Multiple pathways to transport decarbonisation: bioethanol and electrification across distinct energy systems

Transport decarbonisation is critical to achieving net-zero mobility, yet mitigation pathways vary globally. This study presents a regionalised life-cycle assessment using the Greenhouse gases, Regulated Emissions, and Energy use in Technologies (GREET) model to investigate how contrasting energy systems influence environmental performance across Southern Brazil, the United Kingdom (UK), and the United States of America (USA) Midwest over a 200,000 km vehicle lifetime. Results show that decarbonisation pathways cannot be universally prioritised and must align with regional grid characteristics. Compared with gasoline internal combustion engine vehicles, battery electric vehicles reduce greenhouse gas emissions by 47–70%, depending on the energy system. However, ethanol-fuelled vehicles in Brazil achieve emissions comparable to electric vehicles operating in fossil-intensive grids, highlighting low-carbon biofuels as a strong regional alternative. The proposed framework provides vital decision-support insights for designing context-specific transport policies based on regional fuel production.