geothermal energy is technically viable in Scotland and Northeast England, there are currently no other approved plans for similar projects. Anne Murrell, head of industry body Geothermal UK, stressed that a supportive government policy framework is essential to unlock further investment and maximise the country’s underground resources.
Lord Whitehead, the UK’s first geothermal minister, hailed the plant’s opening as a “groundbreaking moment for UK energy innovation”. GEL is currently moving forward with plans for two additional sites, though it is appealing a rejection for another proposed facility.
