AUG 11

230 Miles Per Gallon – The Chevy Volt

Written by on August 11, 2009

230mpgSo a while back we published an article entitled arguing that the Chevy Volt could, in fact, get a million miles per gallon, depending on how you drive it. Since the car gets 40 miles per electric charge before the internal combustion engine ever kicks on, so if you never drive more than 40 miles from your house, you never use gas…at all.

Of course, there has been some worry about how mileage ratings would be given to such a car. Well, the mystery is over. The EPA has developed a new system to determine the efficiency of plug-in vehicles, and the Volt came in at 230 mpg in the city and 100 mpgon the highway. This makes it the first car to have a triple-digit mileage rating.

The new calculation is more than just a guess by the EPA. The driving habits of Americans are taken into account, of course, but so has the petroleum equivalence of the electricity used to power the car. So they didn’t just call those first forty miles “free” they took into account the cost and environmental impact of the electricity and it’s STILL 230 mpg!

It’s a great day for automobiles my friends.


14 Responses to “230 Miles Per Gallon – The Chevy Volt”

  1. Bob Wallace says:

    Any chance you’ve picked numbers to make your math work? Or that you’ve set up formulas to get the result you’re after?

    (Not that I’m accusing you of being a bad person, just that reality might differ.)

    Problem here is, we don’t know the EPA/DOE formula which, I understand, both GM and Nissan are using to gen their MPG numbers.

    What if the number comes from:

    1) 85% of driving electric only + (15% of driving > 40 miles – 40 miles of charge) = X amount of gas to be purchased.

    2) All that electricity which covers > 85% of driving is equivalent to Y amount of gas to be purchased.

    3) Miles/(X+Y)=MPG.

    I’m not ready to believe that GM is ignoring the purchased electricity component in their math. I think it’s more likely that there are things which we don’t yet know.

  2. Joe says:

    If what you’re saying is true, Nissan’s Leaf’s 367 mpg is an honest figure. It translates electric usage to gasoline equivalent.

    Chevy is completely ignoring the electric, the electric charges’ cost, and its impact on the environment. They thrust it out in advertising as if for every gallon of gas you use, you get an extra 180 emissions-free miles worth of driving free from some magical electric source that drops down from Heaven. It’s 50 mpg + 40 miles per charge, that’s what their site says. If they were honest about it, they’d either be claiming that up front or they’d be using the less simplistic formulas that the all-electric vehicles use for mpg. My guess is the reason that they don’t use those formulas is that they would render a much lower number than 230. Anyone got a formula that an all-electric uses?

    On the FAQ, they say that “How many miles per gallon will the Chevy Volt get?” is “A bit of a trick question.” In the ads they simply say 230 mpg, before we deceitful consumers even get to even ask our “trick question” and they follow it up with 0 footnotes until you get to the FAQ. It’s a load of greenwashed advertising bs and it’s their headline.

    I will concede about the few percentage points, though. I was looking at someone else’s and not gm’s figures when I first did the math. It’s more like 21% more range gets their mpg into the thousands.

    230 miles = 50 miles(1 gallon of gas) + 180 miles electric
    180 / 40 miles per charge = 4.5 charges in 230 typical miles
    50 miles/4.5 charges = 11.1 miles on gas per typical charge

    So, they must be figuring the average distance driven per charge is about 51.1 miles. If it could drive 51.1 miles(27% more than 40) on a charge, by their logic, they could claim infinite mpg.

    Anyone want to check my math?

  3. Bob Wallace says:

    [i] It seems pretty obvious that the picked the number first and adjusted the car or the math accordingly.[/i]

    They picked the number first and adjusted (designed) the car accordingly.

    GM and Toyota collaborated on a study of American driving habits several years ago. Before the Volt was designed.

    They determined that 85% (?) of trips are less than 30 (?) miles. The question marks are because I don’t remember the actual numbers, they might be somewhat different, and I couldn’t find the info with a quick search.

    [i]… increased the range on a single charge by a few percentage points, they could have easily claimed an mpg in the thousands[/i]

    I don’t think so. The energy used for electric-only miles are translated into ‘gas that would have been burned’. If we look at the MPG projected for Nissan’s Leaf which is all electric/no liquid fuel, we see 367 MPG.

    [i]230 mpg is total greenwash.[/i]


  4. Joe says:

    from their own site :

    [i]Q: How many miles per gallon will the Chevy Volt get?
    A: A bit of a trick question. For the first 40 miles it will get infinite mpg, because no gas will be burned. When the generator starts, the car will get an equivalent of 50 mpg thereafter. One can calculate the average mpg per for any length drive starting with a full battery: Total MPG = 50xM/(M-40)[/i]

    If they would have increased the range on a single charge by a few percentage points, they could have easily claimed an mpg in the thousands, but that would look absurd. It seems pretty obvious that the picked the number first and adjusted the car or the math accordingly. By their own admission, the number makes absolutely no consideration for the electricity to charge it. It gets 50 mpg, plain and simple. 230 mpg is total greenwash.

    Hey, I bought a villa in France for $0. Yeah, I paid in Euros.

  5. lee says:

    Yikes. I give up.

  6. Bob Wallace says:

    Lee, you’re flailing around in a rather meaningless manner.

    Averages are exactly what they report to be – averages. Averages are useful if one knows how to use them.

