Geothermal power is a rapidly developing form of renewable energy, where heat is harvested directly from the Earth’s crust. One potentially abundant source of this energy is water in disused coal mines, which absorbs heat from the surrounding rock. There are thousands of these mines throughout Britain. With the right approach, Durham Energy Institute estimates that there is enough energy within them to meet the heating demands of every building lying over the coalfields. If achieved, this goal would not only be a significant step towards decarbonising the British economy; it could also provide immense benefits to disadvantaged former mining communities in the region. Read More
In 2020, Durham Energy Institute at Durham University, together with colleagues at the British Geological Survey, launched a new research project to make this vision a reality. Named ‘Geothermal Energy from Mines and Solar Geothermal Heat’, or GEMS, the project was subdivided into three different work packages: focusing on the long-term sustainability of mine geothermal heat extraction; solar-geothermal heat storage; and the social, economic, and policy aspects of the technology.
The first work package was headed by Professor Jeroen van Hunen, and used advanced modelling techniques to simulate the flow of water and transfer of heat within a geothermal mine system. Initially, the researchers developed a modelling framework named the ‘GEMS Toolbox’. The framework can determine how much heat can be extracted from mine water as it is pumped to the surface.
Altogether, van Hunen’s team hopes that the GEMS Toolbox will help future developers of the technology to reach the maximum possible efficiency in energy extraction, while remaining sustainable over many years of operation.
The second work package, led by Dr Zhiwei Ma, focused on a technology combining geothermal with solar energy to store heat for later use – critical for ensuring the system is both reliable and economically feasible. Ma’s team aims to show how the region’s heating demands can be met using these dual storage systems. In particular, they have explored the potential of an innovative sorption heat pump and heat storage cycle to ensure hot water can be delivered whenever it is required.
The third and final work package was led by Professors Simone Abram and Laura Marsiliani. Abram’s team has spent two years studying former mining villages in County Durham. Their aim was to understand local awareness of how mine water could be used as an energy source, and explore the potential involvement of local communities.
Marsilliani led a team looking at the economic case for mine-water heat, and the appetite for this form of heating over other alternatives. This sub-project has found that most people in the region are unfamiliar with the technology, and also believe that their concerns are being ignored, leading to widespread scepticism towards renewable energy projects, like the GEMS project. But when offered alternative systems, mine-water heat is the favourite choice, mostly because of its decarbonisation potential and its connection with mining heritage. To enable such a transformative energy transition, the team’s findings highlight a critical need to rebuilt trust among these local communities, and provide better support for them in the long term.
While there are many challenges ahead, the GEMS researchers are confident that they are by no means insurmountable. Through the project’s coordinated approach, geothermal power from mine water will gain more support, and wider rollout of the technology could soon become a reality.
