LOS ANGELES — Do electric vehicles really help the environment, or do they just push the emissions problem to the power grid? That’s the skeptics’ view of battery electrics that plug in rather than refuel at the gas pump.
But a new analysis from the Union of Concerned Scientists released Monday found the average gas car would need to get 93 miles per gallon to generate fewer greenhouse gas emissions than an average battery electric vehicle.
“There’s an ongoing question of electricity not being perfectly clean, so what is the net benefit of switching to an EV?” said David Reichmuth, a senior engineer with the nonprofit science advocacy group who conducted the research.
Electric vehicles generate zero emissions when they are driven, but they have to get their power somewhere, and not all power utilities are equal. While some generate electricity with renewable energy sources such as wind, solar, nuclear and geothermal, many others use fossil fuels such as coal, natural gas and petroleum.
Factoring in the source of electricity, an EV’s true emissions will vary based on where it’s plugged in.
An EV driven in upstate New York, where 25% of the electricity comes from fossil fuels, generated the fewest greenhouse gas emissions, according to Reichmuth’s research. A gas-powered car would need to get 255 miles per gallon to match an average battery electric’s emissions.
In California, where 45% of electricity is currently generated from fossil fuels, a gas car would need to get 134 mpg to match an EV.
In Hawaii, which relies largely on petroleum for its utility grid, a gas-powered car that gets 36 mpg generates roughly the same emissions as an EV.
“It’s really due to the difference in electricity generation,” said Reichmuth, who combined electricity power plant emissions data from the U.S. Environmental Protection Agency with the latest fuel emissions and vehicle efficiency data to determine well-to-wheel emissions in every state for cars and light-duty trucks powered with electricity and gas.
To assess their total emissions, Reichmuth looked at emissions generated not only from driving both types of vehicles but from fueling them. For a gas car, that meant looking at emissions generated from extracting crude oil from the ground, transporting it to a refinery, making it into gas and then transporting that gas to filling stations.
For an electric car, that meant calculating power plant emissions as well as emissions generated from the production of coal, natural gas and other fuels power plants use to generate electricity.
While the EVs that generated the fewest emissions were in parts of the country where the electricity grid is least dependent on fossil fuels, Reichmuth found that driving an EV anywhere in the U.S. produces fewer emissions than driving a gas-powered car or truck with average fuel economy.
According to the U.S. Department of Energy website, the average new gas-powered car gets 31 mpg, while the average new light-duty truck gets 23 mpg. Even the most fuel-efficient gas car on the market — the 59-mpg Hyundai Ioniq Blue — generates more emissions than the average EV in nearly every state.
As electric utilities generate more of their power from renewables, as President Biden is proposing in his infrastructure plan, the wider the greenhouse-gas-emitting gap becomes in EVs' favor. Since 2018, when the Union of Concerned Scientists made its first well-to-wheel comparison, battery electrics are generating 15% fewer emissions.
“The goal is to make sure we have clean electricity and pair it to run our transportation,” Reichmuth said.
Transportation accounts for 29% of greenhouse gas emissions in the country, according to the U..S. Environmental Protection Agency, with passenger vehicles contributing the largest share.
“The question is what are the total emissions,” Reichmuth said. “That’s what we need to reduce. There are benefits from reducing tailpipe emissions for air quality reasons, but it’s important to know the total emissions because that’s what leads to the negative impacts of climate change. That’s why we need to look at the true benefits of EVs rather than just focusing on tailpipes.”