Unlocking the Economic Potential of Minewater Geothermal in Scotland

Abandoned flooded mines can be used as a source or sink of heat. Water in flooded mines is naturally heated from the Earth’s geothermal energy or can be charged with heat from the surface (I.e., from waste heat or renewable energy sources). Warm minewater can be brought to the surface and passed through heat exchangers that transfer the heat to a secondary fluid, which then passes through a heat pump, raising the temperature to provide hot water for heating domestic and commercial buildings. However, if developers, landowners, Local Authorities, or other decision-makers are unaware of minewater then it will not be considered among the low carbon heating options for developments. 

Scottish Enterprise commissioned this research to understand what type of information stakeholders would require to consider minewater as a low carbon heating solution at the earliest stages of their projects. This project engaged with a range of stakeholders from across the project lifecycle to determine their level of awareness and perceptions about minewater geothermal technology.

This study aimed to determine the level of awareness of this nascent technology among industry stakeholders who could be the so-called ‘heat clients’, the parties that would be requiring heat for their developments, such as property developers and landowners, as well as stakeholders who may be involved in the development of future minewater schemes such as supply chain companies or consultancies. 

Published by Katherine Deeming at the University of Strathclyde.
Semi-structured interviews were used to gain deeper insights from the twelve participants and were analysed using thematic analysis.

The results show that the landscape of minewater thermal is very complex with many interlocking elements. A number of themes were discussed, which fall under two categories; issues affecting minewater schemes specifically, and broader issues which could be applied to other low carbon heating systems. Perceived advantages of minewater thermal technology included its use as an inter-seasonal thermal store for district heating networks, and the apparent co-location of minewater resources with heat demand. Perceived disadvantages included the high capital cost relative to other low carbon heating solutions and the pre-construction risks associated with determining the feasibility of the resource. Other themes discussed included skills and labour shortages and the need for regulation for minewater thermal. Wider issues included the high retail cost of electricity being a barrier to the development of all low carbon heating schemes and the vicious cycle between the lack of demand for low-carbon heating and the lack of companies and installers to convert people’s heating systems.

Recommendations arising from this study include, considering minewater thermal as part of a district heating network solution rather than a separate entity. This is especially relevant where mines could be included as a thermal store, which could help to increase the efficiency and resilience of these networks. Another recommendation is the need for a streamlining of regulations associated with developing a minewater thermal scheme. Clarity is needed on subsurface heat ownership and how that will be managed in the future. Wider recommendations include the reform of electricity pricing to enable low-carbon projects to be more economically viable and the installation of domestic low-carbon systems can be a cheaper alternative to gas boilers, aiding in the shift away from fossil fuels.