Life cycle assessment of electric vehicles and buses in Brazil: effects of local manufacturing, mass reduction, and energy consumption evolution

Abstract

Environmental impacts of battery electric vehicles (BEVs) and internal combustion engine vehicles have been broadly studied and compared. However, there is scarce evidence of studies analyzing the potential effect of evolution key factors. The purpose of this study was to evaluate what would be the environmental impact of manufacturing BEVs and battery electric buses (BEBs) in Brazilian southeast, whereas vehicle mass reduction, material switching, energy consumption, battery improving, geographic adaptation of life cycle inventories, and electricity mix evolution effects are considered. The methodology was based on adapting a representative number of global Ecoinvent V.3.2 datasets to better represent local conditions and subsequently to include evolution parameters for a 2030 scenario. Thus, we were able to establish a comparison for BEVs and BEBs in 2015 and 2030 for Brazilian and global conditions. This study compared BEV and BEB production (one vehicle as comparison unit) and also well-to-wheel (WTW) stage (1 km as functional unit). The research envisioned mass reduction configurations for cars and buses in 2030. BEV analysis in 2030 includes two material switching scenarios: plastic and aluminum prototypes. For one BEV as comparison unit, ozone depletion, human toxicity, metal depletion, and ecotoxicities displayed larger impacts for Brazilian cars, mostly due to material switching in the new prototypes, in spite of total mass reduction. In fact, neither the BEBs nor BEVs made in Brazil displayed a consistent environmental advantage over the global reference; and in fact, low production plants might cause larger impacts. Life expectancy increase is suggested to be more effective in reducing impacts than mass or energy consumption reduction. For the 2030 BEV, an unexpected burden shifting result appears. Ozone depletion increases for the Brazilian aluminum prototype since emissions arising from scrap treatment do have a significant impact, even though mass reduction was considered. Bus results portrayed a tendency for Brazilian bus to perform better than its global counterpart except for metal depletion, ecotoxicities, and ozone depletion. A large environmental contribution from treatment of mining residues is common for human toxicity and freshwater eutrophication, the most concerning categories. Large contributions from mining residues led us to conclude that in order to manufacture environmentally competitive BEBs and BEVs, either reduction of impacts on metal extraction, e.g., copper, magnesium, etc., or metal use decrease must be prioritized. Negative consequences of vehicle evolution are especially concerning for human health and bodies of water, and impact decrease will be unlikely, at least until 2030.