Does the electric vehicle promotion policy drive Thailand's passenger transport towards environmental sustainability?

Electric vehicles (EVs) are considered an alternative to internal combustion engine vehicles (ICEVs) for promoting sustainable transport, with environmental benefits depending on many local factors. This study performed a comprehensive life cycle assessment of passenger transport in major urban areas of Thailand, encompassing on-road, metro trains, and inland water transport, to determine the benefits of EV deployment. The findings showed that the vehicle life cycle (manufacture, maintenance, and disposal) was a significant contributor to human health and ecosystem quality impacts when comparing across transport life cycle phases in both ICEVs and EVs. Among private vehicles, with the current electricity mix, EVs had impacts on human health and ecosystem quality comparable to small-size ICEVs. At the projected 2037 electricity mix, the EVs will have lower impacts on human health, ecosystem quality and resource scarcity in comparison with the ICEVs. In scenario analysis, when considering only on-site emissions, it was found that private EV promotion had an environmental cost by about 16-43 % lower than the business-as-usual (BAU) scenario, depending on the rate of EV adoption, while shifting to public electric buses or metro trains had a lower environmental cost by 21 % and 23 % compared to BAU, respectively. If assessing the full transport life cycle, shifting to public electric buses or metro trains had a lower environmental cost (22-23 %) than the promotion of EVs with current electricity mix (14 %). The effectiveness of environmental impact mitigation through deployment of private EVs might increase to a comparable level with public electric bus or metro train shifts when Thailand achieves the electricity mix target with 34 % of renewable energy in 2037.