UK switches on first deep geothermal energy site in four decades

After nearly forty years of dormancy, the United Kingdom has finally embarked on a new chapter in deep geothermal energy, unlocking a reliable, sustainable, and almost infinite source of heat. On Monday, the long-awaited initiation of the Eden Project’s deep geothermal well took place, a venture that experts believe could invigorate the geothermal energy sector, despite the high expenses associated with it.  

Nestled within the beautiful landscapes of Cornwall, the Eden Project is the host of the country's first geothermal well that delves nearly 5km into the Earth's crust. This significant depth enables access to groundwater that can reach a scorching 200°C. This heated water is harnessed to warm the adjacent greenhouses and the impressive, enclosed rainforest biomes, which are part of the Eden Project. 

Maintaining a rainforest biome is no small feat, says Eden Geothermal’s CEO, Gus Grand. The implementation of this geothermal system is projected to curtail Eden Project’s energy costs by around 40%. 

This innovative venture arrives amidst a surge of interest in the potential of geothermal energy within the UK, notably from the National Health Service. The NHS is contemplating employing geothermal heating for several hospitals to help achieve its net-zero objectives. 

A governmental white paper, detailing an in-depth analysis of deep geothermal energy's potential and providing policy recommendations, is slated for release in the following weeks. 

Deep geothermal energy exploits the Earth's core heat by accessing hot water reservoirs underground. This type of power is not only dependable but also generates minimal emissions, making it a sustainable energy solution. The 1970s energy crisis sparked initial interest in geothermal projects in the UK, yet specific policy support for such projects has been missing. 

Distinguishing itself from shallow geothermal ventures that make up most of the existing geothermal projects in the UK, deep wells surpassing 500m in depth can access extremely hot water, which can be utilised for heating and electricity generation. 

Upon its commencement, the Eden geothermal well stands as the sole operational deep geothermal well in the UK. "It will draw significant attention, and justifiably so," comments Professor Jon Gluyas, the executive director of the Durham Energy Institute. "It will showcase that deep geothermal can supply low-carbon heat to consumers throughout the region." 

Further initiatives in the pipeline include the United Downs Deep Geothermal Power Project in Cornwall. This project is set to generate both power and heat and has completed drilling two deep wells, with another plant being planned. 

The UK’s inaugural deep geothermal energy system was launched in Southampton in 1986 but is currently under repair. One of the recurring hurdles for geothermal energy in the UK is the expensive drilling process. Unlike Iceland, which is located near tectonic plate boundaries, the UK's heat sources are buried deeper beneath the Earth’s surface, increasing drilling costs. 

At Eden Geothermal, CEO Grand acknowledges the challenges they encountered during drilling, noting its high costs. "We had to drill through granite, which is extremely tough and costly. Moreover, we were carrying out the process amidst the Covid pandemic, which only added to the expenses," she explained. "This is essentially a demonstration — a research project. A commercial project would not have been executed this way." 

Partially funded by the European Regional Development Fund and Cornwall County Council, the well incurred construction costs of around £24 million and the current system is expected to produce around 1.4MW of energy. 

Grid connectivity duration is another challenge these projects face. It’s becoming a significant issue for many renewable projects across Europe, with Grand lamenting, "We would love to convert it into electricity, but getting a grid connection is a nightmare - mine is scheduled for December 2036." 

Geothermal energy, however, could bring more immediate benefits in the heating systems sector, which typically doesn't require the same depth or expenditure for wells as required for electricity production. 

The geothermal energy produced will be utilized to power the Eden Project’s new nursery, Growing Point, along with its biomes and offices. This groundbreaking geothermal project began operations on Monday, heralding a new era in deep geothermal energy for the UK, despite the relative high costs. 

The excitement around this venture isn’t just confined to its potential for energy production but also its potential to breathe new life into the argument for a serious adoption of deep geothermal energy as part of the UK's energy mix. 

The resurgence of deep geothermal energy in the UK, initiated by the Eden Project, has rekindled hopes for its widespread adoption. As Tim Smit, the co-founder of the Eden Project, puts it: "Geothermal is the sleeping giant of renewables: lying not under our noses, but literally under our feet. The Netherlands’ geothermal industry started with heating for greenhouses, and they are now aiming for it to contribute to a quarter of all their heating by 2050." 

It's worth noting that geothermal technologies currently contribute to less than 0.3% of the UK's heat demand, a figure that pales in comparison with other European countries. With the right policy support, the UK has a massive opportunity to benefit from this resource that can substantially contribute to decarbonising and improving the security of the country's electricity and heat systems.