December represents our twelfth month with the 2011 Chevrolet Volt, and that makes this update a one year summary of our Volt's thirst and, well, whatever Bender calls it when he needs a jolt.
In the past 12 months our Volt has amassed just over 13,000 miles. That number could have been higher if we had encouraged more long road trips, but the number of long trips 20 people take in a year is far more than a single owner would take, and that would have skewed the results too far in the gasoline direction, which is most definitely not the Volt's sweet spot.
As it was our Volt was already being driven by staffers who live too far away to make best use of the EV part of its split personality (raises hand). Combine that with the handful of long trips it did make and you get our observed Utility Factor of just 43 percent. The Society of Automotive engineers reckons a plug-in hybrid with 35 miles of rated range should run on electricity 58 percent of the time in the hands of a typical consumer. We reckon they're right.
2011 Chevrolet Volt Best Worst Average EPA Electricity (kWh/100 mi) 22.9 58.4 34.2 36 Electric Range (miles) 54.6 23.5 37.3 35 Gasoline (mpg) 42.6 21.8 34.3 37
Our average electric range (from fully charged to fully discharged) was 37.3 miles, and that was derived from 96 data points. Twice that many partial discharges can't be counted because the car was plugged in again before it ran out of juice -- which we encouraged because that's what you'd do if you were trying to run on electrons as much as possible.
In perfect semi-traffic conditions I managed to smash through the 50-mile barrier twice -- 54.6 and 54.3 miles on consecutive charges -- though no one else did. In my case, perfect conditions meant nearly-clogged freeway traffic that rolled steadily at 35-50 mph without any stopping or sudden speed changes.
We also beat the EPA's estimate for average electricity consumption. Our average was 34.2 kilowatt-hours used every 100 miles instead of the rated 36 kWh/100 miles.
On the other hand, gasoline fuel consumption was worse than the EPA combined rating, 34.3 mpg actual versus 37 mpg rated. Before you say we didn't drive enough long-distance highway miles, please remember that hybrids do better in the city, where speeds are lower, regenerative braking is in effect and electric motors are more efficient. Note that our longest e-range occured at sub-freeway speeds. At regular freeway speeds the Volt's engine is doing two things at once, generating electricity on the one hand while assiting with direct mechanical propulsion with the other, which means it's working that much harder.
What all this points to is an EPA gasoline consumption rating method that is equally optimistic when this plug-in is burning gasoline as it is when certain brands of traditional gasoline-powered cars are on the dyno rollers. Maybe the EPA and NHTSA should take another look at their methodology. It's hard to see how we would beat electricity by 5 percent and miss gasoline by 8 percent, but we did.
On the other hand, human nature could explain it. Think of the conversation in your head going like this: "I'm out of juice and am now burning gasoline. I have no more range to maximize. The videogame is over. I need no longer drive like Ed Begly Jr. Time to make up for lost time."
Comparing notes with others in the office, the Ed Begley Jr. effect seems to be a real thing.
|
2011 Chevrolet Volt |
Sept |
Oct/Nov |
Dec |
Overall |
|
Utility Factor (% EV miles) |
49% |
53% |
51% |
43% |
|
Apparent MPG (ignore electricity) |
71.9 |
70.8 |
73.3 |
59.8 |
|
Cost per mile (US average prices) |
7.1¢ |
7.4¢ |
7.2¢ |
8.1¢ |
|
(Cal. average prices) |
8.1¢ |
8.4¢ |
8.0¢ |
8.9¢ |
|
Popular hybrids, for reference |
Sept |
Oct/Nov |
Dec |
Overall |
|
2011 Toyota Prius (US average prices) |
6.8¢ |
6.6¢ |
6.7¢ |
7.1¢ |
|
(Cal. avg prices) |
7.6¢ |
7.3¢ |
7.4¢ |
7.6¢ |
|
2011 Ford Fusion Hybrid (US avg prices) |
8.7¢ |
8.4¢ |
8.7¢ |
9.1¢ |
|
(Cal. avg prices) |
9.8¢ |
9.3¢ |
9.5¢ |
9.8¢ |
I found a flaw in my October/November data, in which I left some electricity consumption out of the cost calculations. The gray boxed have been revised upwards, which, frankly, makes them make more sense.
In the end, the cost to operate our 2011 Chevrolet Volt in National Average terms worked out to 8.1 cents per mile. As it happens, a Toyota Prius would have cost a penny less per mile and a Ford Fusion a penny more, assuming both spent the year running at EPA combined. Any hybrid owner will tell you this is unlikely, indeed.
And that's at a yearlong Utility Factor of 43 percent. One column to the left, where December's average UF was 51 percent, the cost per mile was 7.2 cents. And if you can achieve the SAE's predicted 58 percent UF, the cost per mile drops into the 6-point-something cent range. And it'd be far less than that if you lived in Washington State, where they practically pay you to take electricity off their hands.
