Geothermal energy, the heat beneath our feet, is among the most abundant and reliable sources of clean power on the planet. Yet its development has been stymied by high upfront costs and geological uncertainty. Today, the UK government announced a £30 million investment in next-generation geothermal technology, signalling a pivot towards a resource that could supply a significant fraction of the nation’s baseload electricity demand.
The Earth’s core radiates heat at a rate of roughly 44 terawatts, several times humanity’s total energy consumption. But accessing that heat economically has proven difficult. Traditional geothermal plants require specific tectonic conditions: hot rocks near the surface, permeable aquifers, and sufficient water circulation. The UK has limited such resources, with only the Cornwall region offering viable heat in the form of hot granite.
Next-generation geothermal, however, sidesteps these limitations. Enhanced Geothermal Systems (EGS) involve drilling deep into hot, dry rock, fracturing it, and circulating water to extract heat. Closed-loop systems use a sealed pipe to transfer heat to the surface without requiring natural permeability. These technologies could unlock geothermal potential across the UK, even in areas without volcanic activity.
The £30 million fund, administered by the Department for Energy Security and Net Zero, will support pilot projects in EGS and deep geothermal drilling. The aim is to reduce costs from current levels of around £200 per megawatt-hour to below £100 by 2030, making it competitive with offshore wind and nuclear. If successful, geothermal could provide up to 10% of UK electricity by 2050, according to government estimates.
Geothermal offers distinct advantages over intermittent renewables like wind and solar. It operates 24/7, unaffected by weather or season. It also has a small land footprint and low visual impact, with plants often built underground. For the UK, which faces the challenge of decarbonising its grid while maintaining security of supply, geothermal is an attractive baseload candidate.
But challenges remain. Drilling costs can exceed £10 million per well, and the risk of hitting dry or unproductive formations is significant. Recent projects in Cornwall, such as the United Downs Deep Geothermal Power demonstration, have faced delays and cost overruns. The new funding aims to de-risk these investments through shared drilling data and advanced exploration techniques.
Internationally, countries like Iceland, the US, and Kenya have successfully integrated geothermal into their grids. Iceland generates over 25% of its electricity from geothermal, leveraging its unique geology. The UK’s geology is less favourable, but advancements in drilling technology, including techniques borrowed from oil and gas, could still make it viable.
The investment is part of a broader strategy to diversify the UK’s clean energy mix. While wind and solar will remain dominant, geothermal could provide stability. It also complements hydrogen, which relies on cheap electricity for electrolysis. Geothermal plants often produce heat as well as power, enabling district heating networks, as seen in Paris and Munich.
However, the scale of the funding is modest compared to the tens of billions poured into renewables. Critics argue that geothermal remains a niche solution in the UK context. The government counters that a targeted investment now could trigger a learning curve similar to solar panels, which have seen costs drop by 90% over the past decade.
Geothermal energy is a geological certainty. The challenge is not the resource but our ability to extract it economically. The UK’s latest investment is a bet that technology can overcome geology. If it pays off, the heat beneath our feet could become a cornerstone of the country’s clean energy future.
