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Why the 2011 Chevrolet Volt EPA Rating Sends Mixed Messages

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Volt Fuel Economy Sticker

Volt Fuel Economy Sticker

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If like us, you were waiting with baited breath for the official EPA rating for the 2011 Chevrolet Volt you’ll have heard that the day before Thanksgiving Chevrolet announced the official figures were back for its first plug-in range-extended electric car. 

But unlike the 2011 Nissan Leaf’s figures, which caused a lot of controversy but were vaguely straight-forward to understand, the EPA rating for the Volt was somewhat more confusing.  

Apples to oranges

When the EPA rated the 2011 Nissan Leaf it had just one comparison to make: what the equivalent miles-per-gallon would be if one gallon of gasoline was equivalent to 33.7 kilowatt-hours of electricity. 

Called Miles Per Gallon Equivalent (MPGe), the figure is aimed to give car buyers unfamiliar with electric cars a tangible way to view fuel economy. 

2011 Chevrolet Volt test drive, Michigan, October 2010

2011 Chevrolet Volt test drive, Michigan, October 2010

Enlarge Photo

While the comparison caused some lifted eye-brows and cries of anguish from those of us who felt comparing electric cars using gasoline was a little like comparing dogs to cats, the figures for the Leaf were relatively straight forward: 99 MPGe, and an official EPA-sanctioned range of 73 miles per charge. 

Not so for the Chevrolet Volt, which is capable of all-electric travel as well as gasoline-assisted travel.  The EPA rating reflects this, with a dizzying array of figures. 

All electric: 93 MPGe, 35 miles per charge 

Examining the electric-only operation of the Volt, the EPA concluded that its electric-only economy was 93 MPGe, and that it could travel for 35 miles on a single charge. 

Compare that to the 2011 Nissan Leaf’s 99 MPGe and 73 mile EPA range, and the Leaf looks to have the winning edge.

That is, if you only want a purely electric car. But the Volt’s strength lies in its range-extending gasoline engine. 

MPGe and MPG

Leaving aside the arguments about nomenclature, the Volt is capable of powering its wheels directly using the gasoline generator, but for the most part uses it as a range-extending device, providing electrical not mechanical energy to power the car’s electric motor. 

Expressing the Volt’s fuel economy in this mode proved to be extremely tough for the EPA. After all, with a semi or fully discharged battery, the Volt actually uses gasoline, right?

The worse-case fuel economy, for all-gasoline motoring? 37 MPG, leaving consumers with at least a basic concept that using the Volt in plug-in mode is eminently better than using it in gasoline-only mode. 

Throwing in a third figure, the EPA rating concludes the Volt’s combined fuel economy is somewhere around 60 mpg for regular use - that’s using a combination of gasoline and electric powered driving. 

Multiple figures, confusing sticker

2011 Chevrolet Volt test drive, Michigan, October 2010

2011 Chevrolet Volt test drive, Michigan, October 2010

Enlarge Photo

The EPA didn’t stop at worse and best case scenarios. In a box on the Volt Fuel Economy Sticker, the EPA have listed example fuel economy figures based on a set distance driven. 

This is when things get really screwy. 

Listing trips of between 30 and 75 miles between charges, the EPA details corresponding fuel economy figures, using MPG and electricity consumed as two discrete lines on its chart. 

For example, driving 45 miles between full charges will result in 12.9 kilowatt-hours of electricity being used. It will also result in a gasoline fuel economy figure of 168 MPG. 

Yes, a fuel economy figure of 168 MPG, greater than the 93 MPGe of the electric only mode. But remember that the electric mode is measuring an equivalent, not an actual consumption. 

2011 Chevrolet Volt

2011 Chevrolet Volt

Enlarge Photo

There has to be a better way

The 2011 Chevrolet Volt is a great car and offers people the chance to drive electric without suffering range anxiety or requiring them to own a second car for long-distance trips. But the EPA stickers do not reflect this. 

We think it’s time that the EPA revisited its fuel economy labels. The Chevrolet Volt sticker is a confusing mish-mash of different figures, varying scenarios and mixed messages. 

To the uninitiated, it would almost appear better to drive the volt for 45 miles without recharging and use some gasoline instead of driving on electricity alone. 

Chevrolet aren’t to blame.  The EPA are. And we need a fix quickly.

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Comments (9)
  1. What is kind of interesting is GM had to use 61% more of their battery to get the listed EPA electric range. Based on these numbers, the Volt would only get 21.7 miles from the original 8kWh.
    The EPA EV range calculations seem pretty conservative. It seems like there may be some adjustments in the EPA system that maybe don't apply well to electric vehicles and plug-in hybrids:
    http://www.epa.gov/otaq/cert/mpg/420r06017.pdf
     
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  2. I disagree strongly with the article. I think the EPA has done a fine job of providing all the useful info you could want.
    I am very glad they did not go with the A,B,C rating that was proposed, too simple. The only point I agree with is a small quibble about the combined mileage being greater than either of the separate mileages, as they chose not to include the cost of electricity and those figures are for gas only.
     
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  3. What happened to the 230 MPG that GM was so proud of a few months ago?
     
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  4. I think Nikki has been kind to the EPA quoting Apples to Oranges. I think Apples to Aardvarks is more appropriate. I don't think anyone, including the EPA can produce a single unifying number that represents the 'niceness' of a car, especially when they have dual power trains running on two different fuels. The same issue applies to bio-diesel or E85 compatible cars too. And, I don't think that they should.
    We have two pieces of information that the consumer is interested in: Cost to run and environmental impact. It's time that we faced up to the true well-to-wheel impact of gasoline cars and put that on the sticker, not just the tailpipe emissions. Whilst you're at it, throw in the medical costs for supporting the sick suffering from asthma. Do the same for EVs and put up the numbers for CO2 emissions and fuel consumed: gasoline, diesel or electricity; the buyers can figure out the cost to them from that.
     
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  5. shouldn't the Leaf have a 198 MPGe rating if they have double the range????? I hate the way figures get munipulated. Why compare hybrids angainst electric cars!
     
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  6. Are the e-range only figures tested in Summer or Winter or somewhere in between? What I am getting at was the AC or the Heater (electric) plus the radio on or all off? Personally I would be very interested in an all electric auto carying 4 passengers that hsa a range of 250 miles with the AC on. This would get me to Richmond, some driving around doing errands and return home w/o worring about range. I would $55,000 for this fantasy auto.
     
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  7. Has anybody heard of the Tesla Model S? The base version has a 160 mile range and costs 49k. The next step up is 260 mile range for 10k more. The premium version has a 300 mile range and a bunch of extras for 20k above the base price. I think your dream car is the Tesla Model S with 260 mile range.
     
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  8. The phrase "baited breath" is usually spelled "bated breath".
     
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  9. @ValFitzAndrew.... take a look at Tesla Motors. The Model S has everything your looking for and more.
     
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