Could disused coal mines soon be heating homes and businesses in Wales?

Taff’s Well is Wales’ only thermal spring. The natural flow of warm water is providing heating to the nearby park pavilion and the local primary school.

“In simple terms, instead of it (water) being discharged into the River Taff, we divert it to heat exchangers to capture that heat and then put it back on its way to the River Taff", said John Arroyo, Energy and Carbon Reduction Manager for Rhondda Cynon Taff Council.

“It was technically pipes in the ground to divert it to a heat exchanger and then from that heat exchanger, that usable heat then would heat the primary school and the pavilion and that’s what we’ve managed to achieve.”

Taff’s Well thermal spring isn’t the only source of natural warm water in Wales. Mines played a crucial part in firing up the industrial revolution but when the pumps that kept them dry were switched off, they filled up with water.

The Welsh Government has announced a £450,000 project to explore whether water from disused mines could be used to heat up homes and businesses across Wales.

“The mine water is of a similar sort of temperature to the thermal spring", John added.

"The ambition then is to take that heat pump technology and see how we can retrospectively install it into an existing building."

When asked how big of a deal this would be if the project was a success, he said: “To decarbonise Rhondda Cynon Taff would be quite a big deal. It’s probably one of the biggest challenges we’ve faced and these are the type of solutions that we need to address.

“It might seem ambitious for some but this is where it starts”

Around  40% of the energy used in Wales provides heat to homes, businesses and our industry.

Most of this heat comes from gas, but by 2025, there will be no gas connections in new build homes in Wales to support decarbonisation efforts.

Mine water is a low carbon, sustainable heat source, which could compete with public supply gas prices and deliver carbon savings of up to 75% compared to gas heating.

The Coal Authority is going to be working with the Welsh Government to investigate whether this project could potentially work. 

But it isn’t the first time this concept has been looked at. This idea was explored by Bridgend Council back in 2018. They came to the conclusion that the project was too expensive and more research was needed.

The Welsh Government had awarded the project £6.5 million in EU funds.

But the Coal Authority hopes it will be different this time.

Gareth Farr, Head of heat and by-product innovation said: "Since that time, there’s been a lot of progress in the north east of England and there’s been a lot of learning done where we’ve already been part of a scheme that’s gone from concept to delivery in the space of three years. 

“We hope that exemplar schemes like the Gateshead heat network which will provide heat to up to a thousand homes this winter will be the springboard for replicating this in Wales.”  

 A Welsh Government spokesperson said: "The initial mapping work will look across Wales to identify areas where projects are more likely to succeed versus those which will be more challenging.

"We recognise that it is rarely possible to eliminate all project risks, but our approach gives us the ability to identify and address the risks without incurring unacceptable project costs."