In the town of Ammanford, Carmarthenshire, Wales' first project utilising mine water as a source of renewable energy has been launched. A local company is now pumping water from the nearby Lindsay mine water treatment plant, where approximately 25 litres per second are treated before being safely discharged into natural watercourses. Thanks to geothermal energy and residual warmth stored in old mine shafts, the water can reach temperatures of up to 20°C.

The project uses heat exchangers submerged in a lagoon to transfer heat from the mine water, which maintains a stable temperature of 14 to 15°C. The system includes a MasterTherm Aquamaster 45 IP heat pump, which generates heat used to warm an industrial warehouse. The reservoir could alternatively heat up to ten family homes, and there is potential to scale the system to serve hundreds of households. The projected annual CO₂ savings currently amount to 17.5 tonnes.

Technology and benefits

The water treatment process removes approximately 28 kilograms of iron per day, helping to protect the Ffrwd Brook and River Loughor and contributing to healthier aquatic ecosystems. The integration of the heat pump system took only two weeks, adding both environmental and economic value to the site.

The project was made possible through collaboration between Thermal Earth Ltd and the Mining Remediation Authority, with funding from Innovate UK’s New Innovators in Net Zero Industry programme. According to representatives from both organisations, the project is an example of how innovation, cooperation and technical expertise can be turned into practical climate solutions.

Future potential

Wales, a country with a deep industrial and mining heritage, is pursuing a just transition to renewable energy through its national Heat Strategy. In 2024, the Welsh Government published a map of suitable sites for mine water heat use. Lindsay is one of those locations and now serves as a pilot model for further development.
As Gareth Farr of the Mining Remediation Authority said:
“We want to link our proud industrial past with a sustainable future.”

Similar projects are also growing in England – for example, Gateshead now uses mine water to heat more than 600 homes and businesses. The potential is significant in Wales as well – it is estimated that a quarter of the population lives in former coal mining areas.