This story was originally published by Reasons to be Cheerful
9 min read
In the town of Gateshead in North East England, coal mining runs thick in the blood. Up to the final coup de grâce delivered by Margaret Thatcher’s coal purge in the 1980s, Gateshead had been tapping its dark subterranean seams as far back as 1344, when packhorses conveyed “sea coal” from pits pockmarking County Durham’s rolling countryside to gull-swarmed keels on the south bank of the River Tyne.
But although Gateshead’s coal industry no longer exists, its heritage lives on. Indeed, at a Lanchester Wines warehouse in east Gateshead, Chris Smith likes to think of himself as following his grandfather underground. His granddad was a miner, but Smith, Lanchester’s energy and renewables manager, now helps pull a different kind of energy from the same earth: heat from warm water flooding the town’s old coal workings. “I’m here almost doing the same, just in a different way,” he says. “Still kinda going back down the mines … and extracting heat and energy.” He pauses, then smiles at the symmetry of it. “I do find it quite poetic.”
That poetry now runs beneath much of Gateshead. In March 2023, a council-backed mine water heat network went live, using a six-megawatt water-source heat pump to draw warmth from flooded mine workings roughly 150 meters below the town. The heat is distributed through more than five kilometers of pipe to about 350 homes, plus Gateshead College, the Baltic Centre for Contemporary Art and other buildings. The U.K. government says the initiative will save 72,000 metric tons of carbon dioxide over 40 years.
The basic engineering is surprisingly simple. Dan Mallin Martin, a hydrogeologist at the Mining Remediation Authority (MRA), a non-departmental public body responsible for managing the environmental legacy of historical coal and metal mining across the U.K., says the old workings in Gateshead are naturally filled with water, geothermally warmed at about 15 degrees Celsius. That water is pumped up from around 150 meters down, passed through a heat exchanger and then into a large industrial heat pump, which boosts the temperature to roughly 80 degrees Celsius for the district network. The mine water returns underground around five degrees cooler, where it gradually absorbs heat from the surrounding rock before being pumped up again. “You can take something mildly warm and turn it into something very usable for heating,” explains Mallin Martin.
He describes the workings beneath Gateshead as a “massive interconnected network” of old mines. And there already are multiple projects tapping into it. Lanchester Wines was the first private business in Great Britain to use mine water heat. Its two open-loop systems (which pump mine water to the surface and return it underground, unlike closed-loop systems that circulate a separate fluid through sealed pipes), introduced in 2017 at one of the company’s warehouses and another in 2019, now have a combined capacity of four megawatts and heat 33,445 square meters of warehouse space. And the MRA, through its Living Lab dataset, monitors water levels, chemistry, temperature and pressure around three nearby mine water heating systems, creating an unusually public evidence base for future operators.
There is now more than one way to see the network’s success. At the broad level, the government can point to a live, city-scale heat system that has been operating for more than three years and is one of Europe’s largest. According to Gateshead Council, the network has recently been extended to an additional 270 new-build homes and a separate retrofit pilot has connected a further 16 existing homes, plus an assisted living facility and a church, without replacing the homes’ existing radiators.
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At the business scale, Lanchester Wines says the two mine water systems have cut the warehouses’ carbon footprint by 80 percent, from 3,600 metric tons to 750 metric tons over several heating seasons. Smith says the warehouses’ coefficient of performance is typically around five or six, meaning one unit of electricity can deliver five or six units of heat. “That’s where you benefit,” he explains.
Then there is the household test. One local resident, who asked to remain anonymous, has lived in the same Gateshead home for the past 52 years, and was converted to the council’s mine water heat network two years ago. He was told the new system would be cheaper, but little else: “They put the pipes in, and that was it. I didn’t have much choice.” But the practical result, he says, has been good. His bills are lower; he pays £100 (about $135 U.S.) a month into his energy account and has built up a credit balance of about £600 — meaning he has paid £600 more than the energy he has used. The service itself feels ordinary in the best possible way. “It works exactly how you would want,” he says.
Michael Smith, an associate professor of psychology at Northumbria University who has researched local attitudes to the mine water heating, says that ordinariness is part of the point. One resident in his research summed it up plainly: “Well, I turn the hot tap on, and hot water comes out.” But he found three broader messages that resonated: cheaper bills, lower local emissions and pride in reusing mining infrastructure. The bills matter most, he says. The heritage story helps people make sense of the technology and can turn it into something more than a utility project. “Reuse” was a word people returned to repeatedly.
Still, this is not a frictionless template. Gateshead’s drilling campaign hit the limits of Britain’s — typically hand-drawn — mining records. Mallin Martin recalls that, of 12 boreholes drilled, only four were successful, partly because older workings were poorly mapped. His lesson is blunt: Build in contingency and assume you may not get it right the first time. Lanchester Wines’s first site had similar problems. Smith says the company drilled around eight boreholes to get roughly two useful ones. Acidic mine water also damaged the steel heat-exchanger plates.
There are softer limits, too. Publicly available information is strong on the initiative’s ambitions, but much weaker on how it is performing in practice and what it costs to run. Community engagement also appears uneven. The resident who reported lower bills was satisfied, but was told little of where the heat came from. Smith, at Northumbria, warns that former coalfield communities are often “used to having things done to them or for them — but not with them.” If mine water heat is going to stand for a just transition, he argues, residents need real influence from the start — over the disruption caused by the construction work, pricing and who ultimately benefits.
That may be the real lesson of Gateshead. The mines matter, but they alone are not the solution. What makes a system work is a dense pocket of heat demand, a network above ground, an institution willing to take drilling risk, and a community that sees some tangible gain in return.
The opportunity extends well beyond Gateshead. Britain has around 23,000 abandoned deep coal mines, with an estimated quarter of its homes and businesses located above former coal workings. That 2021 sector assessment identified 42 prospective British projects that, if developed, could support nearly 4,500 direct jobs, create a further 9,000 to 11,000 supply chain roles and avoid about 90,000 metric tons of carbon dioxide. But the strongest candidates are not necessarily the places with the warmest water. They are dense towns where flooded, sufficiently deep and well-connected workings sit close to housing, hospitals, campuses or industrial users — preferably alongside an existing heat network, shaft or mine water pumping station.
Worldwide, a 2025 review identified 51 mine water energy systems currently operating, providing around 85 megawatts of heating and 20 megawatts of cooling, with another 61 projects planned or under study. Most are in Germany, Britain and the U.S., where long mining histories coincide with hefty heating demand. Early success stories include Springhill, Canada, operating since 1988, and Heerlen in the Netherlands, whose former mines now underpin a district heating and cooling network. Appalachia offers another vast prospective market: Millions of Americans live within a mile of an abandoned coal mine, and the U.S. Department of Energy is testing whether billions of gallons of water beneath former mines in southwest Virginia could cool data centers.
China, however, may offer the greatest scale: High-temperature mines span 13 of its 26 main coal-producing provinces, with almost three-quarters of the estimated resource in northern China. Active mines can also capture heat from water they already pump to the surface. As Mallin Martin puts it: “Anywhere where there are former mine workings is a good start. It’s just about marrying up that technical feasibility with the demand and appetite of a developer.”
But turning that buried legacy into useful public infrastructure will depend as much on governance and trust as geology. The Gateshead resident who chose to remain anonymous did not talk like an energy strategist. He spoke like a man whose heating worked and whose bills have eased. Asked whether another former mining community should try the same thing, he did not hesitate. “Yes, I would, aye,” he said, with a thick Geordie twang. “They can only benefit from it.”
The post Transforming Britain’s Old Coalfields Into Clean Energy Sources appeared first on Reasons to be Cheerful.
