Posted: Thu 17th Feb 2022

Seminar set to explain potential of heat stored in abandoned coal mines for people living in or visiting the wrexham area
This article is old - Published: Thursday, Feb 17th, 2022

According to the Coal Authority, one quarter of the UK’s homes and businesses are above abandoned coal mines. The mines are warmed by natural geothermal processes and where the mines are flooded, these are now being developed as a source of low carbon energy to heat homes and businesses.

The method is theoretically straightforward, a borehole pumps the naturally heated water to the surface and then a heat pump or exchanger creates useful heat from it, and the water is then returned back down to the mine workings.

Mine water gets warmer the deeper it is, following a ‘geothermal gradient’. Temperatures range from 10 – 20°C however they can reach 40°C at depths of around 1km. Mine water can be abstracted from boreholes, shafts or adits.

They explain, “Water within the mines is warmed by natural processes and can, if sustainably managed, provide a continuous supply of heat. Mine water temperatures are not affected by seasonal variations and, subject to the right support, mine water can provide renewable, secure, low carbon heating for buildings in coalfield areas.”

The Coal Authority is arranging a free webinar next month on the topic, explaining, “Decarbonisation of heating and hot water is one of the largest challenges facing the energy transition as we step up to the NetZero challenge. One solution is to use mine water from disused coal mines to recover low carbon heat that can be distributed via heat networks to homes and businesses using existing technology.”

“Large areas of Great Britain are underlain by disused coal mines, and these areas could benefit from low carbon mine water heat, supporting green jobs and improving energy security. Join specialists from the Coal Authority to learn more about how this technology works and where it can be applied using We will describe the theory behind this technology and also illustrate real life case studies from Great Britain, where work is underway to construct district scale mine water heat networks”.

The top image is via a  mapping tool – use the drop down menu at the top right hand side of the screen to select Temperature Maps. The tool is aimed at developers, planners and researchers to ‘identify opportunities to investigate the use of mine water as a sustainable heat source’.

BGS geoscientist Gareth Farr, who led the project, said: “This has been a very exciting piece of work. It’s the first time we have been able to visualise the temperature of Britain’s coalfields. We have found records of heat temperatures going back more than 100 years and compared them to temperatures in the mines now, and found them to be quite similar. This is a clear indication that geothermal processes that create this heat will be here for a long time to come.

“Combined with other layers of data, the maps provide an important groundwork for developers, local authorities and scientists to explore new mine water heating schemes, and we are hopeful they will be of value to inform policy decision making.”

Locally the below map has been kindly created by data expert John Murray, Visiting Professor in the Geographic Data Science Lab at University of Liverpool, showing abandoned mines and shafts on 1:50000 scale in the area.

There is no indication that any are under consideration for such schemes, however does show possible reach and potential if the concept gains traction and is rolled out.

Produced using Ordnance Survey & The Coal Authority data “© Crown Copyright 2022

Produced using Ordnance Survey & The Coal Authority data “© Crown Copyright 2022


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