A district heat network that draws warmth from flooded coal mines is now fully operational at Seaham Garden Village in County Durham. The Mining Remediation Authority said on 6 October 2026 that the new energy centre had completed commissioning and will supply heat and hot water to around 750 affordable homes.
The heat comes from the authority’s Dawdon mine water treatment scheme, which already pumps water out of the old workings to protect local drinking water supplies. That water is now doing a second job: heat exchangers and a heat pump take the warmth from it, raise the temperature and send it round a district network to the homes.
Who is involved and what it saves
The project is a partnership between the Mining Remediation Authority, housing association Karbon Homes, Esh Construction, Vital Energi and Durham County Council. It received money from the government’s Heat Networks Investment Project, and Vital Energi will run it as the energy services company that supplies residents.
The authority estimates the scheme will avoid about 2,600 tonnes of carbon dioxide a year, or roughly 64,000 tonnes over 25 years. Residents have been moving in since the start of 2026. The 750 homes are part of a wider garden village of 1,500 homes, and the authority says the network has the capacity to expand to serve all of them in future.
Why mine water matters
Water in abandoned coal workings is warmed by the surrounding rock and stays at a steady temperature all year. According to the authority, it is typically 10 to 20°C and can reach 40°C at depths of around 1km. That is not warm enough to heat homes on its own, which is why a heat pump is used to boost it, but the source does not dip in winter the way outdoor air does.
The potential is large. An estimated quarter of homes and businesses in Great Britain sit above former coal mines, and the authority operates more than 80 mine water treatment schemes, many of which it says could be adapted to provide heat. Seaham follows the Gateshead network, which went live in March 2023 and remains the largest mine water heat scheme in Great Britain, and a smaller commercial scheme at Lindsay in Carmarthenshire.
What it means for households
For residents at Seaham, heating and hot water come from a shared network supplied by Vital Energi rather than from a boiler in each home. The partners present the scheme as a way to shield families from swings in fossil fuel prices, because the heat source is local and does not depend on imported gas.
More broadly, the project shows how low-temperature geothermal heat can be put to use in Britain by reusing infrastructure that already has to be kept running for environmental reasons. Durham County Council has said it is looking at where else the approach might work. For more on the science, see our geothermal energy guide, and for a very different approach to the same resource, read about the UK’s first geothermal power plant in Cornwall.