    The EPA (apparently, I haven’t found a full description of their methodology) took the performance characteristics of this hybrid, looked at how much of the mileage will be done on electricity alone and how much will be done using petroleum and then did the math.

    We know the percentage of electricity produced by coal, hydro, natural gas, nuclear, wind, etc. and the environmental impact of producing electricity with each of these methods.

    This is all basic math.

    And “cost” as in charging cost, cost of gasoline, has nothing to do with the MPG rating.

    I really don’t care that you’re not average. You could be above average or you could be below average. But add us all up, divide by the number of us and that’s our average.

    We Americans drive an average of 12,000 miles per year. I drive about half that much. Obviously someone else drives more to make up for my lack of driving.

    It averages out.

    If you’re interested in buying a Volt then you need to take the 230 MPG and see how it fits your particular situation.

    You might drive a lot more than 12,000 miles per year, but you might hardly ever drive more than 30 miles between charges. You might drive 30 miles to work, plug in there, drive 30 miles home, and plug in there.

    You might get far better than 230 MPG equivalence. You might never buy gas.

    I happen to drive more than 100 miles almost every time I leave home. I’d get about 30 miles on electricity and then switch to fuel. I’d get much less than 230 MPG based on my driving style.

    But all of us together would average out around 230 MPG.

    And that 230 MPG would allow us to make a reasoned comparison to another car that had, say, a 180 MPG rating.

  7. lee says:

    No it’s not. There’s a difference between mean and median and a meaningful estimate. And your conclusion assumes that the car will sell equally across the country. It seems more likely that the car will sell more frequently in high population areas (both because of more people and lower travel distances) than it will in lower population areas, in general those high pop areas have higher energy costs and are disproportionally powered by coal. And while you are asserting that the 230 is just a number that estimates the impact of all cars, that’s absolutely not what its for. It’s an ad campaign by GM. “Our car gets 230 mpg, so buy it.” It doesn’t get any more personal or individual than that. As your later article indicates, there are far more meaningful numbers for environmental impact that mpg. If its about average impact across the nation we’d be using those numbers and we’d need actual estimates of sales across the country as well. It’s not about that, it’s about marketing an individual car to an individual buyer. It’s about stickers on windshields and comparing to other cars. And the comparison of a VOLT against a VW Jetta diesel in San Francisco and between the same vehicles in Spokane is an entirely different comparison, both in terms of cost and impact.

    The 230 mpg number is greenwashing plain and simple.

    Averaging the cost and impact across the country is meaningless. I don’t live in Average and neither does anybody else.

    If it’s 105 degrees in Phoenix and 60 degrees in Flagstaff. It’s incorrect and meaningless to say the temperature in Arizona averages 82.5 degrees. It’s either 60 or 105.

    Cost alone is ridiculous to average. Impact is downright crazy. Environmental impact of hydro power is unquantifiable. You’re talking about impact on fish and watersheds, irrigation and farming. It’s mind-bogglingly complex. You can’t translate it into petroleum equivalence.

    The EPA should either publish a straight mpg minus charging costs and tell consumers that, or it should create a new rating system for EVs that actually compares them.

  8. Hank says:

    Just finishing a write-up on the larger issues here. But Bob is right, the EPA doesn’t care what the emissions of YOUR car are…they want to know the emissions of ALL cars. So, for a car that will sell in (and use electricity from) all fifty states, they can just use the national average and get data that are fairly accurate.

  9. lee says:

    No you can’t. That’s a ridiculous assertion. the environmental impact of hydro power, nuclear power and coal is entirely different. Power is cheap and plentiful here in central Washington. Not so much in southern California. Neither the cost or the impact of a kWh of electricity across the US can be generalized about in a meaningful way.

  10. Bob Wallace says:

    Lee – thought so. Just slinging stuff from the hip in an attempt to look smart?

    The amount of energy in a kWh of electricity and a gallon gas don’t vary over regions.

    Then one can measure the environmental impact of generating electricity over the entire country and come up with a good average based on methods and percentages of generation.

    This stuff is known.

    Sure, there will be individual differences. The stated number is a projected average.

    And you can say that the US is hot in the summer as compared to the winter.

    That’s pretty meaningful, while also only averages.

  11. lee says:

    Regardless of the methodology, it can not answer my concerns. Electricity in the US cannot be converted into any meaningful “petroleum equivalence” because of regional variations in electricity production.

    It would be like saying “the weather in the US is hot.” It’s too large and varied a thing to generalize about in any meaningful way.

  12. Bob Wallace says:

    Lee and Fred –

    1) Did you actually read the EPA methodology for determine gas equivalence?

    2) If so, where did you find a writeup of their methodology?

  13. Fred says:

    What fantasy world are you living in?
    In the computer business, we have learned to call this kind of ridiculous claim “vaporware”. And we know better than to spout off nonsense about what a great day it is just because some government flunky decided to dump a fresh load of BS on our doorstep.

    Hank, get a grip, man. Stuff like this is bad for your credibility.

  14. lee says:

    Not Exactly
    The assertion that they have taken into account petroleum equivalence is ridiculous.

    Depending on your location, prices and environmental impact of grid electricity varies dramatically. To stick one number on it is incredibly misleading.

    But that’s unfortunately consistent with a lot of other government issued reports and evaluations that are dumbed down for the general public and skewed for political correctness.