Sloy Power Station

Sloy Power Station stands in a remote, mountainous part of Argyll and Bute, north of the Cowal peninsula beside Loch Lomond. It sits three kilometres south-east of the Loch Sloy dam, where the water is stored before being sent through the mountain to the powerhouse. The dam itself, completed in 1949, was Scotland’s longest at the time, stretching 366 metres across the glen. Its construction doubled the length of Loch Sloy and deepened it by about fifty metres. German prisoners of war helped build the dam during the late 1940s. The reservoir now drains a catchment area four times larger than the original loch. The power station was opened in 1950 by the British queen mother after three years of building. Its four original generators were upgraded in the 1990s at a cost of £113 million, raising each unit’s output from 32.5 MW to 40 MW. Today the plant can produce 152.5 MW, making it the most powerful hydroelectric station in the United Kingdom. Every minute it draws 4.5 million litres of water from Loch Lomond through two-metre-wide tunnels bored through Ben Vorlich. The electricity travels away on 132-kV lines to feed the national grid. Visitors reach the site along the quiet road from Tarbet, six kilometres to the south. The dam and reservoir lie in a steep-sided valley high above Loch Lomond, with views across to the Arrochar Alps. Inside the power station building, the renewed turbines and control room show how modern engineering works alongside mid-20th-century design. The surrounding hills are thinly populated, so the landscape feels wild and undisturbed. From the dam crest, the long wall stretches across the gorge, holding back the expanded waters of Loch Sloy.