GIS analysis for the selection of optimal sites for mine water geothermal energy application: a case study of Scotland's mining regions

Water within flooded coal mines can be abstracted via boreholes or shafts, where heat can be extracted from (or rejected to) it to satisfy surface heating (or cooling) demands. Following use, water can be reinjected into the mine workings or discharged to a surface water receptor. Four criteria have been applied, using ArcGIS, to datasets describing mine workings and mine water below the Midland Valley of Scotland to provide an initial screening tool for suitability for mine water geothermal energy exploitation. The criteria are: (i) the presence of two or more worked coal seams below site; (ii) the absence of potentially unstable shallow (<30 m) workings; (iii) a depth to mine water piezometric head of less than 60 m; and (iv) a depth of coal mine workings of less than 250 m. The result is the Mine Water Geothermal Resource Atlas for Scotland (MiRAS). MiRAS suggests that a total area of 370 km(2) is 'optimal' for mine water geothermal development across 19 local authority areas, with greatest coverage in North Lanarkshire. This result should not be taken to suggest that mine water geothermal potential does not exist at locations outside the identified 'optimal' footprint. The MiRAS does not preclude the necessity for specialist engineering and geological input during a full feasibility study.