Chevy Volt gets 230 mpg, but how?
Neither General Motors nor the EPA are making declarative statements about how, exactly, the 2011 Chevy Volt will achieve it's much-touted 230 mpg rating that was announced today. GM's most clear statement (available in full after the break) says that some consumers "may be able to be in pure electric mode on a daily basis without having to use any gas" and that "key to high-mileage performance is for a Volt driver to plug into the electric grid at least once each day." Without access to the actual method that the EPA is tentatively going to apply to plug-in vehicles (we have requests for clarification out to the EPA), all that GM's Dave Darovitz would tell us is that the number is "based on city cycles and we're not really talking in detail yet." Instead, the press release says that:
Frank Weber, vehicle chief engineer for the Volt, told AutoblogGreen that the EPA's method takes into account the two extremes: People who plug in every chance they get and therefore barely ever need gasoline and people who never plug in (if you're buying a Volt and never plug it in, we'd like to offer you a bridge or two. Call us). By figuring out what the average driver will do with the Volt, the EPA has declared that 230 mpg is reasonable. Weber said, "The number is in the ballpark, it is not unrealistic. The moment you are driving shorter trips, or you go on longer trips and look at your average fuel economy, this number is achievable."Under the new methodology being developed, EPA weights plug-in electric vehicles as traveling more city miles than highway miles on only electricity. The EPA methodology uses kilowatt hours per 100 miles traveled to define the electrical efficiency of plug-ins. Applying EPA's methodology, GM expects the Volt to consume as little as 25 kilowatt hours per 100 miles in city driving. At the U.S. average cost of electricity (approximately 11 cents per kWh), a typical Volt driver would pay about $2.75 for electricity to travel 100 miles, or less than 3 cents per mile.
Keep in mind, the 230 mpg number is only valid for the Volt's city cycle. On the highway, the number will be closer to 100 mpg. Still impressive to look at, and the first car to get triple digits from the EPA. As you can read in this detailed PDF from NREL, there is much more to think about in calculating the fuel economy of PHEVs than simply how far it can go on a single charge and then what its "regular" mpg rating is. At least, there's more to it if you're the EPA.
[Source: GM, NREL, Consumer Reports]
PRESS RELEASE:
Chevrolet Volt Expects 230 mpg in City Driving
* First mass-produced vehicle to claim more than 100 mpg composite fuel economy
* Tentative EPA methodology results show 25 kilowatt hours/100 miles electrical efficiency in city cycle
* Plugging in daily is key to high-mileage performance
WARREN, Mich. - The Chevrolet Volt extended-range electric vehicle is expected to achieve city fuel economy of at least 230 miles per gallon, based on development testing using a draft EPA federal fuel economy methodology for labeling for plug-in electric vehicles.
The Volt, which is scheduled to start production in late 2010 as a 2011 model, is expected to travel up to 40 miles on electricity from a single battery charge and be able to extend its overall range to more than 300 miles with its flex fuel-powered engine-generator.
"From the data we've seen, many Chevy Volt drivers may be able to be in pure electric mode on a daily basis without having to use any gas," said GM Chief Executive Officer Fritz Henderson. "EPA labels are a yardstick for customers to compare the fuel efficiency of vehicles. So, a vehicle like the Volt that achieves a composite triple-digit fuel economy is a game-changer."
According to U.S. Department of Transportation data, nearly eight of 10 Americans commute fewer than 40 miles a day http://tinyurl.com/U-S-DOTStudy .
"The key to high-mileage performance is for a Volt driver to plug into the electric grid at least once each day," Henderson said.
Volt drivers' actual gas-free mileage will vary depending on how far they travel and other factors, such as how much cargo or how many passengers they carry and how much the air conditioner or other accessories are used. Based on the results of unofficial development testing of pre-production prototypes, the Volt has achieved 40 miles of electric-only, petroleum-free driving in both EPA city and highway test cycles.
Under the new methodology being developed, EPA weights plug-in electric vehicles as traveling more city miles than highway miles on only electricity. The EPA methodology uses kilowatt hours per 100 miles traveled to define the electrical efficiency of plug-ins. Applying EPA's methodology, GM expects the Volt to consume as little as 25 kilowatt hours per 100 miles in city driving. At the U.S. average cost of electricity (approximately 11 cents per kWh), a typical Volt driver would pay about $2.75 for electricity to travel 100 miles, or less than 3 cents per mile.
