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Rarely do our scientific publications
spark widespread media attention
like the electric vehicle study by Troy
Hawkins, Bhawna Singh, Guillaume
Majeau-Bettez, and Anders Hammer
Strømman. The BBC and the Guardian
picked up this study in Oct. 2012, which
then spread to news sources and blogs
around the world. It was even cited in a
popular article in the Wall Street Jour-
nal by Bjorn Lomborg. All of this media
attention sparked a polarized debate
about the environmental impacts of
electric vehicles in the general public.
To date, there have been 228 comments
on the BBC article, 379 comments on the
Guardian article, and 973 comments on
the Wall Street Journal article. This pa-
per clearly touched on a key question
of great public interest - how green are
electric vehicles compared to conven-
tional vehicles? Electric vehicles coupled
with low-carbon electricity sources offer
the potential for reducing greenhouse
gas emissions and exposure to tailpipe
emissions from personal transporta-
tion. Given the zero tailpipe emissions,
electric vehicles are often seen as envi-
ronmentally friendly, but what about the
higher manufacturing impacts of bat-
teries for electric vehicles? While many
studies have focused on the use phase
emissions in comparing transportation
options, vehicle production is also sig-
nificant when comparing conventional
and electric vehicles. Therefore, a life-
cycle perspective is needed to address
concerns of problem shifting.
This publication looked at the environ-
mental impacts of conventional and
electric vehicles over the entire lifecycle,
including the manufacturing, operation,
and end of life impacts. A transparent life
cycle inventory of conventional and elec-
tric vehicles was developed and used to
compare the environmental perform-
ance over a range of impact categories.
Findings showed that electric vehicles
powered by the present European elec-
tricity mix offer a 10% to 24% decrease in
global warming potential (GWP) relative
to conventional diesel or gasoline vehi-
cles assuming lifetimes of 150,000 km.
However, electric vehicles exhibit the po-
tential for significant increases in human
toxicity, freshwater eco-toxicity, freshwa-
ter eutrophication, and metal depletion
impacts, largely coming from the vehicle
supply chain. Results are sensitive to as-
sumptions regarding electricity source,
use phase energy consumption, vehicle
lifetime, and battery replacement sched-
ules. Because production impacts are
more significant for electric vehicles
than conventional vehicles, assuming a
vehicle lifetime of 200,000 km exagger-
ates the GWP benefits of electric vehi-
cles 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 electric vehicles to 9% to
14% with respect to gasoline vehicles
and results in impacts indistinguishable
from those of a diesel vehicle. Improv-
ing the environmental profile of electric
vehicles, the study concludes, requires
engagement around reducing vehicle
production supply chain impacts and
promoting clean electricity sources in
decision making regarding electricity in-
frastructure.
While this study aimed to provide a fair
and balanced view on the environmen-
tal performance electric vehicles, these
results stirred quite a polarized response
from around the world. Both supporters
and critics of electric vehicles weighed
in on the debate, showing that our sci-
entific research within Industrial Ecology
can in fact spark public dialogue over
key environmental topics. Our research
can provide a strong scientific basis that
leads to more informed discussions re-
garding how we tackle environmental
challenges.
Contact person:
Professor Anders Hammer Strømman
anders.hammer.stromman@ntnu.no
Comparative Environmental Life Cycle Assessment of Conventional and
Electric Vehicles
RESEARCH