Flooded, disused coal mines could change how our homes are heated

LONDON — The ramifications of the Industrial Revolution, which had its roots in 18^th-century Britain, were huge.

Britain’s abundance of coal — as well as the ease with which it could be accessed — was a crucial ingredient in this historical turning point, powering the steam engines which helped drive society’s transformation.

But things have changed. The number of operational coal mines there has plunged, and last June, authorities announced Britain would stop using coal to generate electricity from October 2024, a year earlier than the original target of 2025.

Even though most mines in the U.K. have closed, their centuries-old story isn’t necessarily over. In Scotland, work is underway to look at how the water that has flooded old, disused mines can be used to provide decarbonized heating to buildings.    

Conducting this research is a facility known as the Glasgow Geoenergy Observatory, which is run by the British Geological Survey. A dozen boreholes have been drilled, with the majority in Rutherglen, a town southeast of Glasgow.

According to those behind the project, both Glasgow and Rutherglen were home to some of the busiest coal mines in Scotland. After their closure, natural floods filled them with water of about 12 degrees Celsius.

Mike Stephenson, who was until recently executive chief scientist for decarbonization at the British Geological Survey, told CNBC that the project was about “doing research on the heat in coal mines and also, to some extent, whether you can store heat in old coal mines.”

Stephenson said that at the site where the work is taking place, the team was “experimenting with … how fast water flows amongst these mines, how warm the water is, how … fast, if you take warm water out, does the water replenish — so how fast does the warmth come back.”

“It is a research site, not a demonstration,” he said. Research was being undertaken “to try and understand what are the limits to the amount of heat, how much heat there is.”

“All those things will be a set of scientific findings and equations and models,” he added. He said this would provide valuable information to both companies and local authorities interested in the idea.

“It will help them decide where to do it, how close you drill the holes together, how deep you drill them, how you design them to make it as efficient as possible.”

The project has made progress over the last 12 months or so. In the summer of 2021, it was announced that pumping tests had been completed and samples collected from 10 of the site’s boreholes.

“The latest data show that the boreholes of the Glasgow Observatory are well-connected to the flooded mine workings,” Alan MacDonald, a hydrogeologist with the British Geological Survey, said at the time.

Mine water between 50 and 90 meters under Glasgow measures between 11…