With the UK’s exposure to global energy uncertainty clear again, attention has turned to what the country can do to strengthen its resilience. Geothermal energy has the potential to be part of the solution, as Michael Chendorain, associate director, global geothermal engineering lead, Arup, explains.
As an energy source, geothermal is able to provide renewable, sustainable, secure and low carbon heat. This capability means it is well placed to dramatically reduce the stress on our already strained electricity grid, and make a valuable contribution to the UK’s energy future.
But while geothermal energy may make a difference in the future, the reality is that this sector is still emerging. High upfront costs, uncertain commercial pathways, and a lack of financial incentives have kept geothermal energy at less than 0.3% of the UK’s annual heat demand. Momentum is starting to build, however, with mine-water and district-heating schemes expanding, and ground-source heat pump (GSHP) installations now exceeding 55,000 systems nationwide.
Setting realistic expectations
The UK has a vastly different geologic profile to traditionally geothermally productive countries like the US, Indonesia, the Philippines, and Turkey, leading to lower expectations for British geothermal energy. The UK does have access to deep geothermal energy for heating across most of the country, however accessing it carries development risks, which temper investor enthusiasm.
The two principal risks related to deep geothermal energy are how productive a system will be, and how much the well drilling will cost. To provide some level of guidance for costs, the Department of Energy Security and Net Zero (DESNZ) has published data on drilling cost ranges. In countries such as Germany and the Netherlands, productivity uncertainty is partially derisked through government insurance schemes, providing reimbursements where productivity is insufficient for commercial success.
While industry waits for the route to deep drilling to be made more accessible, shallow geothermal technologies, particularly GSHPs, can help the UK begin reaping the energy’s benefits. GSHP systems provide a scalable, low-cost route to decarbonising heat. But GSHPs shouldn’t be considered ‘magic bullets’. Further work is needed to ensure geothermal energy can be accessed at scale.
Identifying the UK’s immediate options
Enhanced and advanced geothermal systems (EGS and AGS) are available to the UK which create viable reservoirs in areas without naturally permeable rock, either by stimulating rock
or circulating fluid through closed loops. The challenge with such an approach is that they are costly alternatives which carry additional risks.
More importantly, drilling is becoming faster and more efficient due to polycrystalline diamond compact drill bits.
Recent projects in the US show significant cost reductions, increased output and faster drilling. AI and advanced modelling can optimise performance, while repurposing oil and gas wells may also reduce costs where suitable.
Positively, despite modest geothermal gradients of 27˚C/km, UK projects show that geothermal is viable. Mine-water schemes in the North supply low-carbon heat, while Gateshead’s network serves public buildings and homes. Nottingham University Hospitals NHS Trust is also installing a geothermal system expected to cut 10,000 tonnes of CO2 emissions.
Improving policy and regulation
The UK’s regulatory framework around geothermal is somewhat fragmented, with oversight split between the Environment Agency, the North Sea Transition Authority and local authorities. A unified structure could streamline exploration, licensing and integration into national energy planning. Recent reforms are helping. Heat network zoning supports district-heating rollout; the Environment Agency is clarifying guidance for shallow geothermal systems; and the Mine Remediation Authority has simplified approvals for mine-water schemes.
Ultimately, the biggest barriers are limited awareness and early-stage funding for drilling. Policymakers, developers and the public often underestimate geothermal energy’s viability and low environmental impact. Clear communication about geothermal energy’s contribution to decarbonisation and energy security, alongside transparent project data, will build investor confidence. Industry groups are advocating for the sector, but coordinated messaging is needed to embed geothermal in the national energy discussion.
A dependable energy resource
As the UK looks to strengthen its energy resilience and accelerate decarbonisation, geothermal energy offers a reliable, low carbon and under-utilised solution. The technology is proven – early projects are demonstrating its viability, and innovation is steadily reducing costs and complexity. With the right support, geothermal energy can move from a niche contributor to a meaningful pillar of the UK’s future energy system.
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