Fuel and energy resources, Southern Uplands
|Stone, P, McMillan, A A, Floyd, J D, Barnes, R P, and Phillips, E R. 2012. British regional geology: South of Scotland. Fourth edition. Keyworth, Nottingham: British Geological Survey.|
Fuel and energy resources
There is a long history of coal mining in the south of Scotland though the two coalfields, Sanquhar and Canonbie, are relatively small by comparison to those to the north (Ayrshire and Douglas) and south (Cumbria, in north-west England) to which, respectively, they are geologically linked. The geology of the coal-bearing successions is described in Chapter 6 of this account.
The earliest workings at Sanquhar were opencast pits or adits driven into the hillsides, but by the end of the 18th century deeper underground mining was in operation. The ‘New Statistical Account of Scotland’, published in 1845, reported three pits in operation exploiting the Splint, Calmstone and Creepie coals. Deep, underground mining was much extended in the late 19th century, supplying good-quality steam coal, and continued through the early part of the 20th century. Some idea of the intensity of the mining operations is given by P912375, which shows the distribution of collieries in about 1935. Deep operations came to an end in the early 1970s, but at the beginning of the 21st century there was still limited opencast production in the Kirkconnel area.
At Canonbie there are records of exploratory boreholes from as far back as the late 18th century, and three seams were being worked underground as early as 1805. How ever, deep mining there was always much more limited in scale than that at Sanquhar, and effectively ceased in 1922, with only intermittent, small-scale operations continuing for a few years thereafter. The small outcrop of the Canonbie coalfield has a buried extension, concealed beneath Permo-Triassic strata, southward from Rowanburn (NY 410 771) and thence beneath the border and the Solway Syncline until it links with the Cumbria coalfield in north-east England. It is only from the 1970s, and the application of modern seismic methods controlled by deep boreholes, that the significant extent of this concealed coalfield has become apparent. Though there is currently no mining activity at Canonbie a substantial coal resource remains in the concealed coalfield. Also of interest is its potential for coalbed methane generation, since boreholes have established relatively high seam-methane levels, and the contiguous Cumbria coalfield is well known to be gas-rich. An associated possibility arising from methane generation would be the sequestration of CO2 into the coal seams. The character and quality of a coal is determined by the conditions in the swamp in which it was formed and by its subsequent burial history. The effects of temperature and pressure over long periods of geological time tend to expel water and volatile constituents from coal. Thus, a coal that has been subjected to elevated temperatures typically exhibits a low volatile content, a high carbon content and high calorific value; it is said to have a high ‘rank’. Conversely, coals that remain high in volatiles and have a relatively low carbon content and calorific value are said to be of low ‘rank’. The coals in southern Scotland’s Canonbie and Sanquhar coalfields are broadly middle ranking.
Peat has been used for fuel in the past on a minor scale throughout the south of Scotland, basically wherever proximity of habitation and available resources made it economic. The only large area of peat which has been worked on a commercial scale is the Lochar Moss (NY 040 715), south-east of Dumfries, though this is mainly for use in horticulture rather than as a fuel.
Alternative energy sources
At the present time, early in the 21st century, nuclear energy is generated in the south of Scotland region considered here at the Torness power station, on the North Sea coast south-east of Dunbar (NT 745 752); an older nuclear power station, at Chaplecross to the north-east of Annan (NY 216 697), has ceased operations and is being decommissioned. In the search for replacement ‘green’ energy, many of the more exposed upland areas have recently seen the development of windfarms to take advantage of the natural meteorological conditions. These hilltop sites commonly have only a thin veneer of superficial deposits, fragile soil and a vegetation cover that regenerates only slowly; all are vulnerable to any disruption of the natural surface drainage. Hence it is important to minimise disturbance during construction phases if serious and long-term problems of upland erosion are to be avoided. As the engineering challenges are met, there is an increasing tendency to site windfarms offshore, and such developments have already begun in the Solway Firth.
Hydroelectricity is generated from the far-sighted Galloway Power Scheme which was initiated in 1929 and completed in the early 1930s. Water flow into the River Ken catchment is regulated by dammed reservoirs in the upper part of the valley and to the west of New Galloway at Clatteringshaws Loch, which was much extended as part of this enterprise; from Clatteringshaws, water is fed into the Ken catchment via a tunnel to Glenlee. Electricity is generated at several stations including the Tongland Power Station (NX 697 538), just to the north of Kirkcudbright, where a visitor centre is located. Over the decades, the formerly stark, concrete dams, powerhouses and associated reservoirs have gradually blended into the landscape so that they now form an attractive visual asset. The scheme is small in comparison with those in the Highlands but has proved a good investment and at the beginning of the 21st century was upgraded with additional turbines to maximise generation capacity.
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