Is geothermal energy on the cusp of a global renaissance?

The UK’s electricity grid has begun acquiring its first geothermal energy amid a global resurgence in interest in geothermal energy, driven by improving drilling technologies and growing demand for power from data centres. The United Downs plant in Cornwall will generate 3 megawatts of electricity while producing lithium for battery production.

“Let’s call it a renaissance,” he says Ryan Law, CEO of Geothermal Engineering Ltd., the company behind United Downs. “There’s a lot going on in the US. I think there’s quite a bit going on in Europe as well, driven in part by our insatiable demand for 24/7 renewable energy.”

Because power grids rely on wind and solar generation that varies with the weather, geothermal energy can provide continuous clean energy with a shorter construction time than nuclear power and less environmental impact than hydropower.

Although geothermal energy heated Roman baths 2,000 years ago and generated electricity in volcanic hotspots such as Iceland and Kenya for decades, it currently meets less than 1 percent of global energy demand.

That could soon change. The International Energy Agency says geothermal energy could meet up to 15 percent of expected growth in electricity demand by 2050 and generate more electricity than the US and India use today.

The United Downs facility encapsulated the ups and downs of the industry. Tin and copper miners have long struggled with water seeping through fractures in the hot granite beneath Cornwall, and during the oil crisis of the 1970s and 1980s a test well was drilled in the area in a brief flurry of geothermal exploration. Law, a geologist, started the project in 2009 but had trouble raising money.

“It’s like oil and gas risk with a utility.” [electricity sale] return, and that’s why it wasn’t as popular,” he says.

United Downs eventually received £20 million in grants, mostly from the European Union, and drilled two boreholes in 2018 and 2019 to depths of 2,393 meters and 5,275 metres, deeper than most projects at the time. There, the radioactive decay of isotopes of uranium, thorium and potassium heats water under high pressure to 190 °C (374 °F). A pump in a deeper well draws water to the surface, where it produces steam to spin a turbine and generate electricity.

Law later rediscovered something else the miners had noticed: the water that emerged was rich in lithium, a critical element for electric vehicle batteries. This will be removed with chemically coated plastic beads, flushed with fresh water and injected with CO2 to initially produce 100 tonnes of lithium carbonate powder per year, with the aim of eventually reaching up to 2,000 tonnes. The geothermal fluid will then flow down the shallower well and through fractures in the rock towards the deeper well, maintaining pressure in the reservoir.

Thanks in part to lithium, which could generate 10 times more revenue than electricity, United Downs has managed to raise £30m in private equity investment.

“All of a sudden the mineral complement started to make the sector very attractive,” says Law, who has permits for two 5 megawatt plants.

The outlook is more promising in EU countries such as Hungary, Poland and France than in the UK. They have hot water closer to the surface and could develop 43 billion watts of geothermal power for less than €100 per megawatt hour, similar to coal and gas, according to think tank Ember.

“You’re still looking at energy grids dominated by wind and solar and hydro and batteries,” he says Frankie Mayo in Ember. “But that doesn’t mean predictable low-carbon generation doesn’t have a really valuable role.”

And geothermal power is now becoming economical outside of shallow hotspots thanks to techniques from oil and gas fracking. Fervo Energy, a spin-out from Stanford University in California, is building a 115-megawatt geothermal plant to power Google’s Nevada data centers and has cut the time to drill a well from 60 days to 20 diamond bits.

Also, it was drilling horizontal wells and pumping high pressure water to break up the rock between them. This creates dozens of hot cracks for water to flow through, rather than just a few in a vertical well project like United Downs.

This “enhanced geothermal energy” is expected to Const less than $80 per megawatt hour by 2027, making it viable in most of the US, study says Roland Horne at Stanford University and his colleagues. President Donald Trump’s administration has maintained the geothermal tax credit established during the previous administration.

In the US, geothermal power could generate at least 90 billion watts by mid-century, about 7 percent of current capacity, according to to the Ministry of Energy.

“Your costs are a bit higher if you’re fracking,” says Horne. “But if you’re getting three to four times more energy out of it, it improves the economics and makes it competitive on average with solar, wind and gas.”

A boosted geothermal plant in Germany had to be temporarily shut down after it caused a 2.7-magnitude earthquake in 2009, and there were also concerns about possible water contamination. But Horne says it can be prevented. And as better geothermal power gets built — at least half a dozen projects of more than 20 megawatts are underway in the U.S. — communities and lenders are likely to feel more comfortable, he says Ben King at the Rhodium Group think tank.

“I wouldn’t expect it everywhere, but it can certainly play an increasing role in the grid,” says King, “especially if you look out to 2050, if you have double, triple the amount of electricity that we need because we have all these new things that we’re plugging in.”

topics: