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 laying 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 pipe-line 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 cover 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 aluminium smelting industry and to provide local electricity supplies.
With little modern modification and only general maintenance needed the huge network and dams occupy 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 per cent by 2020 with renewables to provide the equivalent of 80%.
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 50 metres deep, ending 35 meters 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, half-time of a Ranger’s match
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 upto 100 years. This fore-sight free of the modern trend toward materially efficient manufacturing will see their interrupted operation continue long into this century.
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 blue-prints. 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 4×4 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.