- Without access to everyone's odometer, researchers working for the National Bureau of Economic Research have used a limited set of utility and electric-vehicle registration data to see how much extra electricity EV owners use each day.
- The number, 2.9 kWh, was then run through a formula with a number of other factors to come to an estimate that EV drivers go around 5300 miles a year. That's about half of what gas-powered cars do each year.
- This is all from a non-peer-reviewed study, so there may be adjustments down the road, but a separate survey conducted by Plug In America found that EV drivers are more than happy with their cars, and 96 percent plan to buy an EV when the time comes for new wheels.
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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."
The official miles-per-kWh energy use of the vehicles in the survey was also included, and all of these numbers were then used to estimate that "EVs travel 5300 miles per year, under half of the U.S. fleet average," the study said.
As for what this all might mean for electric utilities and regulators, the paper doesn't get into, other than to say that the 5300-mile annual estimate is "roughly half" the amount assumed by regulators in California. The reason for this could be smaller sample sizes used by those regulators and "selection bias in the official estimates."
For the auto industry as a whole, it's interesting to contemplate the study's conclusion that EVs just don't travel as many miles as gas-powered cars. The authors say this "raises important questions about the potential for the technology to replace a vast majority of trips currently using gasoline." The authors say their results suggest that "EVs may not be as easily substituted for gasoline vehicles as previously thought."
However many zero-emission miles EV drivers are actually putting on their vehicles, it appears they're pleased with the results. A new survey put out by Plug In America (PIA) found that 96 percent of EV owners are likely to purchase an EV as their next vehicle and that the ability to charge their car cheaply at home was the second-highest consideration for EV buyers (the federal tax credit was number one, but only just). PIA's study of EV owners also found that, while over 90 percent of them charge at home every day or at least every week, "the majority also charge in public."
It should be noted that the NBER study has not been peer reviewed and is being circulated "for discussion and comment purposes" at this point.