Geothermal Engineering Limited (GEL) Launches the UK’s First Deep Geothermal Power Plant

The plan to generate deep geothermal electricity in Cornwall has been nearly 20 years in the making. Cornwall is rightly proud of its tin and copper mining heritage, and the hulking remains of the grand stone engine houses, can be seen all over the county. In keeping with this tradition, Geothermal Engineering Ltd (GEL) has drilled the country’s deepest ever onshore well, at more than three miles below the surface to harness the earth’s natural heat. GEL’s £50m United Downs site will draw up water, super-heated by rocks, reaching extremely high temperatures of more than 190°C, to help drive turbines that will generate power for over 10,000 homes. This deep geothermal electricity plant is the first of its kind in the UK. The term ‘geothermal’ literally means ‘heat from the earth.’  

Geothermal energy is still only a small part of the UK’s renewable energy mix, but interest in the technology has been growing. Unlike wind or solar, geothermal energy can generate electricity continuously, providing a stable source of low-carbon power.

The government has welcomed the launch of this new power plant near Truro, seeing projects like this as a way of bolstering energy security and is also hopeful that it will provide a much-needed economic boost to a deprived part of the West Country. 

Dr Ryan Law, Chief Executive and Founder of GEL, said he was overjoyed at the launch:

“To finally reach this point is exciting and a bit of a relief.”

He told the BBC that geothermal power was “really important” because prices don’t fluctuate like with gas “and unlike other renewable sources like wind and solar we are constantly on 24/7 electricity.”

But delivering renewable energy around the clock to heat and power our homes is not the only good news to come out of this pioneering venture. The water itself was discovered to contain a high concentration of lithium, which can be extracted to produce zero-carbon lithium carbonate and used in the production of car batteries. It will provide the UK’s first domestic supply of lithium; a critical mineral used in green technology. GEL has said that it will produce 100 tonnes of lithium carbonate annually starting from this year which is enough to make 2,500 car batteries. 

Geothermal Engineering Ltd (GEL) said:

“The water brought to the surface contains over 340 parts per million (ppm) of battery-grade lithium carbonate equivalent (LCE) making it one of the highest concentrations of lithium in the world.”
Finding lithium was completely unexpected, Dr law said, “it was just lucky.” 

He added:

"When we tested the water in these very deep wells, we found it is full of lithium. It's a very high concentration of lithium and it's a very clean fluid, so it's a natural thing to do as a by-product from the power."

In simple terms, the geothermal plant generates electricity while the cooling process also allows lithium to be extracted from the water.

Dr Law believes that the production of critical minerals needs to be scaled up in Europe, to reduce reliance on imports from other countries, such as China. China processes more than 60% of lithium globally, the majority of which is destined for electric batteries.

The United Downs power plant went online on 26th of February and started generating 3 MW of electricity, alongside the UK’s first commercial-scale, zero-carbon lithium carbonate production facility.

Generating heat from the earth is not a new concept. We already use heat from shallower depths to warm our homes and businesses in some parts of the UK using ground source heat pumps which are a form of geothermal technology and in places like Southampton heating is provided to hundreds of homes via a local network. 

The principle behind geothermal energy is simple: the deeper you drill, the hotter the rock becomes. Granite is particularly ideal for geothermal technology as it is very effective at holding and conducting the earth’s heat. 

Dr Monaghan, head of geothermal at the British Geological Survey (BGS) explained that:

"You drill deep boreholes into the ground and then fractures within the granite rock are used to circulate the water that picks up the heat that is used for electricity production." 

Geothermal Engineering Limited (GEL) further explains:

"In Cornwall, natural fractures or faults in the rock, known locally as crosscourses, act as reservoirs for hot water within the granite. The naturally high temperatures found in the granite are ideal for geothermal energy production."

The British Geological Survey said the new plant was a "major step forward" for geothermal but high drilling costs could make replicating the project difficult. Because drilling a long way down presents technical challenges and is financially costly this is the first time an electricity plant of this kind has been achieved. The project has cost £50m to date, funded through a mix of private investors and £15m from the European Development Fund.

GEL has signed a power purchase agreement with Octopus Energy, a UK energy generation and supply company that also operates in the U.S. They have agreed to a long-term deal to purchase at least 3 megawatts of electricity which can power 10,000 homes via the national grid.

A spokesperson at Octopus Energy said:

"This project is a genuine gamechanger. For the first time, we're tapping into "always-on" green power in the UK, providing a steady stream of clean, home-grown energy," 

Greg Jackson, founder of Octopus Energy said:

“Bills are still too high, and the answer is more homegrown, renewable energy. For the first time, we’re bringing deep geothermal power to British homes, a clean, constant energy source right beneath our feet. Projects like United Downs show how the UK can cut bills and carbon by tapping every ounce of our renewable potential.”

GEL’s ambitions have not stopped with its United Down’s project. The company has two other deep geothermal sites under development in Cornwall, with those projects expected to deliver another 10 MW of geothermal energy by 2030, with the added potential to produce enough lithium for 250,000 cars a year. This number of cars equates to 65% of the UK’s 2024 Battery Electric Vehicle (BEV) registrations. Officials said the British Geological Survey estimates that more than 200 GW of power generation could be produced from onshore geothermal sources. 

Dr Ryan Law, GEL’s Chief Executive and Founder said that there is potential to expand geothermal energy across the UK to generate large amounts of renewable power. 

"We're effectively tapping into a massive nuclear power station that someone's already built. The resource is gigantic.”

Generating electricity from geothermal is also technically possible in Scotland and the Northeast of England but there are currently no approved plans in place. 

Anne Murrell, head of industry body Geothermal UK said: 

"We have a great energy resource, underneath our feet in the UK, but we're not maximising its potential. The challenges we have include investment, and to unlock investment and increase investor confidence, we need a supportive government policy framework. Geothermal needs to be recognised by government as a key part of our energy strategy," 

She said that the cost of deep geothermal can be compared to other forms of electricity generation, but a lot of the spend is upfront. 

With interest in this sector growing, the government appointed Lord Whitehead as the country's first geothermal minister last year within his role as Minister of State in the Department for Energy Security and Net Zero. In the lead up to the launch of the new power plant he described the switch on as a "groundbreaking moment for UK energy innovation".

At this time, most of the growth in the geothermal industry is focused on expanding shallow geothermal because the costs are a lot lower. There are currently, 30,000 ground source heat pumps in UK homes with the government offering grants to reduce the cost via the Boiler Upgrade Scheme. 

More businesses and councils have started to adopt the technology. One example is Gateshead council using the heat from water in flooded mines to heat hundreds of homes. It is extraordinary to think that it has been estimated that a quarter of homes sit above abandoned coal mines which could be used in the same way.

The United Downs project highlights the growing potential for geothermal energy in the UK as the country looks to expand its portfolio of renewable power sources.

It was developed in partnership with Exergy International, an Italian technology provider with more than 500 MW of geothermal capacity in operation worldwide. GEL is backed by Kerogen-CX and Thrive Renewables plc, with support for lithium development from the UK government’s Automotive Transformation Fund.

Dr. Alan Whitehead said:

“The UK’s first-ever geothermal power is a groundbreaking moment for UK energy innovation, powering thousands of homes with clean, homegrown power. With zero carbon lithium now being produced here in the UK, British businesses are leading the way in securing the materials needed to power the next generation of electric cars.”