West of England coalmines to be mapped for renewable energy potential

Regional mayor Dan Norris launches project to explore potential for former mines to produce low-carbon heat

When Bryn Hawkins worked in coalmines through the 1960s and early 1970s he says few understood the impact the burning of fossil fuels would have on the planet.

Now, public officials are hoping disused mines that provided millions of tonnes of fossil fuels could be used as a potential source of renewable energy across the country.

It has already been a success in Gateshead, where the council-owned Gateshead Energy Company is using warm water from the extensive network of old mine workings 150 metres below the town to supply heat and hot water.

Other authorities are catching on to the potential with the metro mayor for the west of England, Dan Norris, betting £1.5m that some of the 100-plus mines in Somerset and South Gloucestershire will be able to provide a renewable source of heat in the region.

Speaking at the launch of a mapping study in the former mining town of Radstock, Somerset, Hawkins, 82, is buoyed up by the prospect of the mines that provided a livelihood for him and his family being repurposed for the benefit of the environment.

“It’s wonderful,” he says. “In my lifetime, the concerns about the environment have come up relatively recently. We didn’t think anything of the smoke going out of the chimneys. But now there’s more interest, more attention – and I understand it a little bit more.”

When mines were up and running they were pumped dry so miners could access the coal. When they were closed, the pumps were turned off and the mines were flooded again.

The water is heated by geothermal energy, the heat from the Earth’s core, and in some places can reach temperatures of about 20C.

Dan Mallin Martin, a hydrogeologist with the Coal Authority, the public body responsible for managing the effects of past coalmining, says this naturally heated water can be brought up through shafts or boreholes and passed through a heat exchanger – extracting the heat from the water.

“Typically we can take out around five to 8C, which doesn’t sound like a lot, but if you pass that to a heat pump, which is effectively a fridge in reverse, it boosts the temperature to something we can use – something like 60 or 70 degrees centigrade – that can go into people’s homes, people’s businesses, into hospitals, heat networks, many different end users.

“That’s a great way to make use of that and they can be really efficient. And really low carbon.”

The process has no net water consumption – that is it does not take out more than it uses – as the mine water is put back into the flooded mines and recycled.

“The transition to heat pumps as an energy source is very important and that’s one of our options for decarbonising our heating requirements across the UK,” Mallin Martin said. “With heat pumps, ground source options and mine water, we can feed into that decarbonisation, especially if we couple it with green electricity like solar panels and wind.”

The Gateshead Energy Company powers its centralised heat pump with a solar farm and estimates to be saving about 1,800 tonnes of CO₂ a year.

There are international examples of this tech being used successfully. The mine water project in Heerlen, in the Netherlands, is described as the “poster child” for the innovation.

“There’s a real green incentive to make the most of this and it certainly supports the levelling up agenda in the communities on the coalfield by delivering secure, local, low-carbon heat,” said Mallin Martin.

Like a lot of nascent energy solutions, political will is also key. Norris, who has been mayor in the west of England since 2021 and is from a mining family, has committed £1.5m to a mapping study to establish the extent of the mine network in Somerset and South Gloucestershire. Once this is established, the authority will zone in on the most viable locations for further tests.

“The synergy is fantastic that mines that contributed to CO₂ emissions could now hold the key to clean, green energy,” Norris said. “Heat from mines has national, and possibly global, implications too.

“If the cost of living crisis tells us anything, it tells us that the cost of energy is critical, not just to the poorest in our communities, but actually everybody and businesses as well. So we have got to make the cost of energy much cheaper.

“And I believe that this is an environmentally important way of producing that energy, but also a cost-effective way of producing energy that can heat up our economy and help cool down our planet and I’m excited about that.”

Cover photo: Miners in Kilmersdon colliery in Somerset in 1962. Photograph: Coal Authority