Geothermal energy facts

Geothermal energy, which harnesses the Earth's continuous internal heat, offers a reliable and renewable power source for the United Kingdom. This energy is available across the UK, from depths of a few metres to several kilometres, and can be extracted using various technologies. Despite its significant potential, the UK currently uses only a small fraction of its geothermal resources, presenting a substantial opportunity to increase its contribution to the national energy mix.

Geothermal energy offers a consistent, low-carbon heat source. Discover how Fuse Energy can help you manage your home's energy efficiently, no matter the source. Click here to switch to Fuse Energy today.

What is geothermal energy?

Geothermal energy is the heat stored beneath the Earth's solid surface. It is a constant, low-carbon, and renewable source of heat that operates independently of weather conditions, unlike intermittent renewables such as wind or solar. This makes it a valuable asset for energy security and reducing reliance on imported fuels.

Harnessing Earth's internal heat

The Earth's core generates immense heat, which continuously radiates outwards. Geothermal systems tap into this heat by accessing underground reservoirs of hot water or steam. The temperature beneath the ground surface increases with depth, a rate known as the geothermal gradient. In the UK, this gradient typically ranges between 25-30°C per kilometre of depth, meaning temperatures increase significantly with depth. This natural heat flow can be captured for various uses.

Constant and low-carbon energy source

Unlike many other renewable sources, geothermal energy is "always on," providing continuous production 24 hours a day, seven days a week, 365 days a year, regardless of weather or season. This makes it a highly predictable and stable energy source, crucial for maintaining grid stability and meeting baseload demand. It also produces minimal greenhouse gas emissions, contributing significantly to decarbonisation efforts.

Geothermal potential in the UK

The United Kingdom possesses significant, largely untapped geothermal resources, challenging the common misconception that geothermal energy is only viable in volcanic regions.

UK's geological resources

The UK has substantial geothermal potential, particularly in regions like Cornwall, known for its granitic areas, and deep sedimentary basins such as the Wessex and Cheshire basins. Cornwall's granites, for instance, exhibit abnormally high geothermal gradients due to naturally occurring radiogenic elements, making them promising for both heat and electricity generation. Deep geothermal resources in the UK could potentially meet a very significant portion of the nation's heat demand.

Existing geothermal projects: a UK perspective

While the UK's geothermal potential is vast, current deployment is modest. However, existing projects demonstrate long-term viability. The Southampton District Heating Scheme, for example, has been utilising geothermal energy for heat since 1986, drawing hot water from the Wessex Basin aquifer. This scheme provides heat to various city centre buildings, including residential properties, and stands as a testament to geothermal's practical application in the UK. Other projects, such as those in Cornwall, are also advancing, with plans to generate electricity and heat from deep geothermal resources.

How geothermal energy works

Geothermal technology can be adapted for both electricity generation and direct heat use, making it versatile for decarbonisation goals.

Deep geothermal systems for power and heat

Deep geothermal systems involve drilling wells several kilometres into the Earth to access high-temperature reservoirs. For electricity generation, hot water or steam from these reservoirs drives turbines. For direct heat use, the hot water is circulated through heat exchangers to provide heating for homes and businesses via district heating networks. The cooled water is then reinjected into the Earth, ensuring the resource is replenished.

Geothermal gradient and heat flow

The Earth's internal heat continuously flows outwards, creating the geothermal gradient. This gradient is higher in some geological formations, such as the granites of Cornwall, where temperatures can reach very high levels at significant depths, sufficient for power generation. In sedimentary basins, temperatures are typically lower but still suitable for direct heating applications. Understanding these geological conditions is key to effectively harnessing geothermal energy.

Benefits of geothermal energy

Geothermal energy offers significant advantages for the UK's energy landscape, contributing to reliability, environmental goals, and energy independence.

Reliable baseload power

One of the most compelling benefits of geothermal energy is its ability to provide continuous baseload power, operating 24/7, which perfectly complements intermittent renewable sources like wind and solar. This constant output ensures a stable and predictable supply of energy, reducing the need for fossil fuel backups and enhancing grid reliability, which can contribute to overall energy bill savings.

Environmental advantages and decarbonisation

Geothermal energy is a low-carbon alternative to fossil fuels, significantly reducing greenhouse gas emissions. Its deployment contributes directly to the UK's decarbonisation targets, particularly in the heating sector, which accounts for a large portion of national energy demand. By utilising the Earth's natural heat, geothermal systems minimise air pollution and have a smaller land footprint compared to many other energy sources.

Energy security and independence

By tapping into indigenous geothermal resources, the UK can reduce its reliance on imported fuels, strengthening energy security and independence. This domestic energy source is not subject to geopolitical fluctuations or volatile international markets, providing a stable and predictable component to the national energy mix.

The future of geothermal energy in the UK

The future of geothermal energy in the UK is promising, but requires strategic development and support to unlock its full potential.

Overcoming challenges to deployment

While the UK's geothermal potential is significant, challenges remain, including the initial capital cost of deep drilling and the need for supportive policy and regulatory frameworks. However, as technology advances and the imperative for decarbonisation grows, these challenges are becoming more surmountable. Leveraging existing subsurface expertise from the oil and gas sector can also help reduce exploration risks.

Policy support and innovation

Government policy and support, including strategic documents like 'Future of the Subsurface: Geothermal Energy Generation in the UK', are crucial for accelerating geothermal development. Regulatory frameworks need to address drilling permits, resource ownership, and environmental impact assessments for deep geothermal projects. Continued innovation in drilling techniques and reservoir management will also drive down costs and expand viable locations.

Contributing to an abundant energy future

Geothermal energy, with its constant availability, contributes to a future where energy is so abundant it stops being a concern, aligning with Fuse Energy's vision of 'power to play with'. By highlighting the untapped potential of geothermal energy in the UK, this challenges the scarcity mindset and promotes the idea of abundant, clean energy resources. Fuse Energy supports the integration of diverse, reliable clean energy sources like geothermal into a modern, rebuilt energy system, ensuring a future where you have the power to play with.

Fuse Energy is a retail energy supplier for homes in Great Britain, committed to providing a modern, digitally-driven energy experience. While Fuse does not currently generate geothermal energy, we believe in a future powered by diverse, reliable clean energy sources. Switch to Fuse Energy today for 24/7 human customer support and smart tools to manage your home energy efficiently.