Bottom line: the cost to operate the Volt (and whether it makes economic sense to you or not) is entirely dependent on how far you drive every day between plug-ins, how much of that is wide-open freeway and what you pay for electricity.
Furthermore, the Volt's medium sized battery takes about 12 kWh to fill from empty on any given day, which is totally doable overnight (or during a standard 8-hours-plus-lunch workday)on standard 120V electricity from a regular outlet. Pure electric cars with larger batteries can't say that; they need the 240V charger.
Of course, you first have to swallow the price of the thing. Factor that in and the stronger gasoline hybrids may come out cheaper in the long run.
Yeah, there's math involved.
Dan Edmunds, Director of Vehicle Testing
isend2c says:
08:34 PM, 01/10/12
this is a great write-up Dan, you looked at so many variables which is exactly what should be check out. As well as asking others their opinions about the electric vs gas efficiency.
mrrizzo says:
04:20 AM, 01/11/12
I've had my Volt since March and will hit 10K miles soon. So far I've used about 60 gallons of gas. My electric range mirrors yours somewhat from a worst of 28 miles to a max of 52 miles. My daily commute is about 20 miles round trip. Where I differ is gas mileage while in charge sustaining mode. This past summer I took a 900 mile (round) trip to the Outer Banks of NC and averaged 41 mpg. This was in 100 degree heat with the AC running. The same trip the previous year in a VW CC averaged 29 mpg. Another trip to Cape Cod used gas at a rate of 44 mpg. Of those 60 gallons, roughly 22 of them were used in that one trip to NC. Looks like your staff lead-footed it after the battery changed over which is a mistake as you can earn back electric miles while in CS mode by driving in LOW (more regenerative charge back while coasting). There will be periods that you are running totally electric even when in CS mode if you drive effectively.
marclee says:
05:27 AM, 01/11/12
GM has stated that the average utility factor is around 70%, which mirrors nicely the data for 360 Volts being tracked at http://www.voltstats.net/
Your 43% would rank you 336 out of 360 there, and many cars there have clearly been taken on huge cross country trips or just frequent long trips. Which is not to say you can't do lots of miles and stay electric. In a 11 months of driving I have covered 17500 miles and have "utility" factor over 93%.
I also concur with "mrrizzo" when burning gas for an extended period of time I typically see mpg in the 41-45 mpg range.
I know your response to all this would be, we just drive it like we would a "normal" car. Clearly most people who have bought this car are doing much better with it. I attribute this to the fact that you do not actually own the vehicle. For example, the classic post where one of your writers stated that "as I was driving the Volt home I began to think about where was I going to plug it in." Needless to say no suitable outlet could be found.
Anyone who would buy the vehicle would make sure they had either a 240v charging station or at the least a suitable 120v outlet before spending $40k on car.
sniperruff says:
05:42 AM, 01/11/12
@marclee:
"I know your response to all this would be, we just drive it like we would a "normal" car. Clearly most people who have bought this car are doing much better with it. I attribute this to the fact that you do not actually own the vehicle."
- Or rather, purchasers of the Volt are generally more interested in seeing how it'll perform in terms of MPG and therefore may drive more conservatively.
"Anyone who would buy the vehicle would make sure they had either a 240v charging station or at the least a suitable 120v outlet before spending $40k on car."
- That's assuming someone with a stable job with close to zero travel, does not go anywhere outside of commuting to/from work. The Volt becomes more expensive the more you stray outside of your commute, or lend your car to someone else (say, your children).
Personally, I regard the Volt as a Nissan Leaf with a $10k range-extending option in the form of a gasoline engine. More R&D should be spent on making more efficient conventional cars instead.
nelsonlu says:
05:56 AM, 01/11/12
sniperruff says, in response to marclee:
"Anyone who would buy the vehicle would make sure they had either a 240v charging station or at the least a suitable 120v outlet before spending $40k on car."
- That's assuming someone with a stable job with close to zero travel, does not go anywhere outside of commuting to/from work. The Volt becomes more expensive the more you stray outside of your commute, or lend your car to someone else (say, your children).
Every car becomes more expensive the more you stray outside your commute, or lend your car to someone else (say, your children). What's your point?
sniperruff says:
06:55 AM, 01/11/12
@nelsonlu:
"Every car becomes more expensive the more you stray outside your commute, or lend your car to someone else (say, your children). What's your point?"
- In a Prius :
You drive to work @ 7.1¢/mile
Your wife borrows your car and drive to the mall @ 7.1¢/mile
Your children borrows your car to visit grandma @ 7.1¢/mile
Compare to the Volt:
You drive to work with cheap electricity (assuming electricity is cheap or generated from solar panels).
Your wife borrows your car and drive to the mall @ 8.1¢/mile, after battery is exhausted
Your children borrows your car to visit grandma @ 8.1¢/mile, after battery is exhausted
That is my point. As soon as you stop driving the Volt like an EV is intended to (daily commute with set mile), it becomes a $40k Toyota Prius with more bling and less mpg.
ed124c says:
07:37 AM, 01/11/12
I used to think that hybrids were a transitional product, waiting patiently for the holy grail of pure electric with a 500 mile range and a five minute recharge.
