The Mining Remediation Authority has announced that Wales' first commercial mine water heat scheme using previously untapped heat from a mine water treatment scheme is live in Ammanford and providing low-carbon heat to a nearby industrial site.

With its industrial heritage and coal mining past, Wales has recognised the potential of mine water heat through its Heat Strategy for Wales, as a viable option to support the transition to renewables.

The Mining Remediation Authority (MRA) identified an opportunity for low-carbon heat recovery at its Lindsay treatment scheme near Ammanford, Carmarthenshire, as part of its work to map areas of Wales most suited for mine water heat schemes, which was commissioned by the Welsh Government.

The MRA operates more than 80 treatment schemes across Great Britain and at Lindsay it pumps and treats an average of 25 litres of mine water per second. The process removes approximately 28 kilograms of iron each day, preventing it from entering local watercourses, protecting the Ffrwd Brook, which flows into the River Loughor, safeguarding aquatic ecosystems and contributing to cleaner, healthier rivers in the region.

Now, for the first time in Wales, the heat from mine water is being harnessed to provide secure, low-carbon heating at an industrial site.

The mine water is naturally warm due to geothermal energy from the earth’s crust and heat retained from its time circulating through underground rock layers and former coal mines.

Working in collaboration with local business Thermal Earth Ltd, the renewable heat project secured funding through Innovate UK’s New Innovators in Net Zero Industry, South West Wales initiative.

Constructed in just two weeks, the innovative project utilises heat exchangers submerged in one of the settlement ponds at the Lindsay scheme to recover heat from mine water, which is then transferred to a nearby industrial unit to supply low-carbon heating and hot water, and is predicted to save 17.5 tonnes of CO2 per year.

Photo: Heat exchangers being installed into the treatment lagoons

Andrew Simpson, head of Innovation, By-Products and Services at the Mining Remediation Authority, said:

“It’s been incredibly rewarding to see this forward-thinking project, transforming part of our mining legacy into a source of clean, renewable heat.

“This scheme demonstrates how Wales’ industrial heritage can be repurposed to support a low-carbon future.

“By unlocking the potential of mine water heat, we’re not only reducing emissions but also creating a blueprint for sustainable energy that can be replicated across the country.

“We hope this success inspires others to explore the untapped potential of mine water heat as a reliable, renewable energy source.”

Photo: Heat pump system installed at Thermal Earth

Nick Salini, managing director of Thermal Earth Ltd, added:

“Completion of this demonstration project marks a monumental step forward in sustainable energy innovation.

“By harnessing the untapped thermal energy from mine water, we’re not only pioneering the first commercial use of heat from a mine water treatment scheme in Wales but also redefining what’s possible for renewable heating.”

The Lindsay scheme has been successfully treating mine water since 2003 - the MRA said pioneering the concept of adding heat recovery features to treatment sites is part of its wider geothermal energy research.

The new development follows the success of the privately-funded project at Lanchester Wines warehouses, which has been successfully using mine water to provide low-carbon space heating since 2018, and the Gateshead scheme, the UK’s first large-scale mine water heat network, which began providing heat to homes and businesses in March 2023.