Probing the geothermal potential of Ireland
Abstract
Geothermal power is traditionally viable only in volcanically active regions, however direct application of this energy source for industrial heating can exploit low enthalpy sources buried in the crust. Attempts to examine the geothermal potential of Ireland have been impeded by sparse heat flow measurements and a lack of thermal constraints to apply to rocks, such as thermal conductivity and heat production. Our project seeks to increase the density of heat flow measurements in Ireland to provide new constraints on the temperature field. In addition, we revisit historic heat flow measurements to account for a palaeoclimate correction associated with the last glacial maximum some 15,000 years ago. This has the effect of increasing heat flow values by approximately 15%. We assimilate these data within a novel inversion framework to quantify the uncertainty of subsurface temperature. Additional constraints can be obtained from the depth to Curie temperature – the point at which rocks lose their magnetism (approximately 580°C) – which we computed across Ireland using the recently acquired Tellus airborne magnetic data. Our simulations highlight a gradual increase in subsurface temperature SW to NE and localised heat flow anomalies associated with granite bodies enriched in high heat-producing elements. The uncertainty of these anomalies are, however, relatively high, thus we seek to improve the precision of temperature estimates by resolving finer geological detail and assimilating seismic velocities.
