The Society of Petroleum Engineers, London Branch in the UK, provides a key feature on geothermal energy in the UK in its November/ December 2019 e-magazine.
Under the title “Geothermal energy: is it coming of Age?”, the article asks if one simply has run out of excuses for not developing geothermal resources.
With a decline of UK’s hydrocarbon resources, the article sees the potential for geothermal energy potentially being the solution to fill the energy void. It describes therefore also the “considerable” overlap in the technical skillset of the UK’s oil industry with what would be required for geothermal development.
In the article. Dr. Jon Busby, geothermal specialist at the British Geological Survey discusses how geothermal could help cut carbon emissions.
He describes essentially three classes of geothermal resources of the United Kingdom, deep onshore sedimentary basins where rocks with advantageous porosity and permeability are found at sufficient depth for the temperature to be high enough for direct use applications, such as greenhouse heating, balneology and district heating
The second category he describes are geothermal resources found in tighter sandstones and carbonates of Carboniferous and Devonian age where secondary fracture permeability is often the dominant pathway for fluid flow. These – so the author could be particularly significant resources for district heating schemes.
The third category would be resources with temperatures in excess of 160 centigrades, at a depth of 5,000 meters. These resources can be found in radiogenic granites of the UK, with the most prospective granite to be found in Cornwall, in the southwest of England with an expected temperature of 200 centigrades at a depth of 5,000 meters. This is also where the UK’s first geothermal power project has recently started drilling, as we reported. These type of resources though would require enhancement of natural permeability by stimulation (EGS), as described by Dr. Busby.
And another possibility for the UK to utilise geothermal energy would be via an electric transmission cable from Iceland, delivering geothermal electricity to the UK.