Improving overall resource efficiency enhances energy security. Biogas is an important asset within waste management, transforming a range of organic waste into a higher-value product. By creating integrated partnerships, sector coupling highlights the synergies of Geothermal Energy, District Heating, Industry-CO2, Biowaste and Agriculture. This paper offers a perspective on a novel geothermal methodology for the wellbore reformation of biogas to generate hydrogen production with in situ carbon capture and storage (CCS) and proposes a new disruptive approach with a more immediate, direct and effective route to net zero. The methodology is referred to here as Carbon Injection and Gasification Geothermal (CIGG). The CIGG process combines several processes (i.e., hydrogen generation, carbon capture and biogas upgrading) with low-grade heat geothermal to eliminate process steps, saving process energy, costs, and materials, to create one, combined, sustainable solution. To capture these synergies, a wellbore methane reformation tool is proposed that exploits the natural geo-pressure from geothermal reservoirs and their associated formation fluid (hereafter power fluid). The hot injected CO2 waste stream eliminates the temperature depletion of the formation that is normally associated with geothermal power fluids. The immediate, in situ, downhole capture of CO2 will also enable improved geothermal power efficiencies from any CO2 partially recirculated within the power fluid. With geothermal wells having an expected life span of 15–25 years these synergies will enhance energy security for the long term. The CIGG process is proposed as a true win–win for both the energy economy and environmental stewardship.

As the United Kingdom experiences rising temperatures, the need for sustainable cooling solutions is becoming critical. To meet this challenge, Celsius Energy—a specialist in low-carbon heating and cooling systems—has launched an innovative demonstrator site in Stonehouse, Gloucestershire. The site connects a 4500m² building to the subsurface via a heat pump and a network of shallow inclined geothermal probes.

In summer, the system enables the building to be cooled by transferring excess heat into the ground, where it is stored for future use. In the winter season, the same system extracts the stored energy to provide heating. This bidirectional energy exchange reduces reliance on fossil fuels and supports the decarbonisation of buildings (up to 90% reduction in CO₂ emissions).

At the heart of this solution lies Celsius Energy’s patented drilling technology, which drastically reduces the surface footprint of geothermal systems—requiring only two parking spaces for installation. Recognised by the British Renewable Energy Awards for Innovation, the Stonehouse installation meets 100% of the building’s cooling needs, 84% of heating needs, and reduces annual energy consumption by 67%.

Our presentation will explore the technical configuration of the Stonehouse site, performance data from our system in both heating and cooling modes, and the broader implications for urban energy resilience in a warming climate. As part of the UK’s contribution to the German Geothermal Conference 2025, it highlights how subsurface thermal storage can play a vital role in the energy transition, offering a scalable and replicable model for sustainable building climate control.

Star Energy is applying decades of oil and gas experience to accelerate the development of geothermal heat projects in the UK. As a long-standing onshore operator, we possess a deep understanding of the UK’s subsurface, regulatory environment, drilling and operational risks—skills that are directly transferable to geothermal. Our ability to manage complex planning processes, drill wells under community scrutiny, and operate safely and efficiently gives us a unique advantage in bringing forward low-carbon heat solutions.

The Salisbury geothermal project, located in Wiltshire, exemplifies this approach. The project’s objective is to supply geothermal heat to Salisbury General Hospital. To do this, we have repurposed knowledge, techniques, and supply chains from our hydrocarbon business to target heat extraction from deep (>1,000m) aquifers. Our team has engaged early with stakeholders, conducted extensive geological and geophysical assessments, acquired and interpreted new seismic data and advanced the project with a clear focus on risk reduction and project economics. The project is designed to provide sustainable heat to local consumers and public buildings, demonstrating both environmental and commercial viability.

By adapting a traditional O&G approach to the project workflow, we have created a technical and commercial framework by which deep geothermal projects may be delivered. Star Energy’s model of responsible oil and gas production alongside geothermal development offers a blueprint for accelerating the UK’s decarbonisation goals.

Germany has pioneered the reuse of flooded, abandoned mines for geothermal energy (i.e., to meet heating, cooling, and/ or thermal energy storage demands) since the 1980s. In fact, the first mine water geothermal system to be built in Europe comprised a 350 kW_th installed capacity system used to heat a nursing home in Essen in 1984.

Since then, numerous mine water geothermal projects have been implemented across the country; as of July 2025, the authors are aware of at least 18 that are operational, placing Germany at the forefront of the sector. The latest exciting development is a mine water thermal energy storage (MTES) project in which waste heat from a data centre will be stored in mine workings, providing seasonal heating and cooling to a 5^th generation heat network in Bochum.

Based in the UK, geothermal experts at TownRock Energy have over a decade of experience working on mine water geothermal projects closer to home. These include operating and maintaining the only two privately funded, multimegawatt mine water heating schemes (Lanchester Wines), co-leading an R&D project to demonstrate the “geobattery” concept (Galleries 2 Calories), and a multitude of mine water heat network feasibility studies.

This presentation will provide an overview of the mine water geothermal sector in Germany and discuss some of the key learnings TownRock have gained from their experience establishing the mine water geothermal sector in the UK.

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