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Sometimes Wrong but rarely in doubt!

14 August 2009

The Chevy Volt 230mpg - Sorta

Does the media and and advertising executives really think that J.Q. Public is dumb?

I have to think they do. The Chevy Volt and it's claim of 230 mpg is an excellent example of the media's underlying assumption about the masses (of which you and I are a part). Work is a ten mile drive for me, given the Volt's purported 32 mile all electric drive range that means that if I faithfully plug it in I should never hear the 1.4L engine ever start up during my normal weekly usage. Do the math and I get a lot more than 230 mpg during my daily commute. But math, like logic, is just a way of being wrong with confidence. The correct expression of it's mileage should be in terms of each of the energy sources it can utilize mile per gallon and miles per kWh. But is the Chevy Volt really much of an improvement? I couldn't find enough information to express it's mileage in a meaningful way so I've taken a different approach to analyzing the Volt. I'm going to compare the Volt to my Mazda 3. I'm going to spend a moment defending my car comparison, I picked the Mazda 3 because that cars are roughly equivalent in terms of size and utility as far as I can glean on the internet. It's apples and apples, the apples just might be Red River and Crab apples but that's up to the reader's judgment.

The Green Case:

The the only info I could find on the Volt indicated that the gross vehicle weight was 3520 pounds. In comparison my Mazda 3 weighs in at 2810. The other difference between the cars are small. The difference in effective projected area between the two cars is one square inch (.025%) which I feel is negligible. I'll reasonably assume that the coefficient of rolling friction is the same (same tire's difference in bearings negligible). What does all this mean? Getting me to and from work requires more energy using the Volt than it does using my Mazda Three by virtue of the extra 710 pounds of gross vehicle weight I've got to haul around. Most of that energy still comes from fossil fuels sources so if you accept the CO2 forcing hypothesis then the Chevy volt is not likely to be a green choice.

As we saw with the Smartcar vs Ford Freestyle post, the fuel efficiency is just one part of the overall efficiency of a vehicle but let's examine that anyway.

The Economic or Business Case:

What are the pluses of the Chevy Volt? I'm dodging fuel taxes and levies because I'm substituting electricity for fuel for the 32 mile range of all electric operation. Since I drive about 150 miles per week let's compare the cost of operation of the Chevy Volt versus my Mazda 3.

About 90% of my driving is highway driving so I'll use 150 miles/week highway driving for my analysis. Straightforwardly the stated highway mileage for my car is 47.9mpg, cost of operation for one year is $585 of fuel per year ($0.949 per litre). Let's look at the Volt, now I'm going to make some assumptions about gas vs electric operation, let's assume 100 miles of all electric operation and 50 miles of gas operation. I'll also have to assume a gas operation mileage, for the sake of argument and ease of calculation let's assume that it's the same as my Mazda 3 so the cost of operation is one third that of the Mazda plus the electrical usage. The electrical cost is 30kWh per week, let's go all out green and use a local green energy provider, which increases the cost of a kWh from $0.10 to $0.14 per kWh, thus the cost of operation is $405 per year. The difference in price between the Volt (40K CAD) and my Mazda (16K CAD) is about $24000. Thus it would take 133 years to pay off the difference in price with the improved fuel economy, hell let's throw in the 10K CAD grants the Ontario government is bandying about, that reduces it from a century and a third to a mere three quarters of a century. If I assume that I never buy gas for the Volt that changes the payoff period to 70 years without the grant and 40 years with the grant.

The low mileage case I've used might not be a good example so let's up the ante a bit, at 20,000km per year or 12500 miles the pay off time is still 27 years and the life of the car is realistically about 8-10 years. If I'm buying a car and I want to offset a higher price for better mileage or 'greeniness' then the savings due to improved mileage need pay the difference in less time than the life-cycle of the car.

There is no good business/economic case for buying the Volt.

Preaching from the Pulpit:

Nothing has changed with the advent of hybrids, we've only incrementally improved mileage. The Volt is nothing more than verdigris smoke and jade mirrors. Gasoline, propane, natural gas and diesel fuel all provide concentrated forms of energy in light and portable forms. Until battery technology improves to the point that the energy density approaches that of gasoline we are up against a barrier to improved efficiencies for auto transport. Even Honda's hydrogen fueled FCX Clarity doesn't alter the equation more than incrementally until we begin deriving our energy from something other than fossil fuels.

Frankly until western society starts providing a better education in science, mathematics and critical thinking we are going to continue to experience the outbreaks of mass hysteria about junk science. Often the comment is made in discussions about AGW that even if the greenhouse hypothesis is wrong shouldn't we be embracing these technologies anyway. That statement is at best a half truth. The problem with western's society's current fascination with eugenics Piltdown Man The Tasaday Tribe Lysenkoism atmospheric carbon is that it distorts research and development. The reasons you are doing something distort the solutions you'll choose and it's easy to make a misstep and choose the less than optimal solution because the underlying reasoning is unsound. The Chevy Volt is a good example of of a less than optimal solution to improving fuel efficiency both for the business case and the green case.


Peter Foster published an editorial in the Financial Post that makes many of the same points. I should note that the consumption in all electric operation is 25kWH rather than the 30kWh that I used above. That will reduce the time needed to recoup the costs but still will not alter the basic fact that for average J Q Public the Volt is not economically viable.

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