The Chevrolet Volt uses grid electricity as its primary source of energy to propel the car. There are two modes of operation: Electric and Extended-Range. In electric mode, the Volt will not use gasoline or produce tailpipe emissions when driving. During this primary mode of operation, the Volt is powered by electrical energy stored in its 16 kWh lithium-ion battery pack.
When the battery reaches a minimum state of charge, the Volt automatically switches to Extended-Range mode. In this secondary mode of operation, an engine-generator produces electricity to power the vehicle. The energy stored in the battery supplements the engine-generator when additional power is needed during heavy accelerations or on steep inclines.
"The 230 city mpg number is a great indication of the capabilities of the Volt's electric propulsion system and its ability to displace gasoline," said Frank Weber, global vehicle line executive for the Volt. "Actual testing with production vehicles will occur next year closer to vehicle launch. However, we are very encouraged by this development, and we also think that it is important to continue to share our findings in real time, as we have with other aspects of the Volt's development."
About Chevrolet
Chevrolet is one of America 's best-known and best-selling automotive brands, and one of the fastest growing brands in the world. With fuel solutions that go from "gas-friendly to gas-free," Chevy has nine models that get 30 miles per gallon or more on the highway, and offers three hybrid models. More than 2.5 million Chevrolets that run on E85 biofuel have been sold. Chevy delivers expressive design, spirited performance and provides the best value in every segment in which it competes. More information on Chevrolet can be found at www.chevrolet.com. For more information on the Volt, visit http://media.gm.com/volt/.
General Motors Company, one of the world's largest automakers, traces its roots back to 1908. With its global headquarters in Detroit, GM employs 235,000 people in every major region of the world and does business in some 140 countries. GM and its strategic partners produce cars and trucks in 34 countries, and sell and service these vehicles through the following brands: Buick, Cadillac, Chevrolet, GMC, GM Daewoo, Holden, Opel, Vauxhall and Wuling. More information on the new General Motors Company can be found at www.gm.com.
Reader Comments (Page 1 of 4)
JustZisGuy 12:15PM (8/11/2009)
This is asinine. The number is completely meaningless. Those drivers who never put fuel in it will achieve "infinite" miles per gallon, so why not say 5,000 mpg, or 10,000 mpg, or 100,000 mpg?
Unfortunately it seems that the media takes this 230 mpg figure at face value, stating that it is many times better than the Prius. But of course the only gasoline rating that makes any sense for comparison is the "no charging" use of the car. I suspect that figure would be close to that of the Prius (it would actually be interesting to learn whether it is better or worse).
There should be two figures: the above "no charging use" mpg and an electric use figure.
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once loved cars 12:59PM (8/11/2009)
I believe the EPA number takes into account the amount of electricity put into it.
http://en.wikipedia.org/wiki/Miles_per_gallon_of_gasoline_equivalent
This is not an inconceivable number. The Tesla gets 135MPGe
JustZisGuy 2:31PM (8/11/2009)
Yes, 230 mpg gasoline equivalent is an inconceivable number for a 5 seat sedan. Period. End of story. You might as well tell me that an airliner could get 200 seat-mpg - sorry, dude, they've been working on it for decades and the best they've been able to do is about 70 seat-mpg.
Use your critical faculties: how on earth could there be an order of magnitude improvement in efficiency, in a car which
a) weighs about the same as similar-sized cars
b) has similar aerodynamics to its competitors (it's certainly not half the drag, or anything close to revolutionary)
c) uses good old rubber on asphalt/concrete
The laws of physics must be obeyed.
For what it's worth, I love the idea of an ER-EV (almost as much as the idea of an EV). The Chevy Volt is no doubt very efficient, but please, tell us the real number, not some fantasy number which includes unmeasured amounts of energy via recharging the battery.
This whole thing is really a smokescreen to smother the fact that the price of the car is now estimated to be $40K, rather than $30K.
Snowdog 2:37PM (8/11/2009)
Once loved, your number proves that the GM hype number doesn't even count electricity as anything. A Roadster uses less watts/mile than a Volt, so there is no way for a Volt to get 230 eMPG if a Tesla gets e135mpg.
Clearly the calculation uses some number of free uncounted electricity miles and a few token gas miles. Then ignores the electricity input when calculing mile/"gallon".
It is a complete nonsense hype number.
