Coal mines transformed society. Now their flooded remains could heat the homes of the future

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The ramifications of the Industrial Revolution, which had its roots in 18th century Britain, were enormous.

Britain’s abundance of coal – as well as ease of access – was a crucial ingredient in this historic turning point, fueling the steam engines that helped transform society.

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

Even though most mines in the UK have closed, their centuries-old history is not necessarily over. In Scotland, work is underway to determine how water that has flooded old disused mines can be used to provide carbon-free heating to buildings.

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

According to those behind the project, Glasgow and Rutherglen were home to some of Scotland’s busiest coal mines. After they were closed, natural flooding filled them with water at around 12 degrees Celsius.

Mike Stephenson, who until recently was executive scientific director of decarbonisation at the British Geological Survey, told CNBC that the project was “to do research on heat in coal mines and also, to some extent, if you can store the heat in the old coal mines”. .”

Stephenson said that at the site where the work is taking place, the team was “experimenting with…how fast the water flows between these mines, the temperature of the water, how…fast, if you pull out of hot water, does the water replenish – so how quickly does the heat return.

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

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

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

The project has progressed over the past 12 months or so. In the summer of 2021, it was announced that pumping tests had been completed and samples had been taken from 10 of the boreholes at the site.

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

The water in the mine between 50 and 90 meters below Glasgow is between 11 and 13 degrees Celsius, he added. For comparison, the average Scottish groundwater temperature is 10 degrees, MacDonald said.

Potential uses

According to the UK Coal Authority, 25% of residential properties in the UK are located on coalfields. As a source of heating, the potential of flooded underground mines such as those being researched in Glasgow appears to be considerable.

Citing its own calculations, the Coal Authority says that “the constant resupply of water to these mines could potentially provide a resource large enough to meet all the heating needs of the coalfields”. It could also have applications in industries such as manufacturing and horticulture.

“The water from these mines is a sustainable, low-carbon heat source, which under the right conditions can compete with public supply gas prices and deliver carbon savings of up to 75% compared to gas heating,” he notes.

Many governments are trying to move away from coal, but it still plays a crucial role in many countries. According to the International Energy Agency, coal provides about a third of the world’s electricity production.

Last December, the Paris-based organization said coal-fired power generation was expected to reach an all-time high in 2021. Regarding coal generation, the IEA said it was “expected that it peaks in 2022, then plateaus as demand flattens.

While it was crucial for the industrialization of the planet and remains an important source of electricity, coal has a considerable impact on the environment.

The US Energy Information Administration lists a range of emissions from burning coal. These include carbon dioxide, sulfur dioxide, particulates and nitrogen oxides.

Elsewhere, Greenpeace has described coal as “the dirtiest and dirtiest way to produce energy”.

In the North East of England, the South Tyneside Council is working on a project to revitalize part of the region’s mining heritage.

According to the council, the £7.7 million ($10.4 million) Hebburn Minewater project “will draw geothermal energy from the abandoned flooded mines of the former Hebburn colliery”.

The initiative aims to provide heat to several buildings belonging to the municipality using mine water from the old coal mine, opened at the end of the 18th century and closed in 1932.

The project is centered on the drilling of two boreholes. A water source heat pump will extract heat from the mine water, after which it will be compressed to a much higher temperature. After being piped to an energy center, a new network of pipes will be used for distribution.

The council is working on the project, which is due to be completed in June 2023, alongside Durham University and the Coal Authority. Last October, it was announced that tests had shown that the water temperature in the mine was warmer than initially thought.
New life

Attempts to use hot water from flooded mines are not unique to the UK In 2008, a facility described by the European Commission as the world’s first mine water power station opened in the Netherlands. A similar project based on using mine water to heat buildings in Asturias, northern Spain, has also been developed.

Back in South Tyneside, Councilor Ernest Gibson, whose memoir covers climate change, spoke to CNBC about the industry’s deep-rooted relationship with the region and his hopes for the future.

“The region’s economy has declined [as] as soon as the coal mines close,” said Gibson, a former miner.

He explained how the closure of a colliery affected not only the mining industry, but also others like the steel and transport industries, as well as smaller operations like local shops and the “rag picker”, a term for a person who would buy, collect and sell ancient objects.

Gibson went on to tell CNBC he’s “proud” that old coal mines are once again in use.

“The collieries closed but… they relaunched in a different format,” he said, later adopting a more philosophical tone. “It’s like life: everything changes, nothing stops. And I think that’s for the best.
Source: CNBC

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