In a press conference this morning, Energy Secretary Claire O’Brien declared that geothermal energy could supply up to 20% of the United Kingdom’s electricity needs by 2040, describing it as “the sleeping giant of British energy.” The statement comes as new seismic surveys, funded by the UK Research and Innovation agency, identify four major geothermal reservoirs beneath Cornwall, the Peak District, the Weald, and the North Yorkshire Moors.
To understand the scale, consider the earth’s crust as a battery. The heat from radioactive decay and the planet’s core is, for all practical purposes, inexhaustible on human timescales. The UK sits on a thermal gradient that averages 30 degrees Celsius per kilometre of depth. At three kilometres, temperatures can reach 90 degrees in certain granite-rich formations. That is enough to boil water, spin turbines, and feed power into the grid.
The government’s new “Deep Heat Roadmap” commits £250 million in matched funding for exploratory drilling and pilot plants. The first two projects, in Cornwall and Cheshire, will begin next year. The Energy Secretary framed the initiative as a matter of energy security and climate responsibility. “We are sitting on a resource that never stops producing,” O’Brien said. “It is clean, baseload, and it belongs to us.”
The physics is straightforward. Unlike wind or solar, geothermal is not intermittent. A well-maintained plant runs at capacity factors above 80%, comparable to nuclear. The technology has matured: enhanced geothermal systems, which fracture hot rock and circulate water, have been proven in Germany, Iceland, and the United States. The UK’s geology is more complex, but not insurmountable.
Yet obstacles remain. Drilling costs are high, typically £5 million to £10 million per well. The return on investment can be slow, and the initial risk deters private capital. There is also the matter of induced seismicity. The 2018 Preston New Road fracking protests left a political scar. But geothermal operations use lower pressures; the British Geological Survey has assessed the risk as low for the designated sites.
The climate math is brutal: the UK must reduce emissions by 68% by 2030 relative to 1990 levels. We are on track to miss that target. Every gigawatt of thermal capacity we install displaces natural gas. Geothermal could provide 5 GW of electricity and 15 GW of heat by 2050, according to the Royal Academy of Engineering. That is roughly seven nuclear reactors’ worth of clean, constant power.
Meanwhile, the biosphere continues to degrade. We are watching ecosystems unravel in real time: coral bleaching, ice sheet collapse, insect die-offs. The planet does not care about our political squabbles. It responds to physics. And the physics says we must decarbonise rapidly within the next decade.
Geothermal has not historically been a major part of the UK conversation. The hot rocks were there, but we lacked the will and the drilling data. That is changing. The new surveys are open access, meaning any company can use the 3D models to plan projects. A small industry is already forming: Geothermal UK, a trade body, has grown from 12 to 47 members in two years.
Will this alone save us? No. But it is one of several tools we must deploy aggressively. Alongside offshore wind, nuclear, demand reduction, and carbon capture, geothermal can help fill the gaps. The Energy Secretary’s language matters. It signals a shift in the Overton window. Leaders are supposed to lead. They are supposed to understand the scale of the crisis. And they are supposed to act with the calm urgency that the moment demands.
We have the science. We have the technology. What we have lacked is the collective nerve. Perhaps, beneath our feet, we are about to find it.
