Rio Tinto Restarts Tiwai Line With Contact Deal
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Rio Tinto will restart a mothballed production line at Tiwai Point aluminium smelter, backed by a new wind farm deal with Contact Energy.
The companies signed a letter of intent for a power purchase agreement to support restarting Line 4, which has been idle since 2020. The arrangement would see the smelter become a long-term customer for Contact's recently approved Southland Wind Farm.
Line 4 restart would require around 50MW of additional electricity and deliver about $100 million in annual export revenue when fully operational. It would produce approximately 30,000 tonnes more aluminium per year.
The Southland Wind Farm, fast-tracked through government approval, is expected to generate more than 325MW of renewable electricity — enough to power 150,000 households.
Armando Torres, managing director of Rio Tinto Aluminium Pacific Operations, said the agreement reflects shared commitment to low-carbon growth and energy security.
"This Letter of Intent represents a practical step toward restarting Line 4 at Tiwai, strengthening New Zealand's position as a producer of low-carbon aluminium, supporting jobs, increasing exports, and contributing to a more resilient electricity system. The aluminium produced by Tiwai is in high demand and is an essential part of the energy transition globally," Torres said.
NZAS general manager Michelle Henderson said the restart builds on long-term energy contracts secured for the smelter in 2024.
"Building on our existing electricity arrangements with Contact, we are pleased to have them partner on the potential restart of Line 4. If approved, this increased production — targeted for 2030 with potential to be brought sooner — would bring more economic activity to Southland, further strengthening the local economy, and reinforcing Rio Tinto's commitment to Southland into the future," Henderson said.
Contact CEO Mike Fuge said committed customers were critical for bringing new renewable generation online.
"Having a credible baseload partner such as Rio Tinto is critical bringing for new renewable generation online. This letter of intent helps underpin our Southland Wind Farm and shows how industry and renewable energy can work together to deliver long-term benefits for both Southland, and New Zealand," Fuge said.
Southland Regeneration and Ngāi Tahu representative Terry Nicholas welcomed the initiative.
"Southland Regeneration and Ngāi Tahu welcome this forward-looking initiative, which perfectly aligns with our vision for a sustainable, high-value regional economy," Nicholas said.
"This agreement strengthens our growing partnership with both Rio Tinto and Contact, ensuring that future industrial growth reinforces our commitment to environmental prosperity and community resilience.
"We look forward to exploring the wide-ranging future opportunities this unlocks for our people and the community at large, particularly in high-skilled jobs, clean energy innovation, and long-term wealth creation for Southland."
Both parties will now negotiate a final power purchase agreement, subject to commercial terms and regulatory approvals. Line 4 could restart in 2030.