The United Kingdom’s electricity grid is now incorporating geothermal power, marking a significant development amid a global revival of interest in this energy source. Advances in well technologies and escalating power demands from data centers are key drivers behind this renewed focus.
Cornwall’s United Downs plant, a pioneering facility, is set to produce 3 megawatts of electricity. Concurrently, it will extract lithium, a vital component for battery manufacturing. This dual-output approach highlights a new economic dimension for geothermal projects.
A Geothermal Renaissance
Ryan Law, CEO of Geothermal Engineering Ltd., the company behind the United Downs project, describes the current period as a “renaissance.” He notes substantial activity in the United States and Europe, partly fueled by an insatiable global appetite for 24/7 renewable energy sources.
Traditional renewable sources like wind and solar power are inherently variable, dependent on weather conditions. Geothermal energy offers a distinct advantage by providing a consistent, clean power supply. Its construction timeline is shorter than that of nuclear power plants, and its environmental footprint is smaller than that of hydropower, especially in terms of land use.
Historical Roots and Modern Potential
While geothermal energy was utilized for heating purposes by the Romans two millennia ago and has been harnessed for electricity generation in naturally hot regions like Iceland and Kenya for decades, its contribution to the global energy mix remains modest, currently accounting for less than 1 percent of total demand.
However, projections indicate a significant shift. The International Energy Agency forecasts that geothermal energy could fulfill up to 15 percent of the projected increase in global electricity demand through 2050. This potential output could exceed the combined electricity consumption of the United States and India today.
Navigating Challenges at United Downs
The United Downs facility has mirrored the industry’s historical fluctuations. Tin and copper miners in Cornwall have long contended with water seeping through geological faults in the hot granite bedrock. A prior exploration effort in the 1970s and 1980s, spurred by the oil crisis, briefly included drilling a test geothermal well in the area.
Geologist Ryan Law initiated the United Downs project in 2009 but faced considerable obstacles in securing funding. He characterized the investment landscape as presenting “oil-and-gas risk with a utility return,” which made it unattractive to many investors.
Securing £20 million in grants, primarily from the European Union, enabled the drilling of two wells in 2018 and 2019. These wells reached depths of 2,393 meters and 5,275 meters, surpassing the depth of most contemporary geothermal projects at the time.
Harnessing Earth’s Heat and Mineral Wealth
At these depths, the radioactive decay of isotopes like uranium, thorium, and potassium heats water to 190°C (374°F) under substantial pressure. A pump system in the deeper well draws this superheated water to the surface. The extracted heat is then used to generate steam, which drives a turbine to produce electricity.
Law later identified a secondary resource: lithium. Miners had previously noted the presence of this element in the water brought to the surface. Lithium is a critical material for the production of electric vehicle batteries. The United Downs plant will employ chemically coated plastic beads to extract the lithium from the geothermal fluid.
This extracted fluid will then be processed, flushed with fresh water, and combined with CO2 to produce an initial annual output of 100 tonnes of lithium carbonate powder. The project aims to scale this production to 2,000 tonnes per year. Subsequently, the geothermal fluid will be channeled back down the shallower well, circulating through rock faults towards the deeper well, thereby helping to maintain reservoir pressure.
The addition of lithium extraction, which is projected to generate ten times more revenue than electricity alone, was instrumental in attracting £30 million in private equity investment for United Downs. Law, who holds permits for two additional 5-megawatt plants, believes this mineral extraction component has significantly improved the sector’s appeal.
European Prospects and Advanced Techniques
Geothermal development prospects appear more favorable in European Union countries such as Hungary, Poland, and France compared to the UK. These nations possess geothermal resources closer to the surface. The think tank Ember estimates that these countries could develop 43 gigawatts of geothermal capacity at a cost below €100 per megawatt-hour, a price point competitive with coal and gas.
Frankie Mayo of Ember acknowledges that power grids will continue to be dominated by wind, solar, hydropower, and battery storage. However, she emphasizes the enduring value of predictable, low-carbon energy generation, a role that geothermal can increasingly fulfill.
Geothermal energy is becoming economically viable in areas beyond traditional volcanic hotspots, thanks to techniques adapted from the oil and gas industry, specifically hydraulic fracturing. Fervo Energy, a spin-off from Stanford University in California, is constructing a 115-megawatt geothermal plant designed to power Google data centers in Nevada. This venture has reduced well drilling times from 60 days to 20 days by employing advanced diamond drill bits.
Enhanced Geothermal Systems and Future Viability
Fervo Energy is also utilizing horizontal drilling and high-pressure water injection to fracture the rock formations between wells. This method creates a network of numerous hot fractures, facilitating greater water flow compared to the sparser fractures typically found in vertical-well projects like United Downs.
This approach, known as “enhanced geothermal,” is projected to achieve costs below $80 per megawatt-hour by 2027, making it a feasible option across most of the United States, according to research by Roland Horne at Stanford University and his colleagues. The U.S. administration has maintained a geothermal tax credit first established under a previous government.
The U.S. Department of Energy estimates that geothermal resources could potentially generate at least 90 gigawatts by the middle of the century, representing approximately 7 percent of current U.S. electricity capacity.
Roland Horne notes that while costs may be higher with fracking techniques, the significantly increased energy output—three to four times greater—enhances the economic case, making it competitive with average costs for solar, wind, and natural gas power.
Addressing Concerns and Expanding Adoption
Concerns regarding induced seismicity have surfaced, as demonstrated by a magnitude-2.7 earthquake triggered by an enhanced geothermal plant in Germany in 2009, which necessitated a temporary shutdown. Potential water contamination is another issue that has been raised.
However, Horne maintains that such risks can be mitigated. As more enhanced geothermal projects are developed—with at least six projects exceeding 20 megawatts currently underway in the U.S.—communities and financial institutions are likely to become more comfortable with the technology, according to Ben King at the think tank Rhodium Group.
King suggests that while geothermal may not be universally deployed, it can substantially contribute to the grid, especially as electricity demand triples by 2050 due to the proliferation of new electrical devices and systems.