Rio Tinto has inked deals to tap Edify Energy’s Smoky Creek and Guthrie’s Gap solar power projects for its Gladstone aluminium operations.

Under the agreements, Rio Tinto will purchase 90 per cent of the power and battery storage capacity generated by the projects for 20 years.

“These agreements are integral to repowering our Gladstone aluminium operations with affordable, reliable and lower-carbon energy for decades to come,” Rio Tinto chief executive, Australia, Kellie Parker said.

“For the first time, we have integrated crucial battery storage in our efforts to make the Boyne aluminium smelter (pictured above) globally cost-competitive, as traditional energy sources become more expensive.

“We continue to investigate further renewable energy investments to repower our Gladstone aluminium operations.”

Edify Energy will build and operate the renewable energy projects, with construction due to begin in late 2025 and targeting completion in 2028.

The Smoky Creek and Guthrie’s Gap agreements help secure a total of 2.7GW of future wind and solar energy when combined with 2.2GW of power purchase agreements Rio Tinto announced for its Gladstone operations in 2024.

Together, the four contracted projects are expected to supply 80 per cent of Boyne smelter’s annual average electricity demand, reducing the smelter’s scope 1 and 2 emissions by 70 per cent.

This was the equivalent of removing about 2 million internal combustion engine cars from the road, Rio Tinto said.

Rio Tinto’s 90 per cent share of the Smoky Creek and Guthrie’s Gap battery system capacity amounts to 2,160MWh, which will provide about 30 per cent of the firming required to repower the Boyne smelter with renewable energy.

It will store green energy for reliable use during peak demand periods or low solar output, which will improve stability and resilience of Queensland’s power network.

Rio Tinto’s three production assets in the Gladstone region are the Boyne aluminium smelter, the Yarwun alumina refinery and the Queensland alumina refinery.