Different technology packages for aluminium smelters worldwide to deliver the 1.5 °C target

Abstract

Production of aluminium, one of the most energy-intensive metals, is challenging for mitigation efforts. Regional mitigation strategies often neglect the emissions patterns of individual smelters and fail to guide aluminium producers’ efforts to reduce GHG emissions. Here we build a global aluminium GHG emissions inventory (CEADs-AGE), which includes 249 aluminium smelters, representing 98% of global primary aluminium production and 280 associated fossil fuel-based captive power units. We find, despite the installation of more efficient and higher amperage cells, that the share of aluminium production powered by fossil fuel-based captive power units increased from 37% to 49% between 2012 and 2021. Retiring fossil fuel-based captive power plants 10 years ahead of schedule could reduce emissions intensity by 5.0–10.5 tCO2e per tonne of aluminium for dependent smelters. At least 18% of smelting capacity by 2040 and 67% by 2050 must be retrofitted with inert anode technology to achieve net-zero targets. The aluminium production process is energy intensive and individual smelters often depend on associated fossil fuel-based captive power units. With detailed global facility-level data, this research highlights the importance of early retirement of fossil fuel plants and retrofitting with inert anodes.