UK-Australian mining firm Rio Tinto plans to significantly reduce operating carbon dioxide (CO2) emissions from its aluminium projects in Queensland's Gladstone through renewable electricity supplies from Australia's largest planned solar photovoltaic (PV) plant.
A 25-year power purchase agreement (PPA) signed with Danish renewable energy firm European Energy's Australian subsidiary has Rio Tinto buying all the output from the 1.1GW Upper Calliope solar PV project, which could come on line around 2026-27. Construction work will take approximately two years once it starts in 2025 or 2026 some 50km southwest of Gladstone, pending development and grid connection approvals, Rio Tinto said on 24 January. Average output could reach 2.8 TWh/yr, according to European Energy Australia.
The PPA will represent around a quarter of the total 4GW of solar and wind capacity that Rio Tinto needs to power its Boyne aluminium smelter and the Yarwun and Queensland alumina refineries, all located in Gladstone. The entire operation requires more than 1GW of base-load generation capacity, which could increase in the future with potential further electrification of plant processes.
Upper Calliope is the first successful applicant in a formal request for proposals made by Rio Tinto in mid-2022. The solar PV plant could have the potential to lower Rio Tinto's operating CO2 emissions by 1.8mn t/yr, helping its goal of halving its global scope 1 and 2 greenhouse gas (GHG) emissions by 2030 from 2018 levels.
It last year signed an agreement with Japanese trading house Sumitomo to build a hydrogen plant at Yarwun to cut CO2 emissions in the refining process.
The mining firm reported 142 petajoules (PJ) of global renewable energy use in 2022, the lowest in at least five years, while non-renewable energy use rose to the highest over that period at 254PJ. Its global scope 1 and 2 emissions fell to 30.3mn t CO2 equivalent (CO2e) in 2022 from 31mn t CO2e in 2021 and 33.7mn t CO2e in 2018. The aluminium business represented the highest volume in 2022 at 21.1mn t CO2e, while Australia overall made 18.2mn t CO2e of the total.
Rio Tinto said last year that it planned to build a long-term carbon credit portfolio globally generating around 1.7mn t/yr by 2030, focusing on regions where its scope 1 and 2 emissions are highest, such as Australia and North America. "Our preference is to have deeper involvement with a smaller number of projects to ensure that we are retiring high-integrity carbon credits," it said in its latest climate change report.
The company's alumina and aluminium production last year was in line with its production guidance, with aluminium output rising by 9pc from a year earlier to nearly 3.3mn t.
