Cruachan Power Station

Useful Information

Location:	Dalmally, Argyll PA33 1AN. North bank of Loch Awe, 30 km east of Oban on A85. (56.394495, -5.116185)
Open:	APR to OCT daily 9:15-16:45, tours every 30 minutes. NOV to MAR Mon-Fri 9:15-15:45. [2024]
Fee:	Adults GBP 7.50, Children (5-15) GBP 2.50, Children (0-4) free, Seniors GBP 6.50, Students GBP 6.50. Green tourism offer: visitors arriving by public transport or bicycle will get discounted rates. [2024]
Classification:	Factory
Light:	Incandescent
Dimension:	VR=396 m.
Guided tours:	D=30 min. No bags or cameras allowed on the tour. V=50,000/a [2013]
Photography:	not allowed
Accessibility:	Visitor Center: yes. Tour: no
Bibliography:
Address:	Cruachan Visitors Centre, Dalmally, Argyll PA33 1AN, Tel: +44-1866-962-630. E-mail:
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then. Please check rates and details directly with the companies in question if you need more recent info.

History

1930	original idea for a hydroelectric power station by Sir Edward McColl.
1947	Tom Johnston, wartime Secretary of State for Scotland, forces the power station through Parliament.
1950	begin of construction of dam.
1959	begin of construction of underground parts.
15-DEC-1965	inaugurated by Her Majesty The Queen.
2009	Visitor Center refurbished.
2012	power station receives the Institution of Mechanical Engineers' Engineering Heritage Award.
2019	Cruachan Visitor Centre awarded the Gold Award for Green Tourism.

Description

Since Tony Oldham visited the site 20 years ago, a lot happened. There is now a modern Cruachan Visitor Centre with an interesting exhibition about hydroelectric power. And the café was renamed Hollow Mountain Cafe. But still it is recommended to book ahead to avoid waiting time. After Corona, they offer online booking.

The original idea for a hydroelectric power station at this place was from Sir Edward McColl, a Dumbarton-born engineer and pioneer of hydropower in Scotland, already in 1930. At this time it was not realized until Tom Johnston, wartime Secretary of State for Scotland, heard about this idea and forced it through Parliament in 1947. In 1950, the construction of the dam began, as designed by the civil engineer James Williamson. The dam was built, the tunnel drilled, the cavern for the turbines excavated, then the turbines were broken down into manageable loads for transportation through the tunnel and reassembled inside. Outside, a 275,000 V transmission line was constructed to connect the dam with Dalmally substation near Cruachan. After 15 years, the largest reversible pumped storage hydro system in the world was opened by Her Majesty The Queen on 15-OCT-1965. A third turbine was added in 1966, and a fourth in 1967, and Cruachan Power Station reached its full capacity.

The mining of the underground tunnel and chamber took six years. At this time, the miners did what is now called the "traditional" mining technique. They drilled holes into the rock at the face of the tunnel with handheld compressed air drills. The holes were filled with explosives, gelignite, and the next section of the granite was blasted. Then the shift changed, and when the next arrived the bad air from the explosion had been replaced by fresh air, and they started to remove the loose rocks and drill holes. They were quite efficient and even held the world tunneling record once. Beneath the tunnel and the machine hall, the also drilled the tailrace tunnel connecting river Awe with the machin hall and the tunnel connecting the machine hall with the upper reservoir. And there is a shaft from the machine hall to the surface for ventilation and for the cables. 36 men died in the construction of the power station and dam, the most spectacular accident was a collapse of the turbine hall roof which killed 15 workers.

Loch Awe is a 26 km long lake, which is less than 2 km wide, at most places it’s less than 1 km wide. It’s more like a dammed river, and actually that’s what it is, Awe Barrage Power Station dams the river, and so the upper part of the river and the loch are actually about 5 m higher than naturally. 4 km upstream from this dam is the Cruachan Visitor Centre, the water of Loch Awe is used by the reversible pumped storage hydro system. Many power stations, especially the cheaper ones, are producing the same amount of energy all the time, it takes hours to stop them and hours to start them, so it makes more sense to keep them running 24 h per day. Twice a day, at noon and in the early evening, people need much more energy for cooking and for light and TV, and as a result the power stations are not producing enough energy, but the rest of the day they produce too much energy. The energy which is not consumed is used to pump water from Loch Awe to the reservoir, which is 320 m higher. When more energy is consumed, the water runs down from the reservoir to Loch Awe and produces electricity. The direction of the water can be changed in minutes, so this energy is more or less immediately available.

In other words, this is a sort of energy storage, an accumulator, which stores energy in the form of positional energy. Of course, this is not for free, there is a loss of about 30 % of the energy, but still the other 70 % of the energy would also be lost otherwise. And the energy is available in a few minutes, which stabilizes the electric grid during fluctuations in consumption. So it is an essential part of any electric grid to have such storage facilities. And this necessity increases with the installation of regenerative energy like wind and solar power. Those power sources are volatile, depending on the amount of wind and sunshine, and it is essential to store the energy at least over the day, but probably if there is bad weather or a calm period over several days. There is even a special term: Dunkelflaute (dark doldrum) which means a period of time in which little or no energy can be generated with wind and solar power, because there is neither wind nor sunlight. For such periods, the storage of energy becomes increasingly important. The site was owned by the Scottish electricity company ScottishPower for a long time, but it is now operated by Drax, which is specialized in renewable power.

The tour begins with a 1 km coach ride to the heart of the mountain here you can see the 4 giant generators which can supply 100,000 KW in only 2 minutes. It is the highest head reversible power station in the world. There is a free exhibition and video, cafeteria, gift shop and picnic area. The whole set-up includes 24 km of tunnels which supplies water to the main reservoir high in the mountains above the power station. It is advisable to phone ahead and book so that you do not get held up for two hours by a coach party, like we did.

Text by Tony Oldham (2004). With kind permission.