How geothermal energy can boost Cumbria’s economy

It’s time to unleash the heat beneath our feet to power our businesses and homes sustainably, writes Mark Griffiths of Hydrock, now Stantec.

Geothermal energy presents an untapped market for Cumbria that is in line with the county’s ambitions to be a green energy superpower and a leader in the mission to combat climate change.

Cumbria’s target is to reach net zero emissions by 2037, well ahead of the national goal, with the Zero Carbon Cumbria Partnership at the heart of driving plans forward.

According to the Durham Energy Institute, there is theoretically enough deep geothermal energy to heat every home in the UK for at least 100 years. This seems too good to be true, but even conservative estimates suggest deep geothermal could provide 15,000 GWh of heat for the UK by 2050. It would help diversify our energy mix and reduce the need for gas — maybe even to the point where the North Sea meets our demand for fossil fuel, providing long-term energy security for generations.

Supported by the likes of Friends of the Earth and the United Nations, geothermal energy is widely regarded as an environmentally friendly source of heat and, in the right location, electricity. This is because of its lower greenhouse gas emissions compared to carbon-based sources, minimal air pollution, efficient energy conversion, and lower water use compared with most conventional technologies.

Deep geothermal is therefore an opportunity that more than deserves attention, and we should be doing everything we can to unlock it.

How deep geothermal works

In the UK, deep geothermal energy typically relates to drilling one or more boreholes to depths greater than 500 metres or where temperatures exceed 50°C to make direct use of heat in the ground. The heat is then transmitted through water, which is either sourced from the ground directly (within deep aquifers) or artificially introduced from the surface via a borehole and heated-up through contact with hot rock.

The deeper you go, the hotter it gets, providing more energy. But how deep depends on the local geology and the temperature you need for your project.

Shallower depths are good for warming your home, but for industrial uses or electricity generation, you need to drill deeper.

Areas most suited for conventional deep geothermal are mainly concentrated in the North of England, the Midlands and the South West, as deployed at United Downs, Redruth, and at the Eden Project, due to their geological conditions.

Incidentally, a lot of the areas most suited are where investment is most needed to level up. In the North West, that’s around places like Carlisle and Crewe. But, with the exception of projects in Cornwall, there’s been little uptake of deep geothermal in the UK since the government funded exploration work in the 1980s.

So why aren’t we jumping on a consistent ‘always on’ source of renewable energy? It sounds like a no-brainer. Most cited reasons are the high capital cost, disjointed policy, and geological uncertainty.

This is despite over 2,500 boreholes being drilled onshore in the UK by oil and gas companies to depths of at least 500 metres in the past 50 years, as well as 1000s of kilometres of geophysical data being freely available to view. We have the data, capability, and skills in the UK to make it work.

However, achieving large-scale decarbonisation of heat through deep geothermal, as with any clean technology, requires confidence for investors and developers, which, clearly, is what we’re missing.

Long-term financial incentive would encourage private sector investment to exploit and develop the UK’s geothermal sector. This may be achieved through feed-in tariff or a change to the Contracts for Difference structure, which has been instrumental in stimulating the development of offshore wind and solar energy. To speed things up, we also need clear and supportive planning rules, along with a faster and more focused system for approving geothermal projects.

For now, extracting lower temperature geothermal heat for use in heat networks represents the path of least resistance.

District heating networks

Heating our homes and buildings is a major hurdle on the road to net zero in the UK, and we haven’t quite figured out how to tackle it on a large scale yet.

The good news is that other parts of Europe are showing us the way. In Paris, over a quarter-of-a-million homes are already heated with geothermal energy, delivered through a network of 50 heating systems. And Germany is investing heavily, aiming for 100 geothermal projects by 2030.

While our own government has been slower off the mark, we’re now seeing a focus on heating networks in the UK. Enabled by the Energy Act 2023, heat network zoning will designate areas of England where heat networks are expected to provide the lowest-cost, low-carbon heating. The government is currently evaluating responses to the consultation process, with the final regulations expected later this year.

In anticipation of the likely regulatory direction of travel, local authorities have already started exploring their options, bringing in specialist advice to help them identify potential zones to drive heat network development.

Will geothermal really take-off in Cumbria?

There’s the argument that the rural nature of the area means there’s far less heat demand from communities than in a large city centre. Whilst broadly true, this dial will shift as the region looks to achieve its growth ambitions by positioning itself as a ‘manufacturing powerhouse’ and exploiting opportunities associated with clean energy and the green economy. As a result of the region’s regeneration, new jobs would likely mean a growth in population, requiring new infrastructure and housing, most of which will require heat.

Current, successful Cornish deep geothermal projects target granite rock. Similarly, large parts of Cumbria are situated above granite and while initial data suggests the granite in Cumbria is cooler than in Cornwall, it could be an untapped resource for clean and sustainable energy.

In addition, there are former mine workings in the North and shallow aquifers along the coast which present geothermal opportunities.

With a history of energy and innovation behind it, Cumbria could well be the regional geothermal champion to drive us forward.

• Mark Griffiths is associate hydrogeologist at Hydrock now Stantec
• Griffiths spoke at the recent Place North West Cumbria Development Update – read the summary