Dams steal the prize as the iconographic feature of hydroelectricity. However on the project so far I learnt how much of the engineering and secrets to the industry lie in the huge civil and underground earthworks deep within Scotland’s bedrock. Tolkienesque tunnels hewn through solid granite lead to massive engineering. Such as the 165m unlined access tunnel to Culligran Power Station.

Through a separate access tunnel, close to the base of Foyers’ Turbine Halls, is a 400m lined tunnel leading to a hall housing a side access portal. Calcium stalactites line the ceiling with everything coated in a thick film of solid lime. The echoey, impossibly deep rumbling sound of the generators starting had me peering into the gloom half expecting a wall of icy water to rush in.