The percentage of income spent on transportation energy, such as the gasoline or electricity that powers automobiles, SUVs, and pickup trucks, would decrease for more than 90% of vehicle-owning households in the United States if they switched to electric cars.
A recent University of Michigan study found that households that switch from gas-powered to electric vehicles also cut the amount of greenhouse gases they produce by more than 90%.
However, more than half of the lowest-income U.S. households (an estimated 8.3 million households) would continue to experience high transportation energy burdens, defined in this study as spending more than 4% of household income on filling the tank or charging up.
“Our results confirm the potential for widespread benefits from EV adoption,” said study corresponding author Joshua Newell, an urban geographer at the U-M Center for Sustainable Systems, part of the School for Environment and Sustainability.
“However, EV ownership in the U.S. has thus far been dominated by households with higher incomes and education levels, leaving the most vulnerable populations behind. Policy interventions are needed to increase EV accessibility so that all Americans can benefit from the EV transition.”
The new study is scheduled for publication January 11, 2023, in Environmental Research Letters, an IOP Publishing journal. It is the first analysis to take into account how EV energy costs and greenhouse gas emissions vary geographically across the nation.
It is also the first study to calculate the EV energy burden (the percentage of income spent on EV charging) for the entire United States and investigate EV energy expenses through the perspective of distributive justice. Distributive justice concerns the fair distribution of benefits and burdens.
Our analysis indicates that future grid decarbonization, current and future fuel prices, and charging accessibility will impact the extent to which EV benefits will be realized, including lowering transportation energy burdens for low-income households.
Greg Keoleian
EVs currently account for about 1% of the cars, SUVs and pickups on American roads. According to the current study, if all of those vehicles were switched out for brand-new EVs, the transportation energy costs and related greenhouse gas emissions would differ greatly from place to place.
The West Coast and parts of the Northeast would experience the greatest reductions in transportation energy use and GHG emissions, mostly because of cleaner energy systems and more affordable electricity.
Households in some locations could reduce their annual transportation-energy costs by $600 or more, and cut their annual carbon footprint by more than 4.1 metric tons of carbon dioxide equivalents, by buying a new EV.
“But lower-income households in other parts of the country wouldn’t fare as well,” Newell said.
Very high EV transportation energy burdens, ranging from 10% to 64%, would persist for the lowest-income households and would be concentrated in the Midwest and in the two states with the highest electricity prices: Hawaii and Alaska.
By choosing an EV, 8.3% of American households (about 9.6 million homes) would experience only modest reductions in their transportation energy use and greenhouse gas emissions. The majority of “both low” households are found in Midwest states like Michigan, but they are dispersed all throughout the country.
These modest EV savings can be attributed to a variety of factors, such as the battery-damaging effects of cold winter weather, heavily fossil fuel-dependent electrical networks, or higher electricity pricing than gasoline prices.
According to the study, the lowest-income households would continue to experience the highest transportation energy burdens. Essentially all households with incomes of less than 30% of the local median would experience moderate or high EV energy burdens.
“We identified disparities that will require targeted policies to promote energy justice in lower-income communities including the subsidizing of charging infrastructure as well as strategies to reduce electricity costs and increase the availability of low-carbon transportation modes such as public transit, bicycling and car sharing,” said study lead author Jesse Vega-Perkins, who did the work for a master’s thesis at the U-M School for Environment and Sustainability.
“Our analysis indicates that future grid decarbonization, current and future fuel prices, and charging accessibility will impact the extent to which EV benefits will be realized, including lowering transportation energy burdens for low-income households,” said study senior author Greg Keoleian, director of U-M’s Center for Sustainable Systems.
Three aspects of the EV transition were examined in the study using a geographic model: the transportation energy load, fuel prices (i.e., the price of gas or electricity required to charge an EV), and greenhouse gas emissions.
The analysis does not include vehicle purchase cost. Total cost of ownership of EVs is the focus of a current study by the Center for Sustainable Systems.
At the census tract level, the researchers calculated the lifetime greenhouse gas emissions of new battery-electric and internal-combustion automobiles. The energy demands of the new cars were then contrasted with those of the stock of current on-road vehicles.
Finally, they evaluated the geographic distribution and intensity of energy costs and greenhouse gas emissions across the United States for EVs and internal combustion vehicles.
Transportation accounts for the largest portion of the greenhouse gases emitted in the United States, with direct emissions from passenger vehicles and light-duty trucks comprising roughly 16% of U.S. emissions. Electrification is seen as the primary pathway to reducing those emissions.
The University of Michigan School for Environment and Sustainability provided funds for the project.
