The facility, New Zealand's only aluminium smelter,[3] is at Tiwai Point, near Bluff. It imports alumina and processes it into primary aluminium. The plant's alumina is supplied from refineries in Queensland and the Northern Territory of Australia. Around 90 per cent of the aluminium produced at NZAS is exported, mainly to Japan.[4]
The smelter was opened in 1971[2] following the construction of the Manapouri Power Station by the New Zealand government to supply it with electricity. It uses 13 percent of New Zealand's electricity,[5][6] and is reported to account for 10 percent of the Southland region's economy.[7]
Rio Tinto has threatened to close the smelter several times, for example in 2013 and 2020, but to date closure has been deferred after renegotiation of the price it pays for electricity.[8][9][10][11] As of January 2021, Rio Tinto announced that it had reached an agreement with its power supplier Meridian Energy to pay a lower price in return for keeping the smelter running until December 2024.[12][13] In July 2022, NZAS signalled that it would once again offer to remain open if it could secure new power agreements on favourable terms.[14] In May 2024, new twenty year electricity contracts were agreed with three suppliers, allowing the smelter to remain open until 2044.
There are concerns regarding the environmental legacy of waste stockpiled at the site, near to an eroding beachline.[15]
^"Aluminium". riotinto.com. Archived from the original on 2017-01-13. Retrieved 2017-01-12.
^Grant, David. "Aluminium smelter, Tīwai Point". teara.govt.nz. Te Ara - The Encyclopedia of New Zealand. Archived from the original on 2017-01-13. Retrieved 2017-01-12.