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Geothermal Energy

Durham University leads research into the potential for geothermal energy in the UK and abroad.

The UK’s geothermal resources are significant and could supply heat to the UK for over a century.

Our innovative research considers water in abandoned mines as a future low carbon heat source. We are working with the Coal Authority, Regional Local Enterprise Partnerships, Durham County Council, the BritGeothermal research partnership and Industry to explore this potential and develop demonstrators in the UK.

We are working with key stakeholders internationally, including governments and companies in the Oil and Gas sector, to promote the development of geothermal infrastructure and increase the use of Geothermal heat for industrial and domestic heating.

Our Director Professor Jon Gluyas is President of the new Geothermal Energy Advancement Association (GEAA) an initiative that brings together industry and academia to promote the role of geothermal energy in the energy transition globally.

Our research in Parliament

In 2019 Helen Goodman MP led a debate in Westminster on the use of abandoned mines for heat using evidence collected by Durham Energy Institute. This follows on from a study by Durham University on using mine water to heat homes in Spennymoor. This study found enough resource to heat a planned development of 200 homes.

“A source of clean, renewable energy under our feet is a very exciting prospect, and it’s all right here in the former coal mines beneath Spennymoor. The research carried out by Durham Energy Institute is very important in helping us better understand this resource and the ways we can best make use of it for a greener, more prosperous County Durham. This research was a key source for me when I led a parliamentary debate on Geothermal Energy, and I’m proud to work alongside the Institute promoting the benefits of this untapped energy source.”

Helen Goodman, former MP for Bishop Auckland.

Including Geothermal energy in regional energy strategy

DEI has been working with stakeholders from across North East England to ensure Geothermal energy from mine water is included in regional plans and strategies and considered for new developments. It is now incorporated as a key pillar in the North East Energy for Growth Strategy and Coal Authority has more geothermal projects in its pipeline for the region than any other region in the UK.

“DEI has been a central advocate for the geothermal potential in the region, and the opportunities this presents for our economy and to decarbonise heat, providing both the evidence base and enthusiasm to make sure this was a key theme in our Energy for Growth Strategy.”

Andrew Clark, Energy Programme Lead at North East Local Enterprise Partnership

Further information

What is Geothermal Energy?

Geothermal energy comes from heat produced at the Earth’s core. It is normally associated with volcanic regions e.g. Iceland or New Zealand.

Volcanoes are not essential for geothermal energy.

Away from volcanic regions, most countries can access geothermal albeit at lower temperatures. Temperature increases by 25-30°C with each km depth. This means that a well drilled to 2km would reach a temperature of 50-60°.

The key thing is finding water at depth that is essential for bringing heat to the surface heat to the surface. Durham University is researching the UK potential for geothermal energy to decarbonise heat.

Why is decarbonising heat important?

Decarbonising heat is a key component in limiting global warming and it’s role in climate change. Energy use in buildings represents 17.5% of global greenhouse gas emissions (https://ourworldindata.org/emissions-by-sector). Most of that energy is used for heating, and cooling. For countries like the UK, relying heavily on natural gas boilers for domestic heat, emissions associated with heating represent a significant portion of their carbon emissions, around a third for the UK’s (BEIS, 2018). It is therefore imperative to find alternative ways of heating our homes and buildings that do not release carbon dioxide into the atmosphere. This will enable us to achieve our decarbonisation ambitions and prevent the most disastrous effects of climate change on our societies and environment. 

Where is geothermal heat located?

Geothermal heat is heat within the earth. The word geothermal is composed of the Greek words geo (earth) and therme (heat). It can be found in many forms and virtually everywhere beneath our feet. The heat produced by the Earth is unevenly distributed and this is why in some places like Iceland and New Zealand, which are volcanically active, it can be found in the shallow surface and even on the surface itself as hot pools and geysers. In the UK we need to go deeper to reach such temperatures – usually 1000’s of meters. Heat extracted at those depths is sufficient to vaporise water into steam and used to produce electricity. 

Heat from abandoned mines

The deeper we go into the Earth the warmer it becomes. This is why even in flooded mines a few 10’s to 100’s of metres deep the temperature can reach up to 20 oC. This warm water can be pumped from abandoned mine workings and using heat pump technology at the surface, the heat it contains can be used to heat our homes. This mine water heat is the focus of the GEMS research group.

How much heat is down there?

With about 23,000 flooded mines across the UK, we can estimate the expected mass of water present in those mines, and its temperature. This warm water contains enough heat to heat tens of thousands of home for around a century. Therefore, we are undertaking research to provide insight and tools to industry, policy makers and the general public on this low-carbon resource which builds on the coal mining legacy of the UK.

Why aren’t there more geothermal systems?

The reason why we do not see more geothermal projects are multiple. The main reasons are:

  • This technology requires investment to build the plant or installation required to harvest the free geothermal resource. Currently these costs are often prohibitive. Yet, if a high quality heat source can be reached using existing infrastructure and wellbores (e.g. by repurposing oil and gas assets) then the technology can be considered competitive against hydrocarbon sources.
  • The regulatory landscape surrounding geothermal is currently ill developed. Hence, project developers often have to navigate a cumbersome set of regulatory rules which are sometimes not designed for geothermal technologies. The evolution of this regulatory landscape also casts doubt on the future costs associated with these projects which is perceived as risky by many investors.
  • The technology is extremely dependent on the geographic location of the resource and the demand. Indeed, when considering geothermal energy for heating applications, it is imperative that the source be close to the end user.

Yet, geothermal energy offers significant advantages compared to other forms of energy:

  • It is local and hence immune to geopolitical decisions
  • It has a high reliability factor (often more than 90%)
  • It is not variable, unlike wind and solar energy and 
  • Current technologies are sufficient to harvest geothermal energy