Geothermal energy is experiencing a resurgence in Cornwall, where pioneering projects are unlocking new opportunities for clean power, heat and critical mineral extraction. Once the site of leading experimental research, the region is now home to the UK’s most advanced deep geothermal developments, demonstrating the potential for geothermal applications at commercial scale.
In January, our team at The National Geothermal Centre (NGC) had the opportunity to visit several leading deep geothermal projects in Cornwall. The region’s geothermal journey began in the late 1970s with the Hot Dry Rock project at Rosemanowes Quarry. Led by Camborne School of Mines and funded by the then UK Department of Energy, this groundbreaking initiative sought to circulate water through fractured granite to generate geothermal energy. While challenges in borehole connectivity limited the project’s success, it delivered valuable insights that have informed subsequent geothermal exploration. Today, the quarry is home to Avalon Sciences, where the original 2.5 km boreholes and associated facilities support the training and testing of energy sector professionals and technologies.
Scaling Up Geothermal Production
Fast-forward 40 years, and Geothermal Engineering Ltd (GEL) has built on Cornwall’s geothermal legacy with its United Downs project. The site features two boreholes, drilled to depths of 5.3 km and 2.4 km, tapping into naturally occurring hot water within deep fracture zones—once a challenge to the Cornish miners, now an asset. Accessing temperatures reaching 170°C, the project will begin generating electricity in spring 2025 using an Organic Rankine Cycle plant. GEL is also pioneering the extraction of lithium carbonate from geothermal brines, adding a strategic mineral supply dimension to its operations.
Cornish Lithium is advancing similar co-production methods, focusing on shallower boreholes of around 2 km. These wells will access geothermal waters at approximately 70°C, providing a sustainable heat source for local food producers and domestic heat networks while extracting lithium for battery production. This dual-purpose approach strengthens the commercial viability of geothermal projects and supports the UK’s ambitions for a secure, domestic supply of critical minerals.
Eden Project: A Model for Geothermal Integration
For the Eden Project, geothermal energy is already delivering tangible benefits. Eden geothermal completed the 5.2 km borehole in 2021, supplying heat to the site’s biomes and large glasshouses, where bananas, coffee, lemongrass and papaya flourish—an unexpected but welcome contrast to the January chill. The project is attracting businesses keen to leverage geothermal heat, with a rum distillery set to relocate to the site.
Innovation and Digital Advancements
The University of Exeter and Camborne School of Mines are playing a crucial role in supporting and driving forward geothermal innovation. During our visit, we explored their Deep Digital Cornwall initiative, which leveraged UK, EU and industry funding to provide SMEs based in Cornwall and Isles of Scilly access to research skills, knowledge, innovation expertise, new datasets and state-of-the-art immersive technology facilities for 3D and 4D data visualisation. In their impressive state-of-the-art visualisation suite, we were able to virtually navigate through former mine workings and geological formations, gaining a new perspective on the region’s geothermal potential.
Enabling Success: Policy and Investment Support
Beyond technological advancements, Cornwall’s geothermal sector has benefited from strong, consistent support from Cornwall Council. Alongside deep geothermal projects, the region is also home to Kensa, a company that has been manufacturing and supplying heat pumps since 1999, further demonstrating the breadth of geothermal applications within the region.
Cornwall’s geothermal projects are attracting investment because they go beyond heat and power generation. The ability to produce electricity enhances their financial viability, with potential Contracts for Difference (CfD) support further strengthening the business case. Meanwhile, the integration of geothermal energy with industries like food production creates mutually beneficial synergies. The co-production of lithium provides additional revenue streams, offering insulation against market volatility and making these projects even more attractive to investors.
By coupling geothermal energy delivery with strategic mineral extraction and industrial symbiosis, Cornwall is demonstrating how the sector can move from niche research to mainstream commercial deployment—setting a precedent for the UK’s net-zero ambitions.
