The Earth radiates heat. 47 terawatts of continuous thermal energy, a constant flux from the core to the crust. A fraction of that, tapped, could power the United Kingdom for centuries. Yet we drill for gas, burn imported liquefied methane, and fret over windless winter days. The geological reality beneath our feet is an immense, untouched battery. The technology to use it is proven. The obstacle is not physics, but economics and political inertia.
A consortium of geologists and engineers has this week delivered a stark briefing to Whitehall. Their message is simple: Britain sits on a geothermal resource that could supply up to 22% of the nation's current electricity demand by 2050, if we start now. The heat is there. The water is there. The geology is there. What is missing is the capital.
Deep geothermal, specifically enhanced geothermal systems, requires drilling three to five kilometres down, fracturing hot granite, and circulating water to bring heat to the surface. The cost is high. A single plant can exceed £50 million. The return on investment is slow. But the fuel cost is zero. The emissions are near zero. The land footprint is minimal. And once built, a geothermal plant runs at 90% capacity factor, baseload power immune to weather or geopolitics.
Compare this to offshore wind, which the UK subsidises heavily. A wind farm costs billions, runs at 40% capacity, requires backup from gas plants, and has a lifespan of 25 years. A geothermal plant can operate for 50 years or more. The levelised cost of geothermal energy is projected to fall below onshore wind by 2035, if we invest in the first wave of plants.
The barrier is the upfront risk. Drilling is expensive. You might hit 180-degree water, or you might hit dry rock. The industry needs a public-private partnership to de-risk exploration, similar to what Norway did with oil. The Treasury has been reluctant. They see the headline cost. They do not see the stranded asset cost of continuing with gas.
There are already pilot projects. The United Downs Deep Geothermal Power project in Cornwall is the first deep geothermal power plant in the UK, generating 3 MW. It is a proof of concept. The geology extends to Weardale, Cheshire, the East Midlands, and even London. The heat is there. But the rate of progress is glacial.
The climate crisis does not wait for budget cycles. The Earth’s energy imbalance is now 0.6 watts per square metre, trapping heat equivalent to 400,000 Hiroshima bombs per day. Every year of delay means more ice melt, more forest fires, more crop failures. Geothermal is not a silver bullet. It is a piece of the puzzle. But it is a piece we are leaving on the table.
Whitehall must act. A national geothermal strategy, with seed funding and a feed-in tariff, could trigger private investment. The cost is modest compared to nuclear or carbon capture. The reward is a homegrown, clean, baseload energy source that lasts for generations. The science is settled. The technology is sound. The only question is whether the politicians have the will to dig.
