Environment

Electric vehicles (EV’s) coupled with low-carbon electricity sources offer the potential for reducing greenhouse gas emissions and exposure to tailpipe emissions from personal transportation. In considering these benefits, it is important to address the phenomenon  of problem- shifting. In addition, while many studies have focused on the use phase in comparing transportation options, vehicle production is also significant when comparing conventional and EV’s. We have developed and provided a transparent life cycle inventory of conventional and electric vehicles and apply our inventory to assess conventional and EV’s over a range of impact categories. We find that EV’s powered by the present European electricity mix offer a 10% to 24% decrease in global warming potential (GWP) relative to conventional diesel or gasoline vehicles assuming lifetimes of 150,000 km. However, EV’s exhibit the potential for significant increases in human toxicity, freshwater eco-toxicity, freshwater eutrophication, and metal depletion impacts, largely emanating from the vehicle supply chain. Results are sensitive to assumptions regarding electricity source, use phase energy consumption, vehicle lifetime, and battery replacement schedules. Because production impacts are more significant for EV’s than for conventional vehicles, assuming a vehicle lifetime of 200,000 km exaggerates the GWP benefits of EV’s from 27% to 29% relative to gasoline vehicles from 17% to 20% relative to diesel vehicles. An assumption of 100,000 km decreases the benefit of EV’s from 9% to 14% with respect to gasoline vehicles and results in impacts indistinguishable from those of a diesel vehicle. Improving the environmental profile of EV’s requires engagement around reducing vehicle production supply chain impacts and promoting clean electricity sources in decision making regarding electricity infrastructure.