Aluminium production, one of the most energy-intensive metal industries, poses a nerve-wracking challenge for global mitigation efforts. A recent study published by Nature sheds light on the evolving dynamics of greenhouse gas (GHG) emissions in the aluminium sector and highlights the urgent need for innovative technologies and policy interventions to achieve net-zero goals.
Despite advancements in technology, such as the adoption of more efficient and higher amperage cells, the proportion of aluminium production powered by fossil fuel-based captive power units rose from 37 per cent in 2012 to 49 per cent in 2021. The study reveals that retiring these power plants ten years ahead of schedule could reduce emissions intensity by 5.0–10.5 tonnes of CO2 equivalent (tCO2e) per tonne of aluminium for smelters dependent on such energy sources. Furthermore, achieving net-zero targets necessitates retrofitting at least 18 per cent of smelting capacity with inert anode technology by 2040, increasing to 67 per cent by 2050.
Encouragingly, the industry has reached a pivotal moment. In 2023, while global aluminium production grew by 2.75 per cent, GHG emissions increased by a mere 0.36 per cent. This decoupling of production growth from emissions growth marks a significant milestone. The emissions intensity of aluminium production dropped by 2.33 per cent in 2023 and has declined by 11.5 per cent since 2020.
Miles Prosser, Secretary General of the International Aluminium Institute (IAI), remarked, "The latest data reinforces our confidence that the industry has reached a turning point, with metal production growth successfully decoupled from emissions growth. We are encouraged to see that the initiatives undertaken by IAI's member companies are enabling increased production without a significant rise in greenhouse gas (GHG) emissions."
"However, while the stable emissions levels in 2023 reflect positive progress, they also serve as a stark reminder of the scale of the challenge ahead in reducing emissions. The industry's sustained efforts and substantial investments in emissions-reduction projects have laid a strong foundation, but more must be done. As an industry, we must find ways to deliver emissions reductions faster, deeper and broader across the industry," he added.
Aluminium's carbon footprint: A breakdown
In 2023, the global aluminium value chain—encompassing mining, refining, smelting, and recycling—emitted 1,116 million tonnes of CO2 equivalent. Among these, electrolysis emerged as the largest contributor, responsible for 791 million tonnes of CO2e. This was driven by indirect electricity use (609 million tonnes) and direct process emissions (107 million tonnes). Refining accounted for 166 million tonnes, primarily from thermal energy consumption, while mining had a smaller footprint of 5.3 million tonnes. Recycling and semis production collectively emitted 61 million tonnes.
Electricity usage dominated overall emissions, contributing 652.7 million tonnes, followed by thermal energy (170.5 million tonnes) and direct process emissions (115 million tonnes). These figures underscore the pressing need for the aluminium industry to transition to low-carbon electricity sources and adopt near-zero GHG emission technologies.
Technology: A beacon of hope
The study underscores the transformative potential of advanced technology packages in reducing emissions. Innovations such as inert anode technology, which eliminates direct CO2 emissions during the smelting process, and enhanced energy efficiency systems can significantly lower energy consumption. The adoption of cleaner energy sources—including hydropower, solar, and wind—further complements these efforts, offering a pathway to revolutionise the industry's environmental impact.
Various technologies and strategies are in place at reducing energy consumption and emissions in aluminium production. The main areas of focus include improving thermal balance, retrofitting electrodes, implementing intelligent control systems, developing new build facilities, and utilising cleaner electricity sources. Each of these categories includes multiple technologies that contribute to energy efficiency and emission reductions.
Quantitative data highlights the benefits of specific technologies. For instance, better insulation can save 0.2–0.7 kWh per kilogram of aluminium while limiting air burn reduces emissions by approximately 5.5 per cent. The readiness levels of these technologies, however, vary widely. Some are already commercialised, while others are in demonstration (targeted for 2025), development (2030), or prototype stages (beyond 2035). This staggered timeline necessitates strategic planning to ensure timely deployment.
The road ahead: Policies and investments
The study calls for targeted policies and substantial investments to accelerate the adoption of cleaner technologies. Policymakers are urged to design regulatory frameworks and incentive structures that promote innovation and ensure equitable access to advanced technologies, especially for smelters in economically disadvantaged regions. Financial institutions and industry stakeholders must prioritise funding mechanisms that support this transition.
As a trade-exposed sector, responsible aluminium production requires access to fair global markets for both inputs and outputs. Moreover, as aluminium is a critical material for clean energy technologies, achieving a low-carbon circular economy hinges on secure and resilient aluminium supply chains.
The aluminium industry stands at a crossroads. While significant progress has been made in decoupling production growth from emissions growth, the path to net zero requires intensified efforts. Advanced technologies, cleaner energy sources, and robust policy support are vital for the sector to meet its sustainability goals. By embracing these changes, the aluminium industry can not only reduce its environmental impact but also solidify its role as a cornerstone of a low-carbon future.
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