This feature was shot throughout 2010. A full edit of 154 images available on request. The following text was written by photographer Toby Smith, and is available with the images.
On a clear winter’s night in the Scottish Highlands the combination of starlight and snow create a silver lighting effect bright enough to read newsprint. 1200m above sea-level the mercury plunges to -15?C with the week’s fresh snow and ice lying heavily on a Loch frozen solid. This man-made reservoir, Lochan-na-Lairige, is held back by the mighty Lawers Dam. Over 344m long and 42m in height with the strength of its buttress supports mirroring the steep granite sides of a natural valley in the shadow of Scotland’s 3rd highest mountain. 415m down the mountain side, on the shore of Loch Tay, Finlarig Power Station is connected by a massive steel pipeline to the base of the dam and generates electricity for the National Grid at times of peak load.
Controlled automatically from Perth its turbines can spring into life almost instantly as the incredible potential energy of the water rushes through its blades turning huge generators on an axel weighing 65 tonnes. Uphill at the reservoir, denied meltwater by the freezing temperature, the water level decreases slowly leaving the thick ice suspended in air. Without warning a fissure explodes across the surface, the ice drops, sending a shockwave echoing around the valley sides. The loch grumbles as the surface settles and electricity coarses through the grid into Scottish homes as it has done since the station’s commissioning in 1956.
This Scottish dam and connected power station are just one system in part of an incredible network of hydro schemes that have a rainfall catchment area equivalent to 25% of the total land area of Britain. The region contains Britain’s highest mountains and largest inland lochs which, combined with high rainfall, make hydro electricity viable. Hydro electricity is produced using the power of running water to turn the turbines of generating sets in power stations. The technology dates back to the late 19th Century when the first privately owned hydro electric power stations were built to power the aluminum smelting industry and to provide local electricity supplies.
By 1965, 54 main power stations and 78 dams had been built across Scotland, providing a total generating capacity of over 1,000 megawatts. (A megawatt (MW) = 1,000,000 watts). Over 300 kilometers of rock tunnel had been excavated and a similar length of aqueducts and pipelines constructed. Over 32,000 kilometers of electricity network was built to distribute the electricity throughout the north of Scotland, with a further 110 kilometers of submarine cable taking power to the major Scottish islands. All this work was achieved by a workforce that averaged 4,500, and which, at its peak, numbered about 12,000. In many cases, the workforce was made up of a mixture of British workmen and German and Italian former prisoners of war.
With little modern modification and only general maintenance needed the huge network and dams have a rainfall catchment area equivalent to one quarter of the UK’s surface area but are entirely within a landscape coined as untouched raw, wild, pristine, beautiful and natural. This silent acceptance, not ignorance, by the Scottish people is of stark contrast to the modern battle between the protection of landscape and mounting defence of a modern implementation of wind or tidal energy. These hydro systems are both the current foundation of a proud country’s electricity provision but also the historical proven integration of a nation poised to become a champion of new renewable energy delivery.
This year the Scottish first minister invited further development of the low carbon economy as more than 450 leading figures from international finance, energy and other sectors gathered in Edinburgh to explore opportunities and help accelerate private investment in a global market that is forecast to grow to £4.3 trillion by 2015. Up to 60,000 new green jobs could be created some 28,000 of them in Scotland. In another government directive Scotland is committed to cutting CO2 emissions by 42% by 2020, with renewables to provide the equivalent of 80% of the country’s energy requirements.
For years now, the UK has been the enigma of European renewables; endowed with massive resources but languishing at the bottom of the implementation table. In addition to an existing installed capacity of 1.3 Gigawatts (GW) of hydro-electric schemes, Scotland has an estimated potential of 36.5 GW of wind and 7.5 GW of tidal power (25% of the estimated total capacity for the European Union), and up to 14 GW of wave power potential (10% of EU capacity).
Much of the original system was designed, built and engineered during a proud period of Britain’s industrial heritage. Generators, pipework, structures and regulation systems were over-engineered and built with a life-span of up to 100 years. This foresight free of the modern trend toward materially efficient manufacturing will see their interrupted operation continue long into this century.
Although much of the control and monitoring systems have been upgraded the brass name-plates of long forgotten engineering firms from Britain’s industrial past, such as Bradford, Liverpool, Edinburgh and Glasgow, still adorn the humming machinery. The living engineering and network of water catchment systems is kept in meticulous order by a team of dedicated, locally recruited engineers that proudly clean, paint, service and grease the moving parts.
Much of the temperaments and intricate knowledge of the systems are passed on through training, oral history or an occasional reference to the original imperially measured blueprints. The reality of working in the remote landscape, especially in winter, is viewed as both a challenge and joy. Engineers work in pairs, often hours from the nearest road, in specially prepared 4x4 vehicles. The concept of health, safety and common sense is adhered to without question when the dangers of working at height, in confined spaces and with high voltage electricity are very real.
In the northern part of the Affric-Beauly scheme the main dam is at Loch Monar, an unusual double curvature concrete arch. A 9km tunnel carries water to Deanie Power Station located underground near the western end of Loch Beannacharan. Below the Falls of Farrar is the underground Culligran Power Station receiving water from Loch Beannacharan.
The valley and waters of the Affric-Beauly scheme are recognized as important for salmon and compensation water is released. The Glen of Strathfarrar in which much of this scheme is housed is a wild and protected area of outstanding natural beauty.
