The Low Enthalpy Geothermal Potential of Shallow Aquifers in Northern Ireland and Northern Scotland

To achieve the Low Carbon Energy Transition and the challenge of meeting Net Zero it is necessary to identify and develop economically-viable, low carbon energy sources that have limited environmental impact. Geothermal energy provides such an opportunity. Despite the considerable potential of geothermal energy, to date there has been little commercial success in the UK. Historically, big capital projects have focussed on power generation in high enthalpy fractured Cornish granites; progress has been steady but slow. Feasibility studies have also addressed deep sedimentary aquifer potential across the UK, but most projects have significant geological risk and high well cost. In contrast, low enthalpy geothermal energy obtained from shallow (<200 m) groundwater sources is relatively low cost and utilises well-established technology. The Closed and Open loop Ground Source Heat Pump (GSHP) industry in the UK is growing, however it is the often the case that development of open loop resources is prevented through poor subsurface understanding.

We aim to establish the low enthalpy geothermal potential of northern Scotland (north of the Central Belt) and Northern Ireland by: a) auditing the shallow geothermal resource across Northern Ireland and northern Scotland, b) grading areas based on their economic heat source potential and, if possible, 3) progressing preferred options to a high-level business case.
To audit the low enthalpy geothermal resource an initial desktop study of the distribution of potential shallow geothermal aquifers will be undertaken. Work will focus on shallow gravel aquifers of Plio-Pleistocene and Quaternary age. The student will utilise base maps and expertise provided by the Geological Survey of Northern Ireland (GSNI) and the British Geological Survey (BGS). Once identified, focus areas will be subject to more detailed study including the use of shallow geophysical techniques to constrain depth to bedrock, gravel aquifer internal properties and fluid content.

Geological field mapping to determine aquifer characteristics will be undertaken. Establishing the depositional environment will be key to assessing characteristics such as porosity and permeability distribution, for example ice contact deltas, glacial outwash sheets and tunnel valleys all have significantly different heterogeneity distribution which will impact volume and aquifer flow rate. A set of screening criteria for shallow aquifer prospects will be developed which as well as geological characteristics will also include environmental (e.g. water disposal mechanisms, salinity and metal content) and economic (e.g. evidence of demand, plus possible water cooling requirements of some industries) aspects.

Following these studies, two or more sites will be selected for further feasibility work including simulation to establish economic potential, with at least one site located in Northern Ireland and one in northern Scotland.
The student will be trained in a range of applicable techniques and will also be exposed to broader analysis of environmental and economic aspects. The project will benefit from quarterly meetings with TownRock Energy, a geothermal energy company, and the expertise of the BGS and GSNI).