New lines of electric trucks and SUVs hit the roads. Automakers are marketing vehicles like the Cybertruck Tesla, Ford’s F-150 Lightning, Rivian’s R1T, and GMC’s Hummer EV to customers who prefer to drive larger vehicles, regardless of their fuel efficiency. These new electric vehicles promise drivers the same heavy-duty performance as a combustion engine without burning a drop of oil, with marketing materials featuring horsepower, torque and acceleration of “watts of freedom.”
But as electric vehicles increase in size, they consume more energy — and indirectly, generate more carbon emissions. Electric vehicles charge their batteries by connecting them to power grids, which generate most of the electricity by burning fossil fuels: coal, oil and natural gas account for nearly two-thirds of global electricity production. Until electric utilities transition from fossil fuels to renewables like wind and solar — which, even under ambitious goals, won’t happen until 2030 — more extreme electric vehicles will generate carbon emissions that rival some hybrid and gas-powered vehicles.
But even these inefficient electric vehicles could play a role in cutting carbon emissions, if they could convince the people who drive gas-guzzling cars and trucks to switch to electric.
Comparing the emissions of electric vehicles to gas-powered cars
For decades, regulators have assigned gas and hybrid cars a mile-per-gallon (MPG) rating, which measures a vehicle’s fuel efficiency by measuring the number of miles it can drive on one gallon of gas. Regulators give EVs a rating similar to “miles per gallon equivalent” (MPGe), which measures the distance an EV can drive at 33.7 kWh of electricity (roughly the same energy content as a gallon of gas).
An electric Hummer, for example, has an efficiency rating of 47 mpg. That’s better than the best-selling gas-powered car on the market, the Toyota Corolla, which gets 30 mpg. But it’s nearly three times less efficient than the best-selling electric vehicle on the market, the Tesla Model Y, which gets 125 mega-pixels.
Miles per gallon is a constant measure of a car’s carbon emissions. Burning a gallon of gasoline will always release about 8,887 grams of carbon dioxide, according to the U.S. Environmental Protection Agency. So, the Ford F-150 will emit about 444 grams of CO2 on average for every mile you drive, no matter where it is located.
But the MPGe is a murkier measure of a car’s carbon footprint, because generating a kilowatt-hour of electricity will create different levels of carbon emissions depending on the mix of fuel sources the power utilities use. Globally, a kilowatt-hour of electricity produces an average of 475 grams of carbon dioxide, but the figure varies widely from region to region. For example, the average is lower in the European Union (231 grams) than in the United States (about 386 grams). So, the same electric car would create 40% less carbon emissions in the European Union than in the United States.
Almost every electric vehicle on the market will produce lower carbon emissions than gas-powered cars, no matter where they are charged — with the exception of the electric Hummer. Shipped on the global medium-power grid, the 4.5-ton Hummer EV is worse for the climate than many smaller, more efficient gas-burning cars.
But even energy-intensive electric vehicles can help cut carbon emissions in the transportation sector, because there are significant climate benefits to electrifying less efficient cars and trucks. For example, a Hummer EV generates 62% less carbon emissions than a gas-powered Hummer H1. Drivers who switch from a gas-guzzling pickup truck to an electric truck will cut their carbon emissions more than drivers who already drive a gas-efficient sedan and switch to an electric sedan.
“If you ever spoke to a guy who owns a big truck and said, ‘Do you know what to do? You should get the Nissan Leaf, said Sarah Baldwin, director of electrical policy at the Energy Innovation think-tank. “I’ve been doing this business for 17 years and I’ve come to the realization that you can’t change people’s opinions on everything. So let’s just get them cars that look alike. [to what they’re already driving] And make it as clean and sustainably built as possible.”