Uncertain Environmental Footprint of Current and Future Battery Electric Vehicles

The
future environmental impacts of battery electric vehicles (EVs)
are very important given their expected dominance in future transport
systems. Previous studies have shown these impacts to be highly uncertain,
though a detailed treatment of this uncertainty is still lacking.
We help to fill this gap by using Monte Carlo and global sensitivity
analysis to quantify parametric uncertainty and also consider two
additional factors that have not yet been addressed in the field.
First, we include changes to driving patterns due to the introduction
of autonomous and connected vehicles. Second, we deeply integrate
scenario results from the IMAGE integrated assessment model into our
life cycle database to include the impacts of changes to the electricity
sector on the environmental burdens of producing and recharging future
EVs. Future EVs are expected to have 45–78% lower climate change
impacts than current EVs. Electricity used for charging is the largest
source of variability in results, though vehicle size, lifetime, driving
patterns, and battery size also strongly contribute to variability.
We also show that it is imperative to consider changes to the electricity
sector when calculating upstream impacts of EVs, as without this,
results could be overestimated by up to 75%.