British Aluminium’s Lochaber smelter complex was given its Parliamentary go-ahead in 1921 and came into operation in 1929. It was further extended between 1938 and 1943. By 1939, the works had expanded the output of BACo’s west Highland works by more than 30,000 tons per annum, accounting alone for over three-quarters of BACo’s total output (including that of its Norwegian works) and around four per cent of international primary aluminium production.
The civil engineering project to establish the works and its power supply required three arduous stages - spanning two decades - and necessitating no less than four discrete pieces of legislation. The first stage involved 2,000 men driving a tunnel through the solid rock of the Ben Nevis range from Loch Treig to Fort William.
When completed this fifteen-mile concrete lined water conduit was over seven times the length of the Tay Bridge, and daily conveyed 860,000,000 gallons of water drawn from a catchment area of 303 square miles. This concentrated natural power was then channelled down two steel pipelines falling nearly 600 feet to the hydro- station, where ten giant generating units produced 10,000 horse-power each to supply the factory.