A comparative life cycle assessment of magnesium and aluminum transmission system

Abstract

This study assesses the life-cycle environmental impacts of magnesium (Mg) and aluminum (Alu) in automotive transmission systems, with emphasis on energy consumption, greenhouse gas (GHG) emissions, and trade-offs between production and use phases. The study employs Life Cycle Assessment (LCA) based on ISO 14040/14044 standards and iterative analysis through the GREET model covering material extraction, production processes, use phase and end-of-life processes. Results show that due to its lightweight property, Mg provides a significant benefit during the use phase, with total energy consumption for Mg transmissions being 16.6–17.4% lower than for Alu systems. The emissions in the use phase of Mg are also lower, with a decrease in CO₂ emissions of 23.6%, compensating for its higher production-phase emissions. Mg shows better performances in some emissions categories, such as a 74% reduction in SOₓ emissions compared to Alu. While the GHG emissions during production of Mg are higher, advancements in Mg manufacturing technologies such as cleaner electrolytic processes and alternative cover gases may reduce the environmental impact in the future. The results highlight Mg's potential to replace Alu as the primary material in automotive transmission systems, especially as production advances continue to improve. Based on Mg's higher use-phase performance and the continuous development of Mg technologies, the results of the study confirm that, compared to Alu, Mg can be considered as a promising and sustainable alternative, which may lead to Mg potential becoming one of the primary materials across multiple sectors within the next decade.