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Decarbonising heat production – coal mines and geothermal energy in the UK

Coal Miners, Midlands Colliery, England, UK, 1944 (source: Imperial War Museum, commons/ wikimedia)
Alexander Richter 4 Dec 2017

Exploring the opportunity of geothermal heating through abandoned and flooded coal mines in the UK, authors from Durham University conservatively estimate that around 650,000 homes could be heated by geothermal heating in the UK.

A recent article, by two professors from Durham University in the UK, describes on how the UK could use old coal mines to decarbonise the heat sector of the United Kingdom.

With fossil fuels dominating the production of electricity and heating, production of central heating is dominated by natural gas or around 70%. The UK has been a net importer of gas since 2004.

As discussed before, for the heating sector there are fewer low carbon alternatives than there are for electricity generation. Generally, solar hot water is a topic, but less so geothermal in the context of the UK.

Despite the UK, not having similar geothermal resources as New Zealand or Iceland, there are still geothermal fluids accessible of 100 degrees Celsius. This is hot enough to produce electricity and heating.

While drilling for this hot water has always risks attached, there are a large number of abandoned coal mines the the country, with many of their networks having been flooded at depths several hundred meters below the surface.

According to the authors, “one can be almost certain that the water flow necessary for deep geothermal wells can be found in those flooded underground voices.” This makes it much easier and less risky to tap into geothermal resources, given that the water exists. Given the depths of those mines, water could be sufficiently warm for heating applications, or if not at least be used for geothermal heat pumps that than create useful temperatures of 40-50°C.

Describing the successful implementation of similar projects, e.g. in Nova Scotia/ Canada the authors believe in the opportunity, stating that by conservative estimates around 650,000 homes in Britain could be heated this way.

The end with the “delightful irony that the legacy of the dirtiest of fuels, coal, now has the potential to deliver a low carbon energy future.”

Source: Huffington Post