Now, with the astounding reliability of the Prius, and the slow development of long range batteries, I think hybrids will be here for at least a few more decades, and probably longer if we get any more Great Recessions.
I looked at a Prius V, and thought that this was something I could buy-- reasonably priced (27K), great mileage (not as good as a Prius, but good enough), and as roomy as any compact crossover. Now all Toyota needs is an AWD version. (Electronically controlled electric motors at each rear wheel?)
actualsize says:
08:25 AM, 01/11/12
So what you guys are saying is that you actual Volt owners drive like Ed Begley, Jr. all the time. And the demographic of early adopters who have bought the Volt with their own money more closely matches Ed Begley, Jr. than the average driver out there, let alone enthusiasts. ;)
I can see that. And I agree that while many of the drivers in our office are curious about it, and want to understand it, and get into the electric side of things, at the end of the day they aren't Volt material. They're not hyper-vigilant when it comes to plugging in ALL the time and their curiosity evaporates as soon as it switches from battery to gasoline power. Also, my record-keeping logbook, without which we would have NONE of this data, was considered a pain in the butt by many.
bodyblue says:
08:35 AM, 01/11/12
"as it is when certain brands of traditional gasoline-powered cars are on the dyno rollers"
Dan, why be coy? Just tell us which brands you are talking about.
bodyblue says:
09:25 AM, 01/11/12
Oh and I will be the first to say that I am impressed with how reliable the Volt has been. Kudos to GM for producing such a car in a crazy time it its corporate life.
csubowtie says:
11:53 AM, 01/11/12
"- In a Prius :
You drive to work @ 7.1¢/mile
Your wife borrows your car and drive to the mall @ 7.1¢/mile
Your children"... would rather walk.
mfennell says:
05:12 AM, 01/12/12
Dan,
I read the SAE definition of Utility Factor differently. the chart you refer to says that at 35 miles EV, 58% of drivers will be purely EV in a given day, which is completely different from your interpretation.
Consider the math: if 35 miles means 58% EV miles, the average driver must drive (35/0.58)= 60 miles, which is 22k miles a year. Obviously not true.
On Ed Begly driving: the over/under for 40mpg seems to be right around 73mph over a long driving (excluding EV miles from the calculation of course). My 75-80+mph 150 mile drive returned 36 yesterday, which I can't complain about. My 2000 XJR returns 18 in similar (possibly more aggressive :) ) driving.
Ironically, people with very high EV percentages can show crappy mileage. They tend to have very short engine runs, which is an mpg killer.
mfennell says:
05:20 AM, 01/12/12
Final comment: the obsession on cost per mile is misplaced. The EV experience is worth a premium. Silent operation, instant response, no warm up, no (fewer in this case) gas stations. As I've said before, I didn't get it to save anything. Money, the world, GM, etc. I got it because I think it's a great car and I enjoy driving it.
sniperruff says:
05:44 AM, 01/12/12
@mfennell :
"I got it because I think it's a great car and I enjoy driving it. "
That pretty much sums it up. I personally like the Prius because it combines existing technology (low drag profile, low rolling resistance tires, regenerative braking, etc.) into a single, affordable package that's cheap to run. I don't get all the hate towards the car.
I personally would get a simple, small hatchback for a commuter.
bodyblue says:
08:20 AM, 01/12/12
"I don't get all the hate towards the car. "
I dont either. I think a lot of it is just fear that if hybrids become more popular then the high performance cars will be less available. Then again some people just hate things they dont like or understand. The best thing about the Prius IMO is the stupid good reliability. My wifes 2004 has had one water pump failure (covered by Toyota at 89K) and some tires and oil changes in 95K miles, period. How could someone not be impressed by that? Especially since in 2004 it was a brand new design......oh and the 43 MPG average over its lifetime is nice as well.
throwback says:
08:48 AM, 01/12/12
"I don't get all the hate towards the car.'
This is an enthusiats blog, enthusiats like cars that are exciting drive. The Prius has many virtues, driving excitement is not one of them. I don't hate any car, but like most enthusiasts I prefer a car that rewards driver involvement, not discourages it.
rcb268 says:
11:34 AM, 01/12/12
In response to mfennell, all I can add is "Amen!"
bodyblue says:
04:47 PM, 01/12/12
"enthusiats like cars that are exciting drive. "
That is rather silly if you think about it. Being "enthusiastic" about something is just that; enthusiasm. One cant be enthusiastic about different aspects of cars? Where is the law that says that one must ONLY be enthusiastic about exciting cars? I find most cars interesting really.....fast or slow...big and small. A Prius is still a tech marvel even 8 years on. Why put 'enthusiasts" in a box and make them only like one type of car?