JustZisGuy 2:44PM (8/11/2009)
I should add, in passing, that the Tesla number is phenomenal. It demonstrates the efficiency possible from a pure EV. When burning gasoline, obviously, the Volt cannot compare in efficiency because the efficiency of a (really efficient) internal combustion engine is on the order of 1/3. That's where the big loss is.
Please also note that the Tesla only has two seats. So, while it may appear incredibly efficient if you're comparing single drivers or two people per car, it becomes less so when compared against cars with all their seats filled. Heck, a Ford Explorer roughly matches it in efficiency - if you're comparing the Ford with 7 people versus the Tesla with 1.
Domenick Yoney 12:20PM (8/11/2009)
Just for a little perspective, the EPA rates the Tesla Roadster at 33 kWh per hundred miles in city driving. Compare that to the Volt's EPA estimate of 25 kWh per hundred miles. Could the Volt be 32 percent more efficient?
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polo 12:40PM (8/11/2009)
Umm higher kw doesn't mean the car is more "efficient" it means the car has longer ranger.
Gwido 8:18PM (8/11/2009)
Where did you get your number from, Domenick? I didn't find the Tesla Roadster on fueleconomy.gov However some other EVs like Toyota RAV4 and Nissan Altra have a city efficiency of 27 kWh / 100 miles, which is almost as good at the Volt.
According to the Tesla website, the Roadster consumes 110 Wh/km, which gives approximately 17.6 kWh / 100 miles
PopSmith 2:54PM (8/11/2009)
I don't know which is more efficient, however, the 2008 Tesla Roadster uses 29 kWh/100 miles in the city and 32 kWh/100 miles on the highway, according to it's sticker.
Ernie 3:26PM (8/11/2009)
Yeah, actually I suspect that a family sedan could be a tad more efficient than a sports car. Is that *really* so hard to imagine?
On top of that, electric motors are much more efficient than gas motors. The greatest inefficiencies in the volt are converting between mechanical and electric power and back, but you get some of that efficiency back by:
1) regenerative braking
2) running the gas engine at peak efficiency all the time, rather than 10% of the time, as with what happens during the normal driving cycle (especially city driving).
Domenick Yoney 3:31PM (8/11/2009)
Thanks Pop, I was looking at the wrong sticker. Measure twice, cut once. measure twice, cut once.
Nateb123 4:55PM (8/11/2009)
Actually the Volt is more efficient. kWh/miles is a measure of how much work is done over a distance. So the Volt does less work than a Tesla which makes sense. A Tesla is set up for speed and drags Li batteries with it while a Volt is set up for economy.
@polo
I still haven't seen your brainless, eco-yuppie fingers type one meaningful sentence in all my time on autobloggreen. It's clear you just talk to talk because you have no understanding of even the basic units used by engineers. You just flat out don't know what they mean yet you seem to think you know the solutions to the world's car problems. Read a damn book before you think your opinion is worth as much as the bits it takes up. kW =/= kWh. I'd say that's like saying torque and horsepower are the same but that's an analogy I'm sure you won't understand.
Speculawyerr 12:21PM (8/11/2009)
I like the EPA rating system. If people plug-in every night (as they should), this is an accurate assessment. And the very large number will accurately portray how a series-hybrid can allow people to drive without needing gas very often.
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Jacob 12:39PM (8/11/2009)
This is completely inaccurate. One day, you might drive 30 miles, using no gasoline at all. The next day, after a charge, you may drive 75 miles. Then, the 230 MPG rating may be accurate. But a week later, you take a vacation and drive 700 miles. You won't be getting 230 MPG on this trip.
Ignatius 12:48PM (8/11/2009)
Does everyone travel 700 miles suddenly? No, most people commute to work and back and that's it.
They're looking at average use, not the extremes. The average driver will go to work, come home, plug it in, then go back to work, come home, plug it in.
Snowdog 2:42PM (8/11/2009)
"Does everyone travel 700 miles suddenly? No, most people commute to work and back and that's it."
Then they are much better off with a pure EV like a leaf, rather than hauling around a complete fuel/exhaust/ICE they will never use.
But it isn't about the details of usage patterns. There is a principle here that GM is violating, that of honorable, transparent behavior.
Does the new GM really want to emerge from the blocks appearing misleading and deceitful. Because that is how it is looking to many.
I had high hopes for new GM and they are disappointing me in a big way with this behavior.
Matt 4:37PM (8/11/2009)
I agree with Ignatius. Most of the time, most people will plug the car in every night, and barely use gasoline during the week.
