Britain has enough geothermal energy to heat the country indefinitely, cut more than 30% of greenhouse gas emissions and improve national energy security. So why has the UK failed to exploit this energy source while its economic peers are reaping the benefits?

The short answer is that in the mid-1960s, discovery of North Sea oil and gas made Britain negligent in seeking renewable energy sources. While geothermal plays a significant role in heating Paris and many communities and businesses in the Netherlands and Germany, the UK is only now waking up to the potential of this clean energy source. Even in the US, where scepticism over climate change often runs high, investors are piling money into geothermal exploration.

Vladimir Putin’s invasion of Ukraine in February 2022 fully underscored Europe’s risky reliance on Russian gas and oil. Meanwhile, high energy prices, our need to achieve net zero and the cost-of-living crisis has brought the problem into even sharper relief.

Geothermal resources are reservoirs of hot water that exist at varying temperatures and depths below the earth’s surface. It uses available technology, has a global track record and already delivers reliable and sustainable energy to heat some of our homes, businesses and industries.

Professor Jon Gluyas, Orsted/Ikon Chair in Geoenergy, Carbon Capture and Storage in the Department of Earth Sciences at the University of Durham, has known this for decades. He has tried to persuade successive governments to consider the development of geothermal energy.

“We had things very, very easy,” he says. “There was a perception that we could just keep using gas forever, first derived from coal and then from the North Sea. Keeping us warm means that something like 77% of all UK heating is supplied from burning gas.” 

However, the UK stopped being a net exporter of gas, coal and oil in 2003. “Up until February 2022, the attitude was that we can just keep buying gas because it was perceived to be ‘a global market’, which it never was. It is mainly a regional market.”

Now, it seems ministers are starting to listen to Gluyas and other long-standing proponents of geothermal. Launched this year, the National Geothermal Centre (NGC), where Gluyas is a board member, is set to illustrate how the government via its Energy Security Plan can step up the development of geothermal energy as a clear route for a just transition to sustainable heat and power for the UK.

“The UK has sufficient geothermal energy to last at least 100 years and, properly managed, indefinitely because you can't cool down the Earth. We have heat beneath our feet. Every place on Earth could develop geothermal energy as heat and/or power,” Gluyas says.

The UK already has a few concrete examples of the power of geothermal. The Eden Project’s biomes are heated by geothermal energy and Gateshead mine water heat network are some real-world examples of how UK communities can benefit from using the energy source to create a sustainable future.

However, CFOs might find financing a switch to geothermal a complex path to take. Eden Geothermal began its journey into deep geothermal back in 2012, but according to Finance Director and Company Secretary Paul Newcombe, it wasn’t the easiest of journeys to completion primarily because of a lack of an established geothermal industry in the UK and lack of funding. 

“Private funding was impossible because at the time there was just nothing happening in deep geothermal in the UK,” he says. 

The project finally became a reality in 2019 when Eden, with a great deal of help from Cornwall Council, secured a grant from the European Regional Development Fund, together with match funding from Cornwall Council and Gravis Capital Management. After a process of due diligence, supplier procurement and site development, the well was drilled in 2021, and became operational in 2023.

Mining history a boon

However, the geothermal revolution could now be gaining momentum. In fact, Britain’s mining history offers ideal conditions for geothermal exploration by not only repurposing disused coal mines, but also upskilling workers in these industries to work in the geothermal and associated supply chain. 

The UK has 23,000 abandoned mines and, with around a quarter of all housing located on coalfields, the potential of this renewable energy is substantial. With many of these areas some of the poorest in the UK, the geothermal industry could not only provide cheaper renewable heating and hot water, but also boost the economy through a green revolution.

Beyond flooded mines, shallow geothermal applications – enhanced by state-of-the-art heat pump technology – are available everywhere in the UK.

Research from the University of Durham shows that direct-use geothermal energy can be extracted from deep saline aquifers, such as those underlying the Cheshire Basin and Worcester Graben, most of Eastern England, the Central Belt of Scotland and Wessex, where the Southampton District Energy Scheme has been supplying geothermal hot water to customers for more than 25 years. Granite, for example in Cornwall, also provides an ideal foundation for deep geothermal use due to its heat-producing properties.

“Geothermal energy represents an exciting, untapped opportunity for the UK as we transition to net zero,” says Sarah Reay, ICAEW’s Climate Change Manager. “With the potential to provide sustainable, cheap and clean energy, geothermal can significantly reduce our greenhouse gas emissions and enhance energy security. It’s time we harness the heat beneath our feet to power a greener future.”