The UK Taps Into Geothermal
Fin Whitehouse examines the revolutionary energy project set to take Cornwall into a new industrial era
Almost two years ago, a plume of steam could be seen rising into the fresh Cornish air, a sign of what is promised to be a breakthrough energy project. Formerly one of the greatest copper mining regions in the world, Cornwall is entering a new industrial era – replacing Cornish copper with constant low-carbon electricity. The United Downs Deep Geothermal Power project is being developed by Geothermal Engineering and has received funding from the European Regional Development Fund and Cornwall Council. The project is a power plant that uses hot rocks to produce electricity and heat, otherwise known as ‘geothermal power generation’. This now orthodox method of energy production has been deployed in volcanically active areas of the globe but not yet in the UK. To produce geothermal power, the United Downs power plant will:
- Use two wells drilled into the granite of the Porthtowan Fault Zone
- Pump water from the deepest well (5,275m) where temperatures are anticipated to be 180°C
- Feed the steam produced through a heat exchanger
- Convert the extracted heat into electricity
- Reinject water into the second well to capture more heat.
This cycle then continues, producing constant low-carbon electricity for the grid as well as heat for up to 10,000 people at the new Langarth Garden Village, another exciting project in itself that will establish a new distinctive, green and sustainable community. On Thursday 1 July 2021, plans were announced to build four more geothermal sites in Cornwall by 2026. Not only will this provide a low-carbon source of electricity, it also has the potential to produce hundreds of green jobs in one of the most deprived areas of southern
England. Opportunities for jobs can be found in sectors such as construction, exploration, technology, drilling and maintenance. At a time when the UK is crying out for green jobs and homegrown energy resources, is geothermal power generation an untapped resource? There is certainly potential. It has been posited that geothermal power generation could meet approximately 20% of the UK’s energy demand. One only
needs to look at countries with similar thermal resources as the UK – such as, France and Germany – to see the merit in geothermal. This claim is only bolstered by progressions in Enhanced Geothermal System technologies, which can facilitate geothermal development beyond traditional hydrothermal regions. There are a number of locations within the UK with high potential for geothermal power generation, such as Cheshire and Staffordshire. In countries such as France and Germany, geothermal energy has been shown to offer technical advantages as
well as environmental and economic ones. Geothermal energy is not dependent on weather conditions and can therefore deliver baseload energy, which will assist in balancing more intermittent power generation from renewable sources such as solar or wind. Furthermore, in comparison with other renewable and non-renewable energy sources, geothermal has a small land area footprint and a prolonged lifespan.
The benefits and potential are explicit, so what is the delay? A research briefing from the UK parliament in 2022 stated that there is a lack of information about the application of the technology in the UK, which means that the energy source is not currently considered within the UK’s carbon budget or government strategies. If we wish to see a wider roll-out of geothermal, long-term government support is required to develop demonstration projects and expand the industry. As seen in other sectors, such as offshore wind and low-carbon hydrogen, there needs to be a market framework for geothermal technologies that sets ambitious targets and subsidies which could contribute to rapid cost reductions for geothermal energy systems. However, at present, high upfront capital costs and the geological
risk of not achieving the required temperatures or water flows present major barriers. The introduction of geothermal into the UK’s energy mix by the United Downs Project could prove defining for a UK energy industry that has spent the past 12 months in crisis mode and could prompt a necessary expansion of the industry. Whether this will be the case, only time will tell.
Fin Whitehouse, GradIEMA, is a graduate specialist and scientist at Arcadis