Home > General, Markets, Politics > Chevy VOLT versus a horse & buggy

Chevy VOLT versus a horse & buggy

August 11, 2009

chevy voltGM says that its new Chevy Volt gets 230 miles per gallon (using EPA test methodology).  Using the same methodology, Rocky’s wheelbarrow gets over 1,000,000 miles per gallon. 

Statistics don’t lie. Or do they?

Here’s the math (converting electricity to gasoline).

The Volt’s 350 pound battery pack generates 16 kwh or 57,776,000 Joules.

One gallon of gas = 1.3 x 10^8 Joules, which converts roughly to 0.444 gallons/hour (energy equivalent.)

So, if you are driving 50 miles per hour, the electricity consumed equates to about 22.2 miles per gallon of gasoline.

The Volt’s retail price will be about $40,000.  And average electricty prices are 15¢ per kwh. So the electricity bill will be about $2.40 for every hour of operation.

It’s reasonable to expect that the Volt’s cost will decline,  and its efficiency will improve over time.  It’s also reasonable to expect that if electric cars become popular, gasoline prices will decline and electricity prices will rise… creating a less favorable equilibrium.

Rocky concludes that absent an important breakthrough in battery technology (or massive government subsidy,) the Volt will be an expensive novelty — and not a commercial success. Even if it gets 253 miles per hour. See: Bugatti Veyron.

[Disclosure: Rocky drives a car that gets 32 mpg on the highway,  and his desk chair gets really good “gas” mileage too. Toot, toot.]

  1. August 11, 2009 at 3:57 pm

    Pedant: I think you mean kw-hour (or “kw hour”) not kw/hour (kw per hour is some sort of rate of increase of the rate of energy consumption.)

    The real cool number is the mpg for the volt if you drive less than 40 miles between charges. It’s INFINITY! Now I’m just a poor man’s theoretical physicist/computer scientist, but anytime I see infinity, I know that the number I’m calculating must have some problems 🙂

    The real question is how the GM spokesperson got the $0.40 number for charging the damn thing. Lies, damn lies, statistics, and PR folks, I think.

  2. August 11, 2009 at 4:04 pm

    Thanks Dave. Rocky will fix that typo. Does the other arithmetic look approximately right?

  3. August 11, 2009 at 5:53 pm

    I think your orders of magnitude are close but I’m not sure the conversion from the battery pack power to the real numbers works out and the conversion straight from gallons to energy needs to take in the fact that engines aren’t perfectly efficient (20 percent?) GM is saying 25 kilowatt hours/100 miles electrical efficiency which is a factor of 2 from what you have, which is pretty close.

    Anyway the real problem is why would I pay $40K (-$7.5K rebate?) for something whose cost savings won’t be so much better than a Prius. Of course the reason people will give is that electrical energy is “cleaner” than gasoline (this depends, of course, on where exactly that electricity is coming from. Doing lbls coal / mile is not going to make you too happy, I think), but is it worth the $12K premium? Well it seems that GM has always thought they were worth that premium 😉

    I’d be skeptical of my mom going for this, but man when I talk to kids today they are ALL over environmental impacts, so I’d guess they might have a market for young professionals (Universities these days are Prius parking lots. Funny assistant profs get the first stable salary of their lives and almost universally go out and buy a Prius.) Me if I’m going to go eco-cool, I’d want the Tesla (they just opened a shop in Seattle.) http://www.teslamotors.com/

    Also: I can guess what part of the country you live in via your estimate for average electrical energy costs 🙂

  4. August 11, 2009 at 8:41 pm


    Having done the arithmetic repeatedly, gasoline needs to average well over $6 to even get close to justifying the cost of a Prius (versus a regular Civic or Corolla).

    It’s about making an eco “statement” — which is what free markets and choice are all about.

    As for the $100k Tesla Roadster, Porsche’s engineers are not losing any sleep (yet).

  5. August 12, 2009 at 12:21 am

    Re: Prius cost. Even with the new solar powered air conditioner for when you are away from your car? Heh.

    Indeed Tesla is no Porsche killer. But Porsche hasn’t gotten nearly half a billion in low interest loans (http://www.bizjournals.com/pacific/stories/2009/06/22/daily33.html) so who knows.

  6. August 16, 2009 at 12:27 pm

    I thought I read months ago that the 200+ MPG was calculated based on how much gas would be used in say a year since it is normally running on electricity. Most folks will not drive over 40 miles a day. I don’t.

    In my case, I’d drive 20 miles roundtrip M-F for work commute. Then let’s say on Saturday I drive 100 miles one-way out of town. I use gas for the last 60 miles each way, assuming I charge it before leaving Sunday. So I’ve driven 300 miles that week total and used maybe 3 gallons of gas for 100MPG average over the week. If I’m not going out of town each weekend, then overe the ong run that average MPG may very well be 200+.

  7. August 31, 2009 at 5:31 am

    Great Post.Good Content, I like your post very much, It is useful for me.

    Thank you

  1. August 13, 2009 at 6:26 pm
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