Opportunities for geothermal energy extraction

Geothermal energy is the energy stored in the form of heat beneath the Earth’s surface that can be used either for heating or to generate electricity, or both.

There are different ways in which geothermal energy can be exploited. This paper explores ground source heat pumps, deep geothermal plants, and extracting heat from mine water.

Use of geothermal resources is currently limited in the UK. However, several studies have investigated the potential for geothermal in the UK, some examples are listed below. The estimates vary due to the areas of the UK being considered, the depth of drilling considered, and the extent to which the resource is deemed technically and economically recoverable.

• In 2018, a study estimated that the available heat from deep geothermal resources (sedimentary basins, ancient warm granites) and flooded mines was equivalent to approximately 100 years heat supply for the entire UK. 1F[1]
• In 2017, a study estimated that the UK had enough resource that was ‘theoretically available’ to easily surpass all UK energy demand (in 2015) but the amount that was ‘technically available’ was much smaller than the ‘theoretical’ resource and recovery would depend on depths drilled and areas targeted.2F[2]
• In 2013, a Government commissioned Deep Geothermal Review Study by the consultancy Atkins concluded geothermal for electricity generation could meet 4% of annual electricity requirements (in 2013 figures).3F[3]
• In May 2012, a paper by consultants SKM in association with the Renewable Energy Association (an industry trade body) argued that geothermal power could provide 20% of the UK’s electricity and all of the UK’s heat demand.4F[4]

[1]   Gluyas et al., Keeping warm: a review of deep geothermal potential of the UK. Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 232, 2018

[2]   Jon Busby and Ricky Terrington, Assessment of the resource base for engineered geothermal systems in Great Britain, Geothermal Energy, vol 5, 24 February 2017

[3]   Atkins, Deep Geothermal Review Study, October 2013

[4]   SKM, Geothermal energy potential Great Britain and Northern Ireland, May 2012