​A business in Carmarthenshire has become the first in Wales to use warm water from a disused coal mine as a renewable source of heating.

Located near Ammanford, the system draws flood water from the former Lindsay colliery, which is treated at a nearby mine water treatment facility. The water, naturally heated underground to around 14°C to 15°C, is channelled into a ground source heat pump to provide year-round heating for a warehouse on site.

The 35 kilowatt system has been specially designed for the building but is scalable and capable of supporting larger developments. Its current output is sufficient to heat up to ten new-build homes, highlighting the potential for mine water heat as a sustainable solution for residential and commercial properties.

The project received funding from Innovate UK and is seen as a key step forward in harnessing Wales' industrial past to support a greener future. With around a quarter of the Welsh population living on former coalfields, opportunities for similar schemes are widespread.

A map published by the Welsh government last year identified viable locations across the country for mine water heating projects. Work is already underway to support the development of further schemes across south and north-east Wales.

In England, mine water heating is already in operation, with a scheme in Gateshead serving over 600 homes and community buildings. The success of that initiative has helped inspire efforts to replicate the model in Wales.

The Welsh government said mine water heat could play a significant role in achieving net zero and highlighted the potential for funding through local energy initiatives. A new £10 million capital fund from Ynni Cymru is also available to support smart local energy systems and encourage further innovation across Wales.