Coal and Climate

While Wales is working hard to drive forward a positive climate agenda, with a target of 100% renewable electricity by 2035, our industrial past casts a long environmental shadow. Here Jennifer Protheroe-Jones, Principal Curator – Industry looks at our industrial history and its impact.

Wales was an early and unwitting contributor to climate change.

The 1851 Census showed that Wales was the first nation to have more people employed in industry than in agriculture, the important switch having probably occurred in the mid to late 1840s.

Wales was a notable international centre of industry in the mid 19^th century, being one of the most important iron producing nations, and the centre of both the world copper and tinplate industries. Plentiful easily worked coal underpinned all these industries – to fuel furnaces, to power steam engines that drove machinery and locomotives that hauled raw materials and finished products.

An ocean of railway wagons loaded with coal in sidings adjacent to Roath Dock, Cardiff, awaiting shipment in March 1927. The initials on the wagons identify a range of major colliery companies: Burnyeat, Brown & Co Ltd; D.Davis & Sons Ltd; Nixon’s Navigation Coal Co Ltd; United National Collieries Ltd.

Welsh steam coal is ideally suited to steam-raising. It burns with relatively little smoke, produces limited amounts of ash and produces a great deal of heat. As it burns, steam coal fissures but does not crack into small pieces. The fissures allow the coal to burn from the inside as well as from the outside, considerably increasing the heat output and so increasing the steam-raising properties of the fuel. Because steam coal does not break into small pieces as it burns, it sits on top of the fire bars and burns, rather than trickling through the bars as small fragments of unburnt coal which would go to waste amongst the ash. This property of not breaking into small pieces is specially relevant to fuel used in locomotives, because the vibration of the locomotive as it moves along the track tends to make poorer quality fuels break into small pieces which are wasted when they trickle through the fire bars into the ash pit. These properties made Welsh steam coal a premium fuel in wide demand.      

A few decades later, exports of Welsh coal would outstrip the large amounts being used by industries within Wales. By the start of the twentieth century, south Wales was the most important coal exporting coalfield in the world, supplying diverse countries with steam coal. In energy terms, the Bristol Channel was at this time the equivalent of the Persian Gulf a hundred years later. If high quality fuel capable of powering the widest range of machinery was required, then the coal-exporting ports of south Wales were key places to obtain it.

Aerial view looking south east over Cardiff (East Moors) Steel Works around 1960.

In the 19^th century the sight of smoke from works’ chimney stacks was regarded as a sign of prosperity. By the early 20^th century smoke from burning coal was increasingly recognised as a nuisance but regarded as unavoidable. It was not until after the second world war that serious efforts began to be made to reduce the volumes of smoke from industries and from coal fires in houses – and by this time oil was globally becoming a more important energy source than coal.

The burning of coal, oil and natural gas releases carbon dioxide and other greenhouse gasses that cause climate change. Internationally, today the largest uses of coal are in electricity generation, cement manufacture and in steel making. Coal ceased to be used to generate electricity in Wales in March 2020; coal continues to be used in the steel and cement industries. 

Tipping a railway wagon of coal at Cardiff Docks, early 20^th century. Some coals tended to break up so, instead of tipping the wagons directly into ships’ holds from a considerable height, the coal was tipped into a Lewis Hunter patent ‘coaling box’ (just visible below the copious coal dust) which was picked up by the dockside crane on the left and lowered into the ship’s hold, minimising the height that the coal was dropped.

The Welsh coalfields were intensively mined in the 19^th century and output peaked in 1913, declining thereafter due to exhaustion of accessible reserves of coal. Output in 1913 was 60 million tons, half of which was exported; in 2018 output was down to 1.1 million tons. Welsh coal output was in steep decline by the time climate change was widely recognised as a major global issue. Each year the world now produces over a hundred times as much coal as Wales did in 1913, when the Welsh coal industry was at its peak. Even back in 1913, Wales was only producing around 5% of world coal output – its importance at the time was that half of it was exported and that it was regarded as the premium fuel of its time.   

The complex web of communications that enabled Welsh coal to be traded internationally is explained in the Coal gallery at the National Waterfront Museum at Swansea.