Electric vehicles (EVs) are a cleaner alternative to gasoline- or diesel-powered cars and trucks—both in terms of harmful air pollution, and the greenhouse gas emissions that are causing climate change.
Most cars and trucks use an “internal combustion engine” (ICE), powered by burning oil-based fuels. When burned, those fuels create climate-warming carbon dioxide (CO2) and other pollutants the vehicles release from their tailpipes.
Electric vehicles have neither engines nor tailpipes. Instead, they have batteries that power electric motors. It’s the same setup as a remote-controlled toy car, although a great deal of hard engineering has gone into making this work with a heavy, human-scaled vehicle that runs for hundreds of miles on a single charge.
Challenges to electric vehicle adoption
Cars and trucks produce a fifth of all climate pollution in the U.S.(1) And because new cars normally stay on the road for 15 to 20 years, much of that pollution is already “locked in” into the 2040s. If electric vehicles are going to change the way we travel in time to meet our climate goals, people need to start choosing them over ICE cars today.
In many ways, EVs are already an attractive purchase. They’re fast, quiet, don’t need much maintenance, and because it’s cheaper to charge their batteries with electricity than to buy gasoline, the “total cost of ownership” of EVs is very competitive.
Still, EVs tend to cost more upfront than comparable ICE cars, which is a key consideration for many car buyers, and additional cost is required to install a dedicated EV charger at home. To solve this problem, governments can subsidize EVs. In the U.S., buyers can claim tax credits up to $7,500 for buying a new EV (2), and many states offer more.
In addition to cost, EVs must meet drivers’ expectations. Most drivers buy cars not just because they’re good enough for daily travel, but also to meet the demands of their longest trips. Only recently have EV batteries become good enough to drive 300+ miles, or to provide reliable charges for heavy vehicles like pickup trucks and buses. For the heaviest vehicles, like long-distance freight trucks and construction vehicles, EVs still lag in performance. And a larger system of EV charging stations is needed to match the U.S. network of over 100,000 gas stations.
Just how clean are electric vehicles?
Electric vehicles are unambiguously better for the climate than ICE cars. But they do create some pollution.
That’s because the electricity that powers EVs has to come from somewhere: often, a fossil fuel power plant. Luckily, power plants are much more efficient at making energy than a car engine, so even an EV that runs entirely on electricity from coal—the very “dirtiest” fossil fuel—will still produce less CO2 per mile driven than a similar ICE car (3).
In practice, most electric grids have a mix of fossil fuels and clean energy. An electric car charged on the average U.S. electric grid creates just a third as much CO2 per mile as a similar ICE car: the equivalent of a gasoline car that gets over 100 miles per gallon (4). And as the grid itself improves, EVs already on the road will continue to get cleaner.
Manufacturing EV batteries, and mining and refining the minerals used in them, also creates climate pollution. An EV rolling off the factory floor has likely produced 50% to 80% more CO2 than a similar ICE vehicle before it drives a single mile (5). The EV then “pays off” these manufacturing emissions by driving cleaner over a lifetime of use (6).
All this means that, while EVs can help lower our greenhouse gas emissions by replacing ICE vehicles, they are not perfect. EVs are best seen as part of a suite of tools for clean transportation. Where practical, walking, biking, or using public transportation will almost always create less CO2 than EVs, while EVs have a unique role serving longer trips and those that can only be taken by car.
Electric vs. hybrid vehicles
A fully electric vehicle, or “battery electric vehicle” (BEV), is quite different from a “hybrid electric vehicle” (HEV). The hybrid has a normal internal combustion engine, but also has an electric motor and battery that can capture energy that would otherwise be lost during braking. Using both the engine and its electric motor to turn its wheels, an HEV can get by on much less fuel than a standard ICE car, but ultimately all its energy comes from oil.
In between a hybrid and BEV is a “plug-in hybrid electric vehicle” (PHEV). This still has an engine, but also has a mid-sized battery that can be charged directly and power the car on its own. A PHEV acts like a fully electric vehicle on smaller journeys, only burning fuel on longer trips that exceed the range of its battery.
Published July 24, 2023.
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International license (CC BY-NC-SA 4.0).
Photo Credit: JUICE via Unsplash
FOOTNOTES
1 Congressional Budget Office: Emissions of carbon dioxide in the transportation sector. December 2022.
2 U.S. Department of Energy: Fuel Economy: Tax Incentives.
3 Reuters: "Analysis: When do electric vehicles become cleaner than gasoline cars?" Paul Lienert, July 7, 2021. Analysis based on Argonne National Laboratory's GREET (Greenhouse gases, Regulated Emissions, and Energy use in Technologies) Model, sponsored by the U.S. Department of Energy.
4 MIT Energy Initiative: Insights Into Future Mobility, November 2019.
5 In the Insights Into Future Mobility study cited above, the Honda Clarity battery electric vehicle is concluded to produce 57.5% more manufacturing emissions than the comparably Toyota Camry ICE vehicle. In the GREET model also cited above, an EV with a 300-mile battery range is concluded to produce 80% more manufacturing emissions than a comparable ICE vehicle. For more information, see, “How much CO2 is emitted by manufacturing batteries?”
6 For a more detailed analysis, see, “Are electric cars definitely better for the climate than gas-powered cars?”