In 1974, the Foyers combined pumped storage and conventional hydro scheme began operating on the shores of Loch Ness. When Foyers is generating, water is allowed to flow through tunnels from Loch Mhor through the turbines producing electricity during times of peak demand. At times of low demand, surplus electricity is drawn from the system and fed to the machine sets. These now operate in reverse, and the generators acting as motors, drive the turbines which now act as pumps. In this way water is pumped back up from Loch Ness into Loch Mhor ready for the next generating requirement.
The two machine sets are located at the bottom of shafts, over 50m deep, ending 35m below the surface of the Loch. Foyers can begin generating electricity from a standing start in under two minutes, but if conditions demand, the machines sets can be spun in air to act as “spinning reserve”. In this way electricity can be supplied within 30 seconds. A modern reality where peak demand often corresponds with the public activity such as boiling a kettle nationwide for morning tea between 7 and 8am, or during half-time of a Glasgow Rangers or Celtic football match.
When generating at full load, the two turbines pass water into Loch Ness at the rate of 200 cubic metres per second. When pumping at full power they can lift 167 cubic metres of water per second from Loch Ness up through the tunnel system.
The Tummel Valley catchment area extends over 1,800 square km of the Grampian Mountains and includes some of the most rugged and remote parts of the Scottish Highlands, much of which can remain snow covered for several months of the year. The snowfields act as ‘nature’s batteries’, storing water until the snow melts
Rannoch Power Station, on the northern shore of Loch Rannoch, has been generating hydro electricity for over 70 years, fed by water brought by pipeline and tunnel from Loch Ericht.
Errochty Power Station is the largest on the Tummel scheme. It is supplied via a 10km tunnel from Loch Errochty. The buttress dam on Loch Errochty is 364m long and 49m high. Water from Loch Tummel is diverted via tunnel and pipeline to Clunie Power Station before flowing on to Loch Faskally.
Pitlochry is the last power station in the Tummel scheme and by the time the water reaches this point it may already have generated electricity up to five times during its course down the Tummel Valley. Pitlochry Dam with its associated fish ladder attract up to 500,000 tourists.
The Breadalbane scheme lies in the mountainous region around Loch Lyon, Loch Earn and Loch Tay in Perthshire and contains several deep glaciated valleys with high peaks well above 900m high. The steep slopes and heavy rain and snowfall of this region combine to create favourable conditions for the production of hydro electric power.
Lochay Power Station is fed from Stronuich through a pipeline and tunnel system over 9km long and is the largest station in the Breadalbane scheme. The Falls of Lochay above the power station were previously a barrier to salmon but the small power station built at the falls was equipped with a Borland Lift in order that salmon can now bypass this obstacle. Two pool type ladders were also built upstream to open up the spawning gravels of the whole river.
To the south east lies the St Fillans section of the scheme with two main dams and three power stations. Loch Breaclaich collects water from a series of small streams which would otherwise flow north into Loch Tay. This water is carried from Loch Breaclaich through a system of tunnels and aqueducts to Lednock Power Station on the shores of Loch Lednock.
St Fillans Power Station at the foot of Loch Earn is fed water from Loch Lednock via a tunnel and discharges into Loch Earn. The machine hall of this station is a cavern hewn out of solid rock. From Loch Earn, water is diverted into a tunnel to feed Dalchonzie Power Station.
To the west of Loch Lomond is the rugged and mountainous landscape of Argyll. The waters of Loch Sloy are held back by Sloy Dam which is 357m long and 56m high. Water is diverted into Loch Sloy from areas well to the north and south via a system of tunnels and aqueducts.
A tunnel 3km long carries water from Loch Sloy through Ben Vorlich, which towers almost 940m above Loch Lomond, to the valve house immediately above Sloy Power Station. From here the water plunges down the side of the mountain through four large pipelines into the power station.
Sloy Power Station, the largest conventional hydro electric power station in the UK, can be operating at full load within 5 minutes of a standing start and it is this almost instant availability that makes it ideal for use during times of peak demand.
In the mountains to the north west of Sloy is Loch Shira. This reservoir is 338m above sea level and was created by building a dam across Glen Shira.
The Salmon Story
Many major river systems in the Highlands have long been renowned as breeding grounds for salmon and trout. As far back as the 1943 Act of Parliament that established the North of Scotland Hydro Electric Board, there was a requirement on the company to avoid, as far as possible, injury to fisheries and the stock of fish. When the power stations and dams were constructed during the second half of the last century, great care was taken to minimize their environmental impact.
Fundamental to helping preserve fish stocks is the need to maintain a flow of water in the rivers and streams that fish have access to. In these rivers, carefully regulated water flow, known as compensation water, is released downstream from the dam to protect the natural water environment. This helps the eggs hatch and the young fish to feed and grow. It also assists the adult salmon and sea trout ascend the river to their spawning grounds. In some cases, such as at Pitlochry Dam and Power Station in Perthshire, the hydro electric infrastructure would have created an impassable barrier to salmon unless some means of allowing them to by-pass the obstruction was provided. The solution was to build fish passes. There are two types of fish pass, the fish ladder and the fish lift, known as the Borland lift. At Pitlochry a fish ladder comprising of a series of pools which are connected by underwater pipes. The ladder is 310m long and has 34 pools. The fish are attracted to the fish ladder by the flow from a small discharge of compensation water near the ladder’s entrance.
Lochay Power Station has an example of a Borland lift. This type of fish pass works on the same principle as a canal lock. Downstream of the dam, the fish are attracted by the flow of water into a pool at tailrace level. A sluice gate is closed at set intervals and the water gradually fills the pool and a shaft which connects it to an upper pool. As the water level rises, the fish are lifted to the upper pool which is at the same level as the reservoir above.