Electric vs. Plug-In Hybrid Cars: Which Is Greener?
Depending on the driving you do, a plug-in hybrid electric vehicle (PHEV) can be more
environmentally friendly than a gasoline-powered vehicle and sometimes more than a battery
electric vehicle (BEV or just EV). But the reverse is also true—in most instances,
a plug-in hybrid is less environmentally friendly than an EV, and in many instances, worse than
the gasoline vehicles it was meant to replace. In the coming years, there will be less and
less of an incentive to buy a PHEV for either its convenience or its price.
Charging Convenience One of the main reasons people choose plug-in
hybrids over EVs is the fact that hybrids usually have a greater range. Potential buyers
may want to reduce their carbon footprint, but they also want the convenience of being
able to easily refuel their vehicle on a road trip.
Currently, charging infrastructure for electric vehicles can be spotty, leaving potential
EV drivers with worries that they won't be able to get from Point A to Point B. While
Tesla has installed a network of over 1,000 Supercharger locations in the United States
and over 25,000 stations worldwide, currently only Tesla vehicles can use them.
That situation is soon about to change, however. CEO Elon Musk recently announced that Tesla
will gradually open up its network to other vehicles in 2021, and the U.S. government
has plans to rapidly install an EV charging network of 500,000 charging stations. With
the political will, this can be done quickly: In the month of December 2020, China installed
112,000 EV charging stations, more than existed in the entire United States at the time.
What About Plug-Less Hybrids? This article does not consider plug-less hybrid
electric vehicles (HEVs). While they have greater fuel efficiency and produce fewer
greenhouse gas emissions than conventional gasoline-powered vehicles, they are essentially
that: more efficient gasoline-powered vehicles, since their batteries cannot be charged from
an electric outlet. The case for the environmental superiority
of electric vehicles over all gasoline-powered vehicles is quite clear. Over the entire life
cycle of a vehicle, from raw materials to final disposal, driving an EV produces fewer
pollutants and less greenhouse gas emissions than a comparable gasoline vehicle. Only in
a few regions around the world today, in places where the vast majority of electricity is
generated by coal, do HEVs produce fewer lifetime emissions than EVs, but this applies to no
more than 5% of the world's transport. Environmental Benefits
Under almost all circumstances, driving an electric vehicle is more environmentally beneficial
than driving a plug-in hybrid. While electric vehicles provide the highest co-benefits of
any vehicles in reducing air pollution and greenhouse gas emissions across the United
States, in specific regions PHEVs provide greater environmental benefits than both gas-powered
and electric vehicles. This depends on two main factors: the amount
of fossil fuel burned in order to produce the electricity that charges EVs, and the
type of driving that a PHEV owner does. In short, the dirtier the electricity, the less
environmental advantage electricity has over gasoline, or as one study stated (in the inverse):
“the more the electricity sector is decarbonized, the greater the benefit of electrifying passenger
vehicles.” Driving habits also matter: the batteries
of 2021 model plug-in hybrids have an average range of 29 miles, according to the U.S. EPA's
Fuel Economy Guide Model Year 2021. Run the battery down, or run it at high speeds, and
a PHEV runs on gasoline—and its emissions increase correspondingly.
A 2020 study from the International Council on Clean Transportation (ICCT) found that
the majority of miles driven in a PHEV is not city driving but “extra-urban driving,”
where the gasoline engine is more often used. Moreover, the same study found that PHEV owners
do not charge their vehicles often enough to take advantage of their greater fuel efficiency.
As a result, in real-world driving, PHEVs' electric motors are used for only half the
amount of time that they are assumed to run. Their CO2 emissions are thus two to four times
higher than they are approved for by regulators. A separate 2020 study from Transport & Environment,
finding similar disparities, also determined that because PHEVs are heavier than gasoline
cars, they consume more fuel. Julia Poliscanova, a researcher at Transport & Environment, concluded
that "from the perspective of environment and climate, today's plug-in hybrid technology
is worse than what it is replacing." The dilemma for potential plug-in hybrid buyers
is that they want to reduce their carbon footprint while retaining the ability to drive longer
distances than an EV allows on a single charge. But it's precisely long-distance driving that
reduces the environmental benefits of plug-in hybrids.
Financial Considerations In making “green” purchasing decisions,
people also frequently have to weigh the environmental benefits against the potentially higher financial
costs. The more expensive the purchase, the more those financial concerns can win out
over environmental ones. So if EVs are greener, do they come at a higher
financial cost? Depending on the use case, a plug-in hybrid can be more economical to
own than an electric vehicle, or vice versa. That is likely to change in the future since
the current reasons for preferring a PHEV are areas where EVs are improving the fastest.
According to a 2021 study from the U.S. Department of Energy's Argonne National Laboratory, maintenance
costs of an electric vehicle are lower than a plug-in hybrid: $0.061 per mile for an EV
versus $0.090 for a PHEV, the latter being closer in price to vehicle solely powered
by gasoline (at $0.101) than to an EV—which makes sense, considering that PHEVs still
have internal combustion engines and battery technology that need to be maintained. The
study also determined that an EV had on average better fuel economy than a PHEV: the equivalent
of 91.9 miles per gallon for an EV compared to 62.96 mpg for a PHEV. Yet because of the
higher purchasing cost of EVs, due largely to the price of their batteries, the study
concluded that PHEVs on average have a lower total cost of ownership than electric vehicles.
Once again, however, much of this depends on driving habits. As noted, PHEVs are driven
on gasoline in real-world studies far more often than has been previously estimated.
This increases their fuel costs, which are already more than double those of an EV. According
to the EPA's Fuel Economy Guide Model Year 2021, the average annual estimated fuel cost
of a 2021-model EV was $667.50, while that of a PHEV was $1,481.73. (By comparison, a
2021-model gasoline car owner spends an average of $2,077.02 per year on fuel.)
Electricity is also far cheaper than gasoline. In August 2021, the average price of a gallon
of gas was $3.18, while the price of an equivalent amount of electricity was $1.16. And as the
ICCT study cited above observed, PHEV's “real fuel consumption is two to three times higher
than the test-cycle values.” The EPA's average annual fuel costs for PHEVs may be under-estimated.
Outlook for the Future Colin McKerracher, the lead author of Bloomberg
New Energy Finance (BNEF)'s Electric Vehicle Outlook 2021 states that plug-in hybrids “more
and more look like a compliance strategy” which has allowed automakers to comply with
emissions standards set by the European Union. As electric vehicles increasingly become the
focus of auto manufacturers and as emissions standards are toughened, PHEVs could be phased
out as too expensive and unable to compete with cleaner and lower-cost EVs. Because they
have two fuel sources and two modes of propulsion, they “can never be cheaper on an upfront
basis” than gasoline vehicles, and can never proportionally profit as much from the continued
drop in lithium-ion battery prices as EVs can.
Once electric vehicles reach price parity with both PHEVs and fossil fuel vehicles,
and once EV charging infrastructure is built out enough to make car buyers comfortable,
it is likely that PHEVs will increasingly appear as a necessary but transitory shift
to a cleaner, greener driving technology. Some automakers have already seen the writing
on the showroom walls. In 2019, facing declining sales in PHEVs, Volkswagen and General Motors
announced plans to cut their development of PHEVs and turned their attention to EVs. In
2021, Ford announced that it would sell only EVs and PHEVs (in Europe) by 2026, and phase
out PHEVs by 2030. It seems increasingly clear that the future
of transportation is fully electric. In the most mature electric vehicle markets, such
as California and Norway, where robust charging networks and government incentives exist,
that future is already here. How soon that future comes to you may depend on where you
live.