Nana Banana
The official switch-on of the Cornish plant on Thursday morning culminates nearly two decades of intensive development by Geothermal Engineering Ltd (GEL). This ambitious undertaking involved drilling the deepest on-shore well in the UK, a testament to the engineering prowess and perseverance required to tap into this subterranean energy source. The project represents a "major step forward" for geothermal energy, as acknowledged by the British Geological Survey (BGS), even as they caution that the substantial drilling costs could pose challenges for replicating such initiatives across the country without robust support.
Geothermal energy fundamentally relies on the Earth’s internal heat. Our planet continuously generates heat, which can be accessed by drilling wells deep below the surface, providing a constant, renewable source of energy for both heating and electricity generation. The principle is simple: the deeper one drills, the hotter the temperatures become. While shallower depths offer sufficient heat for domestic and commercial heating – a technology already employed in parts of the UK through ground source heat pumps or district heating networks like the one serving hundreds of homes in Southampton – deep geothermal targets much higher temperatures.
The United Downs project exemplifies deep geothermal technology, having drilled to extraordinary depths of three miles (approximately 4,800 meters) below the surface. At these profound levels, temperatures can soar to nearly 200°C. This immense heat is then utilized to drive turbines, converting thermal energy into electrical power. Dr. Monaghan, head of geothermal at the BGS, elaborated on the process: "You drill deep boreholes into the ground, and then fractures within the granite rock are used to circulate the water that pick up the heat [that is] used for electricity production." Cornwall’s geology, rich in granite, is particularly well-suited for this technology due to granite’s exceptional ability to retain and conduct the Earth’s heat efficiently.
Achieving this feat in the UK has been both a technical and financial odyssey. The £50 million investment required to date underscores the significant upfront capital expenditure involved in deep geothermal projects. This funding has been a blend of private investment and a substantial £15 million contribution from the European Development Fund, a mechanism the UK had access to as a member of the European Union. Ryan Law, CEO of GEL, expressed his profound satisfaction to the BBC: "[I’m] tremendously excited after 15 years of hard graft, difficulties, we’re finally there." He emphasized the critical importance of geothermal power for the UK, highlighting its independence from volatile gas prices and its distinct advantage over other renewables like wind and solar: "And unlike other renewable sources like wind and solar we are constantly on, 24/7 electricity." This "always-on" characteristic makes geothermal an ideal source for baseload power, providing a stable and continuous supply to the national grid.
The electricity generated at the United Downs site has been secured by Octopus Energy, which will distribute it via the national grid to power up to 10,000 homes. An Octopus spokesperson lauded the project, stating, "This project is a genuine game-changer. For the first time, we’re tapping into ‘always-on’ green power in the UK, providing a steady stream of clean, home-grown energy." This partnership not only provides a reliable energy source but also contributes significantly to the UK’s clean energy targets and energy security.
GEL’s ambitions extend beyond United Downs. The company has plans to develop two additional power plant sites, although one proposed site has faced initial rejection due to environmental concerns, prompting an appeal. The potential for deep geothermal is not confined to Cornwall; regions like Scotland and the Northeast of England also possess suitable geological conditions for generating electricity from geothermal sources. However, as of now, there are no approved plans for development in these areas.
Anne Murrell, head of the industry body Geothermal UK, articulated the broader challenge: "We have a great energy resource, underneath our feet in the UK, but we’re not maximising its potential." While the operational costs of deep geothermal are comparable to other forms of electricity generation, the substantial upfront investment remains a barrier. Murrell stressed the need for a supportive policy environment: "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."
In a promising sign of growing governmental interest, Lord Whitehead was appointed the country’s first geothermal minister late last year. Ahead of the United Downs switch-on, he hailed it as a "groundbreaking moment for UK energy innovation," signaling a potential shift towards greater recognition and support for the sector.
While deep geothermal for electricity is gaining traction, the growth in the wider geothermal industry is currently more concentrated on shallow geothermal applications, primarily due to lower costs. There are approximately 30,000 ground source heat pumps installed in UK homes, with government grants available to mitigate installation expenses. Businesses and local authorities are also embracing this technology; Gateshead Council, for example, utilizes heat from flooded abandoned coal mines to warm hundreds of homes. It is estimated that a quarter of UK homes are situated above former coal mines, presenting a vast, untapped resource for similar heating schemes. On a larger scale, the Netherlands has set an ambitious target of heating a quarter of its homes using geothermal energy by 2050, demonstrating the significant potential of the technology.
Internationally, investment in deep geothermal for electricity is surging. The International Energy Agency (IEA) reported an 80% year-on-year increase in global investment since 2018. This growth is partly driven by the burgeoning electricity demands of tech giants. "Data centres have major power needs, and we all know that this is very challenging for our current and future anticipated grid," explained Ms Murrell. Companies like Google, Meta, and Microsoft are actively exploring geothermal solutions to power their data centers, with some even integrating systems to send the excess heat produced by these centers back underground for storage or reuse.
Beyond electricity, geothermal projects offer another crucial benefit for the green transition: the extraction of important minerals. The United Downs site will not only generate heat and electricity but also recover lithium carbonate from the geothermal fluid. This marks the UK’s first commercial source of this "critical mineral," essential for the production of electric batteries that power everything from smartphones to electric vehicles. Initially, the site is projected to produce 100 tonnes of lithium annually, enough for the batteries in approximately 1,400 electric vehicles. However, GEL has ambitious plans to scale this output significantly to 18,000 tonnes per year. The UK government has shown its commitment to this aspect of the project, providing a £1.8 million grant, covering 50% of the initial lithium extraction costs. This dual capability positions deep geothermal as a multifaceted solution, addressing both the UK’s energy needs and its strategic mineral security in the rapidly evolving landscape of green technology.
atisusanti
Nakalama John
George Anjay
