| Title | Evaluating Sustainable Heat Recoverable from Mine Water Geothermal Systems: A Critical Assessment of Methodological Applicability |
|---|---|
| Authors | Mylene Receveur, Andres Gonzalez Quiros, Alison Monaghan, Fiona Todd, Jack Cropper, Katie Watkinson |
| Year | 2026 |
| Conference | World Geothermal Congress |
| Keywords | |
| Abstract | Disused flooded coal mines that underlie many highly populated areas worldwide are increasingly used as a low-grade heat source for space heating and cooling, and for seasonal heat storage. This is a proven technology with many systems operating worldwide, but the widespread development of the resource is partly hindered by the difficulty to predict the available heat and how much can be sustainably recovered in the long term. When assessing other geothermal systems, the fraction of heat recoverable is determined with a suite of methods to estimate a recovery factor. The application of such a concept in mine water systems is not straightforward. Mines are anthropogenically modified and extremely heterogenous systems. The heat recovery depends on the complex interplay between the reservoir characteristics (e.g. extent of interconnected galleries, mining voids/overburden permeability), the hydraulic recharge/discharge and the geothermal infrastructure design. In this paper, we examine why existing methods are not directly applicable to mine water settings and the importance of considering a sustainability factor for mine water geothermal potential assessment. We discuss the main factors controlling the sustainable heat recovery in a mine water geothermal system by qualitatively comparing two types of systems: abstraction with discharge and abstraction with reinjection. We use hydraulic and temperature data from the UK to showcase end members. The results can be used to guide towards best practice for the optimisation of heat utilisation and the choice of the most appropriate geothermal infrastructure design. |