Tiwai Point, across the harbour from Bluff, is the location of an aluminium smelter which was opened in 1971. It is one of the 20 largest aluminium smelters of the world, producing the world's highest purity primary aluminium. The smelter uses up a significant amount of electricity which is mostly supplied by the hydroelectric Manapouri Power Station. It is the largest electricity consumer in New Zealand, using approximately one third of the total power of the South Island and 15% of the total power countrywide.