The UK is sitting on 100 gigawatts of thermal energy, equivalent to all of the UK’s current energy demand. BritGeothermal, a new partnership between Durham, Glasgow and Newcastle universities and the British Geological Survey, is working to discover how to best tap these resources. It launched its work today at the British Science Festival.
Subterranean volcanic activity, in places like New Zealand, produces geothermal heat. But even in non-volcanic regions, including the UK, there is substantial geothermal energy. UK geothermal temperatures are cooler, less than 100oC, than in volcanic regions. But still, for every kilometre you drill down below the UK, the temperature rises by an average of 26oC. A new 1.8 km deep geothermal research borehole in the centre of Newcastle reaches temperatures of 73oC, equivalent to a 36oC temperature increase for each kilometre down into the earth, well above the UK average.
BritGeothermal is now investigating how to optimise extracting energy from such geothermal sources. One approach is to find chemicals that boil at less than 100oC, so that “steam” can be made using UK geothermal energy. Dr Charlotte Adams of BritGeothermal commented that “lowering the temperature at which power can be produced could help to provide the economic case of deep geothermal energy.”
The British Geological Survey has mapped the UK’s geothermal hotspots, and located major focussed areas on the South coast and in the East of England.
Southampton has had a functional geothermal bore hole for 25 years. It supplies local industrial and domestic users with 1.8 megawatts of thermal energy. Turning to the North Sea, Dr Adams said “the Brent oilfield is now producing more hot water than oil”.
The increase in energy prices is driving investment and interest in geothermal power sources, said Dr Adams. Geothermal energy has the opportunity to provide a low carbon, predictable, secure energy supply for the UK, though Adams added that “there are many social, technical and economic challenges to explore deep geothermal energy.”