Mine water technology extracts heat from floodwaters to power homes and it is hoped it could be used for millions of homes across the country
Britain’s coal fields once fuelled the industrial revolution, producing vast amounts of energy but also generating billions of tonnes of climate-warming CO2.
Now, decades after their closure, they are set to provide the UK with energy once again. Abandoned coal mines are estimated to lie under one in four UK properties and could be harnessed to fuel a heating revolution.
The new way to heat Britain’s homes would use floodwater from the old mines that has been naturally warmed by geothermal energy in the ground.
The ‘mine water heat technology’ extracts heat from the floodwater that has accumulated in abandoned mines, boosts it, and then uses it to heat homes.
And the success of the first largescale test of ‘mine water heat’ technology in Gateshead suggests it could play a crucial role in weaning the UK off gas boilers.
The mine water heating process extracts warm water from underground mines to be pumped into homes
This system effectively replaces standard household boilers with a giant, communal, heat pump by transferring the heat to a ‘clean loop’ of hot water that flows through a home’s pipes and radiators – no dirty mine water enters the home.
Millions of homes built on disused mines
Most of the warmth in the heat pump is transferred rather than generated, so they are typically three to five times more efficient than conventional heating technologies like gas boilers, which must heat the water from scratch.
As a result, customers of the Gateshead mine water heat project are being given a 5 per cent discount on their heating bills, compared with if the heat had been generated by a gas boiler.
The Gateshead project has been so successful it is being expanded from 350 to 640 homes – with plans to take it to 1,500 households in total in the next few years.
Analysis by Ordnance Survey, Britain’s mapping service, found that there are just over six million homes – about a quarter of total households – and more than 300,000 offices and businesses above abandoned coal mines, although not all will be suitable for development.
Many are located in the areas of greatest need, with nine out of 10 of our largest urban centres above areas of former coal mining activity.
The government said last month it was looking at ways to reduce the cost of electricity, which the heat pump is powered by, so the running costs could become even cheaper in the longer term.
Huge potential for renewable and low carbon heating
“Mine water heat has huge potential to provide renewable, secure and low-carbon heating for a wide range of building types in former coalfield areas,” Gareth Farr, head of heat and by-product innovation at the Mining Remediation Authority, told The i Paper.
“The Gateshead scheme shows that the technology is not only feasible but already delivering real-world benefits. With many communities located near disused coal mines, the potential for scalable, sustainable heating is significant.”
Construction of a mine water heating project has started in the town of Seaham, County Durham, which will see 750 homes heated using mine water.
And the first mine water heat project in Wales began operation in May, producing heat at an industrial site in the mining town of Ammanford.
The Minewater Heat Pump project in Gateshead. (Photo: Daniel Wetton/Mining Remediation Authority)
The Gateshead success has raised hopes that disused mines may one day be used to heat millions of homes across the UK.
This could significantly reduce bills and help the environment, as heat pumps produce far less CO2 than gas boilers, especially when the electricity that runs the heat pumps is generated from renewable sources such as wind or solar power.
The Mining Remediation Authority – formerly The Coal Authority – has set up a mine water heating research centre in Gateshead to learn more about the technology and “support its development as a reliable, low carbon heat source across the UK”.
It estimates there are about 2 trillion litres of water in old mine shafts in the UK, making mine water one of the UK’s largest underused clean energy sources.
Potential mine water hotspots
Newcastle, Sunderland and Stoke-on-Trent are seen as having particular potential for mine water heating, with large numbers of suitable mines and sizeable populations, according to a government report.
The research published this year and conducted for the Department of Energy Security and Net Zero found that Newcastle offered some of the best opportunities for mine heating systems, with large numbers of relatively shallow mines – of 300 metres deep or less – containing significant volumes of water.
It found that 85 per cent of the city was located on top of disused coal mines, most of which are suitable for mine water heating.
Meanwhile, 95 per cent of Sunderland is based above coal mines, of which just under half are suitable. Some 70 per cent of Stoke is also built on coal mines, two thirds of which are suitable.
In Wales it is estimated that about 50 per cent of the population live with in ex-coal mining areas across Wales. And 17 per cent of Welsh homes are in areas with good mine heat potential.
Other areas with good potential include Sheffield and Nottingham, with Bristol, Coventry, Leeds and Greater Manchester.
However, it is still unclear on what scale it will be cost-effective to use the technology as it depends on factors such the mines being heavily-excavated, their depth and being sufficiently flooded, as well as the size of the local population.
Professor Andy Mitchell, an expert in geochemistry from Aberystwyth University, said: “The coal fields of the UK drove the industrial revolution and over their lifetime accounted for the generation of about 10 billion tonnes of CO2, mostly through coal-based power generation.
“Now, if this technology turns out to be feasible on a large scale, the mines could help drive the push to a low-carbon energy future by replacing gas boilers in thousands, if not millions, of homes.”
A spokesperson for the Department for Energy Security and Net Zero, said: “We recognise the value of geothermal mine water as a possible energy source for heat networks in our clean energy superpower mission.”
“This is why we are supporting these types of schemes through the Green Heat Network Fund, which can provide cheap, clean and reliable heat to households.”