The British government’s bid for energy independence has hit a familiar snag: the cost of extracting heat from the Earth’s crust. A new report from the British Geological Survey confirms that geothermal resources beneath the UK are sufficient to meet the nation’s heating demand for centuries. Yet the same report warns that current drilling and infrastructure costs make it one of the most expensive renewable options available. This tension between abundance and cost is now being debated in Westminster, as ministers weigh the long-term strategic value of geothermal against its immediate fiscal burden.
Geothermal energy in the UK is not a single resource but a spectrum. Shallow ground source heat pumps, which exploit stable temperatures a few metres below the surface, are already in use. Deeper systems, tapping into hot rocks at depths of three to five kilometres, could provide high-temperature heat for district networks. The BGS report suggests that enhanced geothermal systems, which involve fracturing rock to create artificial reservoirs, could unlock even more capacity. However, each of these technologies carries high upfront capital costs, with deep drilling alone reaching £5 million per well.
The government’s net zero strategy acknowledges geothermal as a ‘low-regret’ option for decarbonising heat, which accounts for 30% of UK emissions. But the phrase ‘low regret’ betrays a deeper hesitation: we know we will need this energy, but we are not sure we can afford it now. The cost of geothermal electricity generation, for instance, remains at least double that of offshore wind. Yet wind and solar cannot provide baseload heat. They are intermittent, seasonal, and require mass storage. Geothermal offers constant output, independent of weather, and does not require vast land use.
The geographical distribution of geothermal resources also complicates matters. The best hot rock resources lie in Cornwall, the Scottish Highlands, and parts of Northern Ireland, far from the major population centres of the Midlands and southeast. Transporting heat over long distances is inefficient. The alternative is to convert heat to electricity on site, but that sacrifices two thirds of the thermal energy in the process. A more likely path is the development of local district heating networks supplied by geothermal wells, but this requires aligning infrastructure investment with urban planning.
The commercial sector is already responding. Several startups now offer full-cycle geothermal services, from survey to drilling to heat supply. One project in Stoke-on-Trent plans to use deep geothermal to power a ceramics factory. Another in Manchester aims to heat a university campus. These ventures are important proof of concept, but they also highlight the regulatory hurdle: the UK does not have a streamlined licensing regime for geothermal exploration. Oil and gas companies dominate the drilling sector, and their expertise does not always translate to geothermal, which requires different rock formations and temperatures.
The scrutiny now facing geothermal is not unusual. Every new energy technology undergoes a period of intense cost-benefit analysis. The question is whether the government can provide early-stage support through subsidies or risk insurance, as it has with carbon capture and hydrogen. If it does not, the abundant heat beneath our feet may remain as inaccessible as the oil beneath the North Sea once was.
In the meantime, the climate continues to warm. Each year of delay in decarbonising heat locks in further infrastructure emissions. This is the calm urgency that underpins the entire energy transition: we have the technology, we know the resource, but we must reconcile the books of nature and finance. Geothermal is not a silver bullet. It is part of a package that includes heat pumps, hydrogen boilers, and building efficiency. But it is a constant, reliable part. And constant, reliable energy sources are exactly what a grid with increasing proportions of wind and solar requires. The UK government must decide whether abundance at a high price is better than nothing at all.
