Unlocking deep geothermal energy in the UK using borehole heat exchangers

Abstract

In the wake of COP 26, the international community is aiming to reduce carbon emissions by adopting alternative and renewable energy sources. Deep geothermal energy can help to achieve this as it represents a low carbon-emitting energy resource that can provide a constant base load of energy. In the United Kingdom, the development of deep geothermal has been limited due to high geological uncertainty and risk. Past exploration has focused on hot sedimentary aquifers and hot dry-rock granites, with limited success. To mitigate risk and extract heat with a lower reliance on geological properties, such as permeability, new development methods have been conceived using deep borehole heat exchangers, where fluid is circulated in a closed-loop system. Feasibility studies have been undertaken through modelling of deep borehole heat exchangers with the hope that these novel technologies can be used to exploit geothermal energy.