The pure electric Nissan Leaf costs just 3.5 cents a mile based on the national average of 11 cents/kWh of electricity. That’s less than half of what it costs to drive the most fuel-efficient four-door car we’ve tested, the Toyota Prius. (This calculation doesn’t include other costs such as maintenance or depreciation. But maintenance on an electric car is theoretically miniscule compared with gasoline cars. And depreciation is unknown for such a new technology.)
The Chevrolet Volt, which runs on electricity for the first 35 miles, is heavier and therefore costs a little more to run—about 3.8 cents per mile on electricity. After that, the Volt uses a gasoline engine to extend the range another 300 miles. In gas mode, the Volt ties the Toyota Corolla in overall fuel economy at 32 mpg, although the Volt uses premium fuel. That gives the Volt a fuel cost on gasoline of 12.5 cents a mile once the batteries have been exhausted.
The chart below compares the costs of driving these plug-in vehicles with the most fuel-efficient current gasoline-powered cars in our tests and shows how costs break down. With an all-electric car like the Leaf, short trips cost about half as much as other cars. The farther you go, the more you save--up to the Leaf’s maximum range of about 75 miles on average. Trips longer than that are impractical in the Leaf, because it takes about 6 hours to recharge before going the next 75 miles.
Even on longer trips, the Volt running on gasoline is still cheaper to drive than the Toyota Prius hybrid, the most fuel-efficient vehicle in our database, because of the money you save driving the first miles on electricity. The Prius has the advantage on trips over 100 miles.
In miles-per-gallon terms, we found the Leaf gets the energy equivalent of 106 mpg, based on efficiency of 3.16 miles per kilowatt-hour of electricity. If you charge it at national average electric rates of 11 cents per kilowatt hour, you’ll pay about $2.42 to charge the car. (Admittedly, electric rates at our test track in rural Connecticut are almost double that: 19 cents per kWh. Along with New York, Connecticut has the highest rates of any state in the continental United States. But even at that rate, the Leaf costs about 20-percent less than the Prius to operate and about half the cost of the Corolla.)
As today’s technologies improve, prices decrease, and new plug-in cars are developed, EVs and hybrids will offer an increasingly attractive option for car buyers. And already, in terms of pure energy costs, the balance is in their favor.