Research into the geothermal energy sector in Northern Ireland : geothermal technology and policy review

Arup and the British Geological Survey (BGS) have been commissioned by the Department for the Economy (DfE) to evaluate the current geothermal energy sector in Northern Ireland (NI). This report summarises the work undertaken, including suggestions for changes to policy and regulation which may unlock Northern Ireland’s geothermal resource in the future.
The Energy Strategy for NI [1] recognises that geothermal energy can contribute to the decarbonisation of heating and/or cooling. Heating is a critical component to meet these decarbonisation targets given that currently 68% of homes in NI are heated by carbon emitting oil boilers.
Recent analysis of geological data across Northern Ireland by the Geological Survey of Northern Ireland (GSNI) has identified areas with potential for deep geothermal heating projects, particularly around Antrim and in other areas of deeply buried sediment. In combination with shallow geothermal projects, which have applicability more widely, there is no shortage of options for geothermal development in NI. Demand for heat is equally as important as supply for geothermal projects and there are many industries that could benefit from direct use of geothermal heat, and if feasible, geothermal power (noting that the latter requires very specific geological conditions).
Closed loop geothermal systems are generally suitable at any location (subject to land availability for shallow systems), regardless of the geology. In contrast, open loop systems require aquifers (rock units) from which groundwater can be abstracted for heating/cooling, then returned via boreholes or wells. A schematic conceptual geothermal model illustrating the key geological features found in Northern Ireland and the main geothermal technologies suitable is presented in the figure below. Further detail for all shallow and deep geothermal technologies reviewed for this study is presented in Section 4.