Located 1½ miles (2.5 km) east northeast of Fort William in W Highland, the Lochaber Aluminium Smelter is Britain's last such plant and is now operated by the multi-national GFG Alliance. Opened in 1929, this was the third aluminium smelter established in the Highlands of Scotland by the British Aluminium Company Ltd., the first being at Foyers (1896) and the second at Kinlochleven (1907). Such is the electricity requirement that economics favours the location of smelters in areas where power can be produced cheaply, rather than proximity to the source of aluminium ore. In 1982, British Aluminium merged with Alcan UK, a division of the Canadian multi-national Alcan Inc. Another merger followed in 2007 with the Canadian subsidiary of Rio Tinto, to form Rio Tinto Alcan Inc. The plant was sold to GFG for £330 million in 2016, but it remains a major employer in the area, with 175 staff producing 40,000 tonnes of aluminium annually. With an annual turnover of $6.8 billion (2016), the GFG Alliance links the business interests of Indian businessman P.K. Gupta (SIMEC, which operates in the shipping, energy and mining sectors) with those of his son Sanjeev (owner of the steel to engineering conglomerate, Liberty House).
Drawing water from the Lochaber Scheme, the plant includes the largest hydro-electric power station in the United Kingdom. The power-house contains twelve original generating sets from the 1920s, each with a Pelton turbine turning two 3.5-megawatt (MW) DC generators, together with three auxiliary 1.25 MW AC generators, giving a total theoretical output of 87.75 MW, although the maximum achievable is 65 MW. This vast quantity of electrical power is used to reduce imported aluminium oxide (alumina) to aluminium metal in eighty electrolytic cells, technology installed in the 1980s. These run 24-hours per day, seven days per week. Each micro-processor controlled cell draws 175,000 amps of power between 16 continuously-adjusted pre-baked carbon anodes and a fixed cathode to produce 1350 kg (2976 lbs) of metal daily. Cell maintenance is undertaken without switching off the power because, despite the enormous current, the voltage is too low to electrocute. The molten aluminium is drawn off and cast, using automated vertical casting machines, into 10-tonne ingots which are sent south by road or rail. Flue gases are treated to a high environmental standard and principally comprise carbon dioxide when expelled.