Electric vehicles can fight climate change, but they’re not a silver bullet: U of T study
University
of Toronto
It’s a massive change – but according to a group of researchers at the
University of Toronto’s Faculty of Applied Science & Engineering, it won’t
be nearly enough to address the global climate crisis.
“A
lot of people think that a large-scale shift to EVs will mostly solve our
climate problems in the passenger vehicle sector,” says Alexandre Milovanoff, a PhD
student and lead author of a new paper published in Nature Climate Change.
“I
think a better way to look at it is this: EVs are necessary, but on their own,
they are not sufficient.”
Around the world, many governments are already going all-in on EVs. In Norway, for example, where EVs already account for half of new vehicle sales, the government has said it plans to eliminate sales of new internal combustion vehicles by 2025. The Netherlands aims to follow suit by 2030, with France and Canada to follow by 2040. Just last week, California announced plans to ban sales of new internal combustion vehicles by 2035.
Milovanoff and
his supervisors in the department of civil and mineral
engineering – Assistant Professor Daniel Posen and Professor Heather MacLean – are experts in life cycle assessment,
which involves modelling the impacts of technological changes across a range of
environmental factors.
They
decided to run a detailed analysis of what a large-scale shift to EVs would
mean in terms of emissions and related impacts. As a test market,
they chose the United States, which is second only to China in terms of
passenger vehicle sales.
“We
picked the U.S. because they have large, heavy vehicles, as well as
high vehicle ownership per capita and high rate of travel per capita,”
says Milovanoff. “There is also lots of high-quality data available, so we
felt it would give us the clearest answers.”
The team
built computer models to estimate how many electric vehicles would be
needed to keep the increase in global average temperatures to less than 2 C
above pre-industrial levels by the year 2100, a target often cited by climate
researchers.
“We
came up with a novel method to convert this target into a carbon budget for
U.S. passenger vehicles, and then determined how many EVs would be needed
to stay within that budget,” says Posen. “It turns out to be a lot.”
Based
on the scenarios modelled by the team, the U.S. would need to have about 350
million EVs on the road by 2050 in order to meet the target emissions
reductions. That works out to about 90 per cent of the total vehicles
estimated to be in operation at that time.
“To
put that in perspective, right now the total proportion of EVs on the road in
the U.S. is about 0.3 per cent,” says Milovanoff.
“It’s
true that sales are growing fast, but even the most optimistic projections
suggest that by 2050, the U.S. fleet will only be at about 50 per
cent EVs.”
The
team says that, in addition to the barriers of consumer preferences for EV
deployment, there are technological barriers such as the strain that
EVs would place on the country’s electricity infrastructure.
According
to the paper, a fleet of 350 million EVs would increase annual electricity
demand by 1,730 terawatt hours, or about 41 per cent of current
levels. This would require massive investment in infrastructure
and new power plants, some of which would almost certainly run on fossil
fuels.
The
shift could also impact what’s known as the demand curve – the
way that demand for electricity rises and falls at different times of
day – which would make managing the national electrical grid more complex.
Finally, there are technical challenges stemming from the supply of critical
materials for batteries, including lithium, cobalt and manganese.
The
team concludes that getting to 90 per cent EV ownership by 2050 is an
unrealistic scenario. Instead, what they recommend is a mix of policies,
including many designed to shift people out of personal passenger vehicles in
favour of other modes of transportation.
These
could include massive investment in public transit – subways, commuter trains,
buses – as well as the redesign of cities to allow for more trips to be taken
via active modes such as bicycles or on foot. They could also include
strategies such as telecommuting, a shift already spotlighted by the COVID-19
pandemic.
“EVs
really do reduce emissions, but they don’t get us out of having to do the
things we already know we need to do,” says MacLean. “We need to rethink our
behaviours, the design of our cities, and even aspects of our culture.
Everybody has to take responsibility for this.”
The
research received support from the Hatch Graduate Scholarship for Sustainable
Energy Research and the Natural Sciences and Engineering Research Council
of Canada.