UK-Australian metals producer Rio Tinto will increase production at its 335,000 t/yr Tiwai Point aluminium smelter in New Zealand from 16 June, ending an electricity demand reduction agreement with New Zealand utility Meridian Energy.
The plant will reach full capacity in August, although Meridian Energy can ask Rio Tinto to cut its electricity use at Tiwai Point two months after the ramp-up finishes.
Rio Tinto agreed in March that it would operate Tiwai Point at a reduced rate throughout New Zealand's winter because of energy security issues. It had originally planned to start ramping up production again from August.
But a bout of rain in New Zealand's North Island in April-May refilled many of the country's hydroelectric lakes — which provide a large portion of the country's base-load power — easing electricity supply concerns and allowing Rio Tinto to modify its reduction agreement with Meridian and ramp up production early.
Water levels in New Zealand's hydroelectric lakes declined from January–March, falling to 77pc of their historical seasonal averages in early April. But water levels rebounded to 92pc of their historical averages over the week to 25 May, according to New Zealand transmission operator Transpower.
Rio Tinto's Tiwai Point smelter has operated at a reduced rate since late June 2024, when the company wound down one-third of the plant's operations at Meridian's request. It produced 290,000t of aluminium at Tiwai Point in the 2024 calendar year, the company said in its 2024 annual report.
New Zealand was facing an electricity shortage at the time, with low hydroelectric flows and gas shortages straining its national grid.
All of Rio Tinto's electricity needs at Tiwai Point are supplied by hydroelectric plants. It generated zero scope 2 emissions — from electricity purchases — at its New Zealand operations last year, although it produced 500,000t of CO2 equivalent scope 1 emissions — from its direct operations — in 2024, according to its annual report.
