By Andrew Mc Barnet


Business • People • Technology

Interest in coal mines is heating up

A hamlet in the English county of Nottinghamshire, so small it has a church but no shops, is earning at least a footnote in Britain’s energy transition. This is because the community of Ratcliffe-on Soar neighbours the country’s last coal-fired power station, operated by German energy company Uniper. The plant is definitively due to close in October this year after a brief reprieve related to the threat to European power supplies after the Russian invasion of Ukraine. Ironically, in recent years coal imported from Russia had been its main source of fuel.

Once the dying embers are extinguished at Ratcliffe-on-Soar, Britain will become one of the first countries in the world to give up on the use of coal for generation of electricity, a pledge made in 2015. Since the world’s first centralised public coal-fired generator opened in 1882, at Holborn Viaduct in London, Britain had some continuous coal-fired power generation until the first ‘coal-free’ day was declared in April 2017.

Actual mining of coal in the country has reached almost zero, the final chapter in the extraordinary story of how coal fueled Britain’s emergence as the first great power of the First Industrial Revolution thanks to manufacture of iron, factory textile mills, steamships, and steam engines for transport and many other purposes.

But, the UK is not yet done with all its old mineworkings, so the country’s association with coal seems destined to live on. The first forays into developing the potential energy from  low enthalpy heat for local district heating, using open loop ground source technology to recover heat from abandoned flooded coal mines, is underway.

Looking back, possibly unbeknownst to many, the first effective application of steam power, a full century before Robert Stevenson’s famous 1830 Rocket passenger locomotive, was patented by Thomas Savery in 1698. Its purpose was to drain water from coal mines. This was followed by more sophisticated systems developed by Thomas Newcomen around 1712 and 50 years later by James Watt.

Demand for British coal rocketed in the 19th century and reached its peak in 1913 when 292 million tons were produced for home consumption and export (96 million tons) from 3270 operating mines. In 1920, 1.19 million people were working in the mines, 1 in 20 of the country’s workforce. The Mines and Collieries Act of 1842 had forbidden boys under 10 years of age and all females to work underground as so called hurriers and thrusters (although the legislation was for some time not always adhered to). Pit ponies became the alternative for deep mines; at peak in the early 20th century there were some 70,000 registered animals, the last retiring from work in a Northumberland mine coalfield in 1994.

After experiencing a visit to the pit face, George Orwell in his pre-Second World War Road to Wigan Pier acknowledged the significance of coal to society: ‘Our civilisation, pace Chesterton, is founded on coal, more completely than one realises until one stops to think about it. The machines that keep us alive, and the machines that make machines, are all
directly or indirectly dependent upon coal. In the metabolism of the western world the coalminer is second in importance only to the man who ploughs the soil.’

The UK’s dependence on coal was still evident in 1950 when 90% of all energy (including industry, railways, heating, cooking, etc) was still sourced from coal. But so-called King Coal had been in steady decline since the 1920s as competition squeezed exports. This was only to become steeper, not fully appreciated by the post-war Labour government under Clement Atlee. It nationalised the industry in 1946-7 honouring the party’s Clause 4 ideological commitment to public ownership of key industries (amended in the mid-1990s under Labour Party leader Tony Blair).

The 1950 Plan for Coal proved hopelessly optimistic in expecting to increase output from 184 million to 250 million tons by 1970. In 1956, thanks to government investment, 700,000 men produced 207 million tons of coal but by 1971, fewer than 290,000 workers were producing 133 million tons at 292 collieries. The industry was soon in further freefall. The advent of North Sea oil and gas plus the nuclear power station programme took its toll on coal demand. Diesel and electric trains rapidly replaced steam engines in the 1970s. On the domestic front, the 1956 Clean Air Act, inspired by the ‘great smog’ in London in 1952, was instrumental in a switch away from coal-fired central heating.