Last I checked, the average person drives about 12,000 miles a year. For the sake of argument, lets say that 90% of people drive less than 15,000 miles per year. If that 15k is spread evenly, that's roughly 41 miles a day. If the Volt can go 40 miles on a charge that would only be one mile of gas per day. More likely, 90% of people drive much less than 40 miles, and it's more like 30 miles on week days and 137 miles on a weekend trip (or just not perfectly spread out over every day). So, if you plug in every night, but go for a trip on the weekend you'll use only about 1.14 gallons if the car gets 50 mpg on the generator (41x7=287, 30x5=150, 287-150=137, 137/2=68, 68.5-40=28.5, 28.5x2=57, 57/50=1.14). That's 287 miles ÷ 1.14 galons = 251 mpg by my calculation, but then again I don't have the actual statistics... This is a totally plausible mpg average, though.
On the other hand, they could just give us the mpg for the generator and let us figure out our own consumption averages.
surfmonkey54321 7:17AM (8/24/2009)
I too tend to like what I am understanding about the EPA numbers. But having been reading the posts between the "regulars" I see here, there seems to be some bad blood, or "I'm smarter than thou" going on where simple speculation is all that is available at the time. I saw one expressing concern of deceptive practices by GM, when the article that I just read merely states that the EPA is working on a formula by which to measure apples to apples in this semi-uncharted territory. The way I read it, it's EPA coming up with the formula to rate the various offerings, not GM being deceptive. And a simple comment made by an individual demonstrated a very anal and mean spirited attack by the same conspiracy believer that GM is being deceptive. For the record, I drive a Prius, mostly alone 5 days a week on the freeway 112 miles round trip. I'm not interested in driving like an idiot on the bumper of a semi truck, as I am seeing the results of that horrible emotional wear on a very safe truck driver that works for me, and who lives with the fact that a "smart" engineer piled his car into the bumper of our trailer and lost his legs from above the knees down, nearly killing him so he could save $.47 per trip per day and bragging rights. I doubt that Don will ever be the same after 27-years of accident/injury free truck driving all over our country because of the actions of an unsafe "hypermiler" playing NASCAR. Unlike most, I drive my commute daily and twice monthly take a weekend trip to visit my daughter, a 740 mile round trip drive. I have followed the Volt closely as I contemplate making the vehicle change when it's available. Those of us in management with company Hybrid cars can plug in if they have one capable of such technology. My Prius does not fall into that category however. I do well in mpg using climate control, xm radio, and cruise control. This means that I would exceed the 40-mile battery range by 16 miles each way, buying 32 miles worth of fuel per daily commute. Again, it appears that GM is doing just fine, and the focus of this article was EPA coming up with an apples to apples formula for rating efficiency. I came away from those mean spirited comments thinking the poster likely forgot to take his meds that day, and that he likely believes in invisible UFO's using a magnetic force to pull his car along to help acheive better mileage. All of you are far smarter than I am in this transportation design field, but come on ladies and gentlemen, the personal attack I read and the "I'm superior to your thinking" attitude was really not called for, but being related to an "engineering type" I understand the attitude. Maybe his pocket protector leaked his KY-filled disguised pen into his shirt and he had to go home to Tondra, have her put down the bon bons to get the mysterious stain out between dvr taped soaps from that day. In my view, we are all in this to advance green technology for our commutes, and share in the information that we come by along the way. My reciprocation of his attitude wasn't nice; an example of what it came across like and to the rest of you, I'm sorry. I'm looking at another alternative if our company approves them as company cars, and if it pans out I will gladly share anything that I learn from the experience with all of you because I have seen no mention of this vehicle in any posts. I do know that our "Toyota days" are coming to an end soon and I have to get rid of the most fun car I have had in 36-years of driving. Anyhow, good day to all of you. Mikee
oollyoumn 12:25PM (8/11/2009)
This looks very deceptive at current prices. If it cost $2.75 to go 100 miles, how do they get 230 mpg? A gallon of gas cost me less the $2.75, so this should be rated at less than 100 mph.
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Chris M 5:39PM (8/11/2009)
The price of gas here is $2.89 a gallon, would that mean a different "fuel economy" figure? No, changing the price of fuel doesn't change the fuel economy figures, so just because electricity is a lot cheaper than gasoline doesn't affect the fuel economy of plug-in hybrids.
But it does make a big difference on the economics involved.