Significance Statement
The energy and environmental benefits of vehicle lightweighting had been the object of many pre-existing studies. However, a lack of methodological consistency among such literature sources – in term of system boundaries, key assumptions and impact metrics – often led to inconclusive and potentially misleading comparisons.
This new paper is thus extremely relevant in addressing this issue by presenting a fully consistent life cycle assessment of a wide range of lightweighting strategies for compact vehicles, and also taking into account alternative end-of-life treatment scenarios.
Results have shown that the use of aluminium alloys for body and chassis parts leads to the most robust improvements in environmental performance, considering a full range of impact metrics.
At the same time, though, the maximum achievable improvements are still small in absolute terms, thereby indicating that it is unreasonable to expect lightweighting alone to be effective in ‘cleaning up’ the automotive sector.
Journal Reference
Journal of Cleaner Production, Volume 108, Part A, 1 December 2015, Pages 1168–1176.
Marco Raugei, Denise Morrey, Allan Hutchinson, Patricia Winfield
Faculty of Technology, Design and Environment, Oxford Brookes University, Wheatley Campus, Wheatley OX33 1HX, UK
Abstract
A complete and fully consistent LCA-based comparison of a range of lightweighting options for compact passenger vehicles is presented and discussed, using advanced lightweight materials (Al, Mg and carbon fibre composites), and including all life cycle stages and a number of alternative end-of-life scenarios. Results underline the importance of expanding the analysis beyond the use phase, and point to maximum achievable reductions of environmental impact of approximately 7% in most impact categories. In particular, lightweighting strategies based on the use of aluminium were found to be the most robust and consistent in terms of reducing the environmental impacts (with the notable exception of a relatively high potential toxicity). The benefits of using magnesium instead appear to be less clear-cut, and strongly depend on achieving the complete phase-out of SF6 in the metal production process, as well as the establishment of a separate closed-loop recycling scheme. Finally, the use of carbon fibre composites leads to similar environmental benefits to those achieved by using Al, albeit generally at a higher economic cost.
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