The legend of Margaret Thatcher maintains that the ‘Iron Lady’ delivered a fatal blow to both the coal industry and organised trade unions when crushing the mineworkers strikes of 1984-85 over pit closures and output reductions. It is said to be her act of vengeance for the early 1970s militant mineworkers’ action that arguably forced Tory Prime Minister Edward Heath out of office. But, regardless of the ruthless action and damage to mining communities, the truth in retrospect is that she probably only accelerated a process well underway. Indeed, governments (Conservative and Labour) had been implementing mining closures for decades. Immediately before the strike, 170 mines employed 148,000 workers and produced 120 million tonnes of coal. By the time the Tories privatised the coal industry a decade later, around 30 mines produced 50 million tonnes and employed 7000 workers, less than 1% of the 1950 post war peak. In 1994, coal only constituted 12% of Britain’s fuel production, with 80% coming from North Sea oil and gas and the other 8% mainly nuclear power.

Britain’ adoption of renewables in the current century effectively spelled the end of coal, the last deep mine closing in 2015. Ex-Prime Minister Boris Johnson in a pre-COP26 visit to Glasgow in 2021 claimed green credentials for a previous Tory administration. He joked to reporters that ‘Thanks to Margaret Thatcher, who closed so many coal mines across the country, we had a big early start and we’re now moving rapidly away from coal altogether.’ Unsurprisingly the remark invited swift all-party rebuke with critics pointing to the devastation caused in mining communities by abrupt closures in Scotland and the North of England.

Carbon Brief reports that, as of the end of 2023, the 104 terawatt hours (TWh) generated from fossil fuels in 2023 was the lowest level in 66 years. Electricity from fossil fuels fell by two-thirds (199TWh) since peaking in 2008. Within that total, coal dropped by 115TWh (97%) and gas by 80TWh (45%). This is attributed to the rapid expansion of renewable energy (up six-fold since 2008, 113TWh) and by lower electricity demand (down 21% since 2008, 83TWh).

Low-carbon sources made up 56% of the total, of which renewables were 43% and nuclear 13%. The remainder was from imports (7%) and other sources (3%) such as waste incineration. Overall, the electricity generated in the UK in 2023 had the lowest-ever carbon intensity, with an average of 162g of carbon dioxide per kilowatt hour (gCO2/kWh), but Carbon Brief notes that this is well short of the government’s ambition for 95% low-carbon electricity by 2030 and a fully decarbonised grid by 2035.

As for Boris Johnson’s misguided aside in Glasgow, he would have been much better served boosting the promise of environmentally friendly district heating from the naturally heated water in flooded coal mines. The city is home to the recently established Glasgow Geoenergy Observatory operated by the British Geological Survey (BGS). Its mission and facilities are well described in a paper by A. Monaghan et al. at the EAGE’s 2023 Near Surface Geoscience in Edinburgh (available in Earthdoc). The mine water geothermal research facilities are intended to provide ‘an at-scale underground laboratory to facilitate collaborative research to improve understanding of subsurface processes, environmental and induced change. It offers scientific infrastructure for investigating the shallow, low-temperature geothermal energy and thermal storage resources available in abandoned and flooded coal mine workings at depths of around 50-90 m. Such resources could provide sufficient heat for community-scale district heating networks and extensive thermal storage.’

An open access Energy Reports paper in 2020 on The theoretical potential for large-scale underground thermal energy storage (UTES) within the UK by J.G. Gluyas et al. concluded: ‘Our calculations indicate that the theoretical potential for large-scale underground thermal-energy storage in the UK is substantial, much larger than which might ever be needed and the location of such storage is well matched to the places where people live and work and therefore where the demand for heat occurs.

An EAGE Annual 2023 conference paper from Oldfield et al. on Regional-Scale 3D Geothermal Prospecting to Support Local Authorities in Delivering National Strategies focused on the potential of the old mineworkings of Selby, Yorkshire.

Although research and project development interest is taking off in a number of UK regions, the idea is not new and is being explored in a number of countries. Springhill, Nova Scotia, Canada inaugurated an ongoing system as far back as 1994 and the world’s first mine water power station opened in Heerlen, The Netherlands in 2008.

However, Gateshead Council, NE England, has already got off the mark with the largest mine water heat network in Britain and one of the largest in Europe providing hot water and heat to hundreds of homes and businesses. Three years in development, heat is extracted from mine water from 150 m below Gateshead town centre via three boreholes drilled into old flooded mine workings. The warm water is then then fed into a 6 MW water source heat pump that boosts the temperature of the water before it is distributed over a 5 km-long heating network. 

It seems mineworkings in the future may not be such a dirty word.