With the Chevrolet Volt collecting awards at a dizzying pace, this extended-range electric car or hybrid plus warrants a closer look to see if it truly lives up to the hype. We have spent significant time behind the wheel, including last month in a Volt borrowed from General Motors. This loan provided first-hand experience living with it—driving, charging, and fueling. We’ll be buying our own as soon as they go on sale here in Connecticut. Meanwhile, here are our initial findings.
The most commonly asked questions we get about the Volt are what is it like compared with a hybrid; how far can it go before needing a recharge; and what sort of energy use or fuel economy do you actually get. I’ll address the range question first.
Since the Volt runs on battery power for the first 30 to 40 miles, any mpg figure is meaningless without knowing the length of your trip and whether you recharge the battery along the way. Any cost associated with running a Volt will depend on the price of electric power in your area. The EPA has recently announced the mpg estimates it has calculated and that will be affixed to Volt’s window stickers. We lay out our experience below.
To get a sense of the Volt’s energy consumption in typical real-world use, we had several staffers pilot the car on their daily commutes and then we logged both the fuel they used, if any, and the electricity it took to recharge the batteries, using one of the commercial-grade chargers we have at our Auto Test Center.
On the whole, we found that in electric mode the Volt uses energy more sparingly than any other hybrid or diesel car. We also found that its fuel consumption when it’s operating on the gasoline-fueled engine is not that great. Bear in mind that these findings are anecdotal and are not the official ones that we’ll publish after testing our own Volt thoroughly.
Our Volt experience:
The Volt uses its battery power upfront, running all-electric until the battery is substantially depleted, and then using the gasoline engine to generate power to run it further. GM initially claimed a 40-mile all-electric range but recently moderated that to “between 25 and 50 miles.” We typically got between 29 and 34 miles when running on electricity alone.
We kept the car’s climate control in Auto mode during our trials, and the outdoor temperatures averaged about 50 degrees F during our stint with the Volt. As in all EV cars, running the heater cuts down the electric range significantly. We used our Coulomb Technologies charging stations, which at 220-volt level took about four hours and 20 minutes per session and consumed about 12.5 kWh of electricity each time.
Here’s an example of how mpg is a function of the trip mileage: During one 72-mile mostly highway commute, the car ate up its electric range in 29 miles and posted an overall fuel consumption of 60 mpg. The energy consumed came from a full electric charge and 1.1 gallons of gasoline. Piling on 130 more miles without charging resulted in 48 mpg. (For comparison, our Toyota Prius gets 47 mpg on that particular 200-mile route. Read our impressions of the upcoming Toyota Prius Plug-In Hybrid.)
Over numerous trips, our collective average for electric-only range was 33 miles. Once the battery is depleted and the car is essentially using only gasoline as its fuel, we averaged 30 mpg overall in mixed driving. While 30 mpg is good in general, it is no better than a conventional small sedan or subcompact.
Cost parity:
Clearly, reaping the benefits of electric-car use means keeping the Volt’s battery charged up as much as possible. When we did that, and the Volt only used its gas engine occasionally, the car’s on-board computer indicated we were getting six-figure mpg display of 120 mpg or so. But such a fantastic number is misleading since it ignores the cost of the 12 kWh of electricity we were “pumping” into the car every 33 miles or so. Here in the Northeast, or in California, that ends up being about $2.38 (With the national average of 11cents per kWh, it would be $1.38.)
That raises the question of which other cars give you 33 miles for $2.38. With today’s national average for regular at $2.96, that equates to 41 mpg. That’s comparable to, say, a Honda Civic Hybrid (37 mpg) or Honda Insight (38 mpg). Calculating price parity with the diesel world, using diesel prices at $3.20/gallon, it works out to be 44 mpg. That brings to mind the manual-transmission Volkswagen Golf TDI or Jetta TDI, which deliver 38 and 36 mpg overall, respectively. So in these conditions, the Volt comes out ahead of virtually all fuel sippers except for the Toyota Prius on cost per mile. The Prius yields 44 mpg overall consistently. The Volt, which will set you back something like $33,500 even after federal tax credits, is considerably more expensive to buy than any of these cars. And, it’s only a four-seater.
Cost parity for initial 33 miles EV range | ||
In NY/CT at 19c/kwh | National average 11c/kwh | |
Cost | $2.38 | $1.38 |
mpg for equivalent cost | 41 mpg | 71 mpg |
Volt energy consumption: Since the cost of gasoline and electricity are variables that tend to be in constant flux, and often apply a specific geographical factor to the Volt’s merits, it would be appropriate to look at the Volt in a purely scientific way. In electric mode, we averaged 38 kWh/100 miles. For comparison, according to the window sticker, the EPA estimates 36 kWh/100 miles. Given that 33.7 kWh has been established as the energy equivalent of one mpg by the EPA, our average use worked out to 89 mpg-equivalent (MPGe) in electric mode. But before we jump with joy, remember, this applies only to the initial 33 miles of electric-only range.
Miles/kWh | kWh/100 miles | MPGe in EV mode | MPG gasoline only |
2.64 | 38 kWh | 89 MPGe | 30 mpg |
What about the driving experience?
We’ve commented previously on the Volt’s quick, smooth, powerful acceleration in EV mode. The transition to gasoline mode is smooth and the car continues to feel responsive. There is some muted engine hum in the background, and sometimes during coasting the revs are kept up instead of dropping to idle, which garnered comments ranging from “odd” to “annoying.” When I described this to Micky Bly, GM’s executive director for electrical systems, at the LA Auto Show, he said that backing off on the revs during coasting is in the works. Even when the electric power is gone, the Volt saves some of its battery capacity (GM calls it “buffer”) to be able to power the car electrically at low speeds, while in reverse, and for maintaining accessories while it shuts off at idle, as with other hybrids. For that purpose, the battery management system keeps it at about 20-percent charged. The buffer is also used to provide extra oomph while climbing a long hill.
Interim conclusion:
The Volt works, but depending on how it is used and where, it may not save you money, especially in the Northeast or California. In those regions especially, the Prius remains a proven, more cost-effective choice for green motoring.
Of course, money-saving is not the Volt’s only raison-de-d’être. This is an electric-drive car that conserves energy in electric mode and does not come with range anxiety. As such, it advances the cause of reducing greenhouse gases and reducing our reliance on foreign oil. According to our recent green-car survey, saving money is not the number one goal for EV intenders, anyway.
It goes without saying that if gasoline prices go up significantly, or if you live in a region where electricity is cheap, then any cost-based energy-use calculation will tip the scales more in the Volt’s favor—but there is no getting around the high purchase price and modest fuel economy if straying beyond the EV range.
We’ll dig into the Volt deeper once we purchase one and run it through our extensive test program.
Copyright © 2006-2010 Consumers Union of U.S., Inc. No reproduction, in whole or in part, without written permission.
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