The UK’s pathway to net zero hinges on a significant transformation in how we generate and use heat. With heating accounting for over 40% of the nation’s carbon emissions, primarily from fossil fuel-based systems, alternative approaches are essential. Among the technologies poised to make a long-term impact is geothermal energy—a low carbon solution that draws on heat stored beneath the Earth’s surface to supply buildings and infrastructure with reliable, renewable warmth.
Understanding Geothermal for Heat
Geothermal energy refers to the thermal energy generated and stored within the Earth. In the context of heating systems, this heat is accessed through shallow or deep boreholes, with heat extracted via closed-loop or open-loop systems, depending on geological conditions.
In a closed-loop system, fluid circulates through a network of pipes embedded in the ground, absorbing heat from the surrounding rock. This is then upgraded using a heat pump and distributed to end users through a district or building-level heating network. In open-loop systems, water is drawn from deep aquifers, heat is extracted, and the cooled water is returned to the ground.
Unlike surface-based renewable technologies such as solar or wind, geothermal heat is available year-round, day and night, with minimal fluctuation. This makes it particularly attractive for supplying baseload thermal energy in settings with consistent demand—such as hospitals, universities, housing estates, and industrial sites.
The Role of Geothermal in Low Carbon Strategies
Geothermal energy is uniquely positioned to address two central challenges in the decarbonisation of heat: reliability and scale. While many low carbon heating technologies rely on the availability of electricity or weather-dependent conditions, geothermal can provide heat independently of the grid. This is critical for projects located in areas with limited grid capacity or where high electrical demand could delay the adoption of electrified heating systems.
The UK Climate Change Committee has stressed that decarbonising heat is a central requirement for meeting 2050 targets. Star Energy is working to ensure that geothermal is part of the solution. Our modelling and field data show that geothermal systems can provide large volumes of heat at low emissions intensity, typically delivering lifecycle carbon savings of 70–90% compared with gas-fired systems, depending on configuration and heat source temperature.
Subsurface Potential in the UK
Despite being underutilised historically, the UK has significant geothermal resources. A study from Durham University estimates that there is enough geothermal heat within reach of current drilling technology to meet the UK’s annual heating demand for over a century. Temperatures increase at a typical rate of 25–30°C per kilometre depth, with higher gradients in specific regions such as Cornwall, the Cheshire Basin, and the Weald.
Star Energy’s geothermal energy feasibility studies and test borehole data—such as those carried out at Trafford Park in Greater Manchester—have confirmed that many urban and suburban areas are suitable for medium-depth closed-loop systems. Our projects incorporate thermal response testing, geo-exchange modelling, and site-specific geological assessments to ensure the viability and long-term efficiency of each installation.
Applications and Project Deployment
Geothermal systems are especially effective for district heating schemes and larger developments with sustained thermal loads. Our current project portfolio includes:
- Geothermal supply to NHS facilities and public sector buildings
- A major feasibility study in Southampton with Bring Energy to integrate geothermal with the existing district heat network
- Ongoing collaboration with Veolia to deliver geothermal heating to hospitals, campuses, and industrial sites across the UK
The flexibility of geothermal allows it to be integrated into both new developments and retrofit projects. For example, a city centre heat network can be partially or fully supplied by geothermal energy, reducing demand on fossil fuel backup or gas CHP systems.
With support from government-backed facilities and private capital, geothermal is transitioning from niche technology to scalable infrastructure.
Cost, Efficiency, and Long-Term Value
While upfront costs for geothermal heat systems are higher than gas or air-source heat pumps, the operational savings and predictable energy supply offer significant long-term value. Systems are designed for lifespans of 25–50 years, with minimal maintenance and no fuel costs. In addition, the resilience of geothermal to external market volatility means projects are shielded from gas price spikes or electricity shortages.
On a lifecycle basis, geothermal heating has one of the lowest carbon footprints per kilowatt-hour delivered. The embodied emissions are limited to drilling and installation, after which the system produces virtually no direct emissions.
Supporting the National Net Zero Target
As the UK scales up its low carbon heating infrastructure, geothermal energy can play a leading role alongside heat pumps, waste heat recovery, and green hydrogen. Unlike other technologies that are constrained by demand peaks or intermittency, geothermal provides a stable foundation for decarbonised heat networks. With over 90 operational sites and decades of subsurface experience, Star Energy is uniquely positioned to bring commercial-scale geothermal projects to life. Our approach integrates site-specific assessment, engineering, funding, and operational expertise to deliver dependable heat solutions that help clients meet decarbonisation targets.
Geothermal energy is not just a concept for the future—it is a proven, scalable solution for delivering low carbon heating today. As more organisations and local authorities seek to reduce emissions and strengthen energy security, geothermal will become a core component of the UK’s sustainable heat transition.