Most people don’t immediately think of the UK when it comes to locations for geothermal hotspots. We tend to focus on areas such as Iceland with their hot sprints and where they’ve turned creating large scale geothermal power plants into something of an artform. Then there’s New Zealand where geothermal provides 13% of their heating.
The truth, however, could be a little more complicated, at least according to researchers at Durham University. Indeed, we might be sitting on top of heating source we never really considered. If what the scientist’s say is true, it may be entirely possible to extract geothermal power from our old coalmines.
Ground heat tends to increase the deeper you go. Around the UK we have vast networks of mining tunnels that have been left abandoned but could still be a useful asset when it comes to energy. For it to work, you need to have tunnels that are flooded with water in order to extract any heat. The good news is that most of the mining infrastructure is actually underwater and this could be very beneficial.
According to the Huffington Post, there’s a vast region of space under the ground that we could potentially use for district heating:
“Vast volumes (over 15 billion tonnes) of coal have been extracted from deep mines in the UK over the last century. To put this into context, if this extracted coal were spread over the UK land surface, this would result in a five cm deep layer of coal across the country.”
Researchers believe that the temperature difference in the water below ground could be used to provide heating for around 650,000 homes with the aid of heat pumps. The value of the heat pump is that it will take the slightly lower temperature of the underground water and boost it to more useful levels that can be used to provide hot water in homes and businesses.
The disadvantage is that, for this system to work, the users need to be close to the water source. There are hundreds of communities, however, that are situated right on top of abandoned and disused mines around the UK and these could certainly benefit from this kind of technology.
This isn’t a pie in the sky idea either – we already know it works. Creating district heating systems from old mines has been carried out successfully in areas such as Nova Scotia where the technology has been in place since the late 90s. A similar project was set up in 2008 in the Netherlands to provide district heating for residences and businesses over a 500,000 square metre site.
These successes abroad suggest that a similar approach in the UK could help provide local mining communities with decarbonised heating. We currently get around 70% of our heating from natural gas which is something that the Government is desperate to change. If we are to create a low carbon solution, it’s going to be necessary to draw on all available resources and try new ideas.
Investment in our old coal mines isn’t a complete solution but with other low carbon alternatives they could make a significant impact. And there’s something slightly ironic in using the remains of one of the dirtiest fuels on the planet to create new, clean energy.