The 7 lessons learned from 24 million EV miles

The 7 lessons learned from 24 million EV miles

In the world of electric vehicles, nothing attracts as much speculation or disagreement as the debate over exactly how EV drivers behave. Do they need 100 miles of range or will 30 miles do? How many public recharge stations do they need? Do energy prices influence charging? And so on.

The answers to these questions could have huge implications for the success of EVs. If drivers are satisfied with lower-range cars, fewer recharge points and overnight recharging, then the overall challenge of electrifying the nation’s fleet could be resolved at lower costs and more quickly -- with greater economic and environmental benefits.

The best way to answer these questions, of course, is to watch EV drivers and to learn what they’re actually doing.  To assist in that process, the Department of Energy commissioned an industry collaboration -- involving a wide range of carmakers, utilities, retailers, government entities and technology providers -- to help identify current and potential barriers to EV adoption.

Dubbed the EV Project, the program began in late 2010; gathering data from EV drivers willing to share that information. And last week, the EV Project announced it had amassed an unprecedented volume of behavioral data drawn from more than 24 million miles of EV driving.

The DOE awarded management of the project to ECOtality, which manufactures EV charging units and related software. Chevrolet Volt and the Nissan LEAF are project partners, too. Qualifying Volt and LEAF drivers also receive a residential charger and installation at little or no cost to themselves.

“We’re beginning to really see how people are using chargers,” said Colin Read, vice president of corporate development for ECOtality. I spoke with Read while he was in New York City.

So far, the EV Project is tracking some 4,600 vehicles. And including public sites the EV Project is also monitoring 6,200 charging stations, made up mostly of the Type II chargers that operate at 240 volts.

Geographically, the project is tracking EV behavior in 18 markets, including the “Birkenstock Belt”— those eco-conscious parts of West Coast: Washington, Oregon and California -- plus sites in Arizona, Texas, as well as Tennessee, where Nissan builds the LEAF. “We picked regions with very little in common on purpose. We’re seeking a diversity of driver experience,” Read said.

The EV Project is also buying EVs from dealer lots, much like regular consumers do, to understand the overall buying experience. “We call it the ‘Noah’s Ark of EV programs,’ because we buy a pair of every EV on the market,” Read joked. The project does make some exceptions, however, with the most costly models, where just one car is enough.

Image of concept alternative electric vehicle by AlexRoz via Shutterstock.

So, what are some of the project’s early lessons?

  1. The current EV driving distance is modest. According to a pool of EV drivers, made up most of LEAF drivers, average daily mileage is running at 27.7 miles. That distance is very much in line with the overall, rule-of-thumb estimates that most Americans drive less than 40 miles per day.
  1. There’s range anxiety, but not the sort most expected. Project data is showing a curious quirk. There’s been a collective worry that ‘range anxiety’ stifles demand for EV. But data from a small but growing pool of Volt drivers reveals that its drivers work hard to stay in all-battery mode -- rather than routinely taking advantage of the extended range provided by the Volt’s gas engine. To stay within the Volt’s 40-mile battery range and not use any gasoline, “[Volt drivers] are being very disciplined,” Read said. “They want to drive all-electric, so we’re seeing them plug in more frequently than LEAF drivers.”
  1. Recharge times are fairly short. Given these relatively low daily-driving distances, the amount of time EVs are actively drawing power to recharge is averaging about 1.5 hours. The average amount of time the car is plugged in (although not necessarily drawing power) is 8.5 hours. And the bulk of cars are reportedly plugged in during a window that spans 8pm to 8am. The upshot? “Drivers don’t need to recharge continuously overnight,” Read said. This data suggests the transmission grid may be better prepared to handle large volumes of EVs than originally thought.
  1. Price signals work. The EV Project looked at San Diego, where utility San Diego Gas & Electric runs one of the nation’s most sophisticated time-of-day consumer pricing programs. And according to the Project, there’s a strong demand there for low-cost, late-night power. SDG&E sells power at four tiers: full price, half price, one-quarter price and, from midnight till early morning, one-sixth of the full price. “We see almost no charging until midnight, when prices fall to their lowest,” Read said. This has implications for grid use: “The knock that the grid will need more capacity to handle a lot of EVs isn’t true; if we can shift charging to night, it will actually balance out the grid.”
  1. Topping off is habitual, but maybe not necessary. The EV Project data shows that daytime charging rises from 9am to 4pm. “People plug in when they’re at work, regardless of whether they need the charge,” Read said. At the moment, because the daytime chargers are free, this behavior may not be reflecting real-world conditions. “People recharge more out of convenience than out of fear,” Read notes. “If the charger is available and free, they’ll plug in.” But higher prices for daytime pricing are inevitable, he adds, and that change will likely drive down demand for daytime plug time.
  1. Installation costs must fall. ECOtality is also tracking installation costs and procedures in its test markets. The costs to permit and install a home charger vary widely and must come down, Read said. Installation costs can run as high as $1,400, and “this has made us rethink the design of the installation process and charging device,” he said. Earlier chargers had to be hard-wired into the wall -- but now they can be plugged into a heavy-duty 240V wall plug, like those used for clothes dryers or ovens.  
  1. It’s too early to judge true demand. Read’s final point: criticism of EVs in some industry and political circles is premature and unjustified. Critics have been pointing out that the LEAF and Volt fell short of sales targets in 2011, with a total volume of just over 17,000 vehicles. But Read points out that Toyota’s Prius sold just 5,000 units in 2000 – the year when first-generation hybrid cars such as the Prius and the Honda Insight were first sold. “We’re about to see a more real-world test of demand,” he said, with the arrival of Toyota’s plug-in Prius hybrid and the debut of Ford’s battery-powered Focus EV.   

Keep an eye on the EV Project’s progress at