By Sebastian Blanco
Electric-vehicle drivers put about half as many miles on their cars as the average driver. At least, that’s what a new study, conducted by researchers working for the National Bureau of Economic Research (NBER), is estimating. Those results are based on calculations that look at the increase in home energy usage for homes with EVs in California.
The study authors did not ask the EV drivers themselves. Nor did they check odometer readings through service records or using other methods. They do admit that getting that kind of information would be best but that these numbers are “within the vehicles themselves” and that automakers keep charging information private “due to strategic business interests and privacy concerns.”
So, as a workaround, researchers from the University of Chicago, University of California Davis, and UC Berkeley instead drew their estimates from a sample of roughly 10 percent of the residential electricity meters from Pacific Gas & Electric (a total of 362,945 households). These meter readings were then compared with EV registration records from 2014 through 2017 and the addresses where an EV was registered—a total of 57,290 electric vehicles—were then checked to see how much extra energy was used there to arrive at an estimate about how much extra household electricity was required once an EV was purchased. The result was 0.12 kilowatt-hours (kWh) per hour, or 2.9 kilowatt-hours each day. Another factor taken into consideration came from the California Air Resources Board, which has estimated that “upward of 85 percent of EV charging occurs at home.”