Electric vehicles (EVs) 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 concerns 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 EVs. We develop and provide a transparent life cycle inventory of conventional and electric vehicles and apply our inventory to assess conventional and EVs over a range of
impact categories.We find that EVs 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, EVs 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 EVs than conventional vehicles, assuming a vehicle lifetime of 200,000 km
exaggerates the GWP benefits of EVs to 27% to 29% relative to gasoline vehicles or 17%
to 20% relative to diesel. An assumption of 100,000 km decreases the benefit of EVs to 9%
to 14% with respect to gasoline vehicles and results in impacts indistinguishable from those
of a diesel vehicle. Improving the environmental profile of EVs requires engagement around reducing vehicle production supply chain impacts and promoting clean electricity sources in
decision making regarding electricity infrastructure.