Heat from Mines feasibility study, West of England

A number of supporting studies predated the Heat from Mines project, illustrating the desire from WEMCA to progress change at pace for the communities and places in the local area.

• Vast quantities of sites to screen at the beginning, and information to digest from the client, including previous studies.
• Mines across the region are particularly poorly characterised due to their age and complex geological structure, increasing subsurface uncertainty at the desktop stage.
• Constantly developing future plans for sites meant that understanding client priorities was key from the outset.
• Mines in this area have not yet been reused for geothermal energy or storage, so all designs were first-of-a-kind.

TownRock Energy were commissioned by the West of England Mayoral Combined Authority (WEMCA) to conduct a detailed desktop study evaluating the suitability of mine water for heating, cooling, and thermal energy storage at five different sites across the southwest of England. TRE delivered a fully informed decision-making framework to aid the client when progressing the chosen sites for the next stage of development – exploratory drilling.

By investigating the history, geometry, and characteristics of the local coal mines via literature and mine abandonment plans, a conceptual model for each site was developed to communicate the subsurface setting to the client. This enabled numerical modelling to be conducted using GEMSToolbox software and TRE’s in-house Heat In Place tool, to forecast the thermal resource.

Supported by these results, the following was provided to the client:

• Optimal proposed system locations, sizes and designs for each site.
• Bespoke capital cost estimates based on the TRE in-house drilling costing tool.
• Operational cost estimates with predicted carbon savings based on the system capacity.
• Costs normalised to “per MW” for comparison between sites.
• An overview of risks associated with each site and proposed system.
• An outline of the regulatory pathway required from project conception to operation.

TRE selected subsurface criteria to compare the five sites across, e.g., scale of opportunity, depths, temperatures, drilling complexity, costs, CO₂ savings. The criteria were then weighted to favour factors which minimise operational and permitting risk. The favourable site was recommended based on the weighted factors and proposed to the client for development. Fortunately, it was concluded that a system could feasibly be developed at any of the five sites.

TRE have continued to assist the client when planning next steps beyond the Discover Phase. This has included providing guidance for Principal Designer processes and costs for the drilling and delivery of a system.

TRE aspire to support clients from the beginning of their geothermal journey, through installation and operation of a fully functioning system. TRE are positioned to support with operation and maintenance across the full lifespan of the system.