Optimisation of thermal energy storage in abandoned flooded mine workings

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Thermal energy efficiency and sustainability is a major challenge, particularly for countries such asScotland where heating represents nearly two thirds of overall energy demand. Abandoned floodedmines are present over vast areas of the UK and typically represent high-level environmental andfinancial liabilities. However, these remnants of our carbon-intensive industrial past also provide anexciting opportunity to develop sustainable low-carbon energy resources through geothermal energy production and thermal energy storage. This project will develop innovative strategies for evaluating the geothermal potential of flooded mine workings.Thanks to Glasgow's extraordinary industrial heritage, many parts of the city, including the University, are positioned over a large network of abandoned, flooded coal mine workings. This project will use the University of Glasgow (UoG) as its major case study. The UoG has a campus wide Combined Heat and Power (CHP) district heating scheme which heats buildings, generates a large percentage of campus electricity and makes a significant contribution to the UoG's carbon footprint reduction target (20% per year). Efforts are underway to achieve further carbon emission reductions for the current scheme and to ensure low-carbon energy for a £1 billion plus campus expansion.As to be expected with the local climate, the campus has a seasonally high heat demand in the winter months. Excess 'waste' heat generated by the existing CHP system could potentially be turned into a valuable resource to help meet campus winter heat demand if it could be successfully captured and stored. A major challenge for heat storage is the capacity required to store enough useable heat for a long enough duration. Due to the warm embrace of the surrounding geology, the flooded mine workings insulate groundwater from seasonal variations in surface temperature. Add to that the enormous volumes of water involved (several million m3), and these flooded mine workings represent a fantastic opportunity for inter-seasonal thermal energy storage if their hydrological nature can be robustly characterised.