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Automobile energy cost - Dust to Dust report

  1. Jul 28, 2007 #1

    Andrew Mason

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    Some organization called CNW Marketing Research Inc. has published an "analysis" of the total energy consumption of various kinds of cars. It is called Dust to Dust: The Energy Cost of New Vehicles From Concept to Disposal.

    This is most certainly not a scientific paper (it refers to "gigajuelles" for example). No author is given credit. It appears to be nothing more than a marketing ploy.

    The conclusions and analysis appear to be quite absurd. For example it says that the total (societal) cost of energy consumption during the lifetime of a Toyota Corolla is $0.73 per mile and the cost of a Toyota Prius is $3.25 per mile. No explanation is given as to how this data was obtained. To suggest that a Prius will cost $3.25/mile for 109,000 miles means that the total societal cost for a Prius is $354,000. Now a Prius might cost about $30,000 and at 40 mpg (mine gets about 44) it will consume about 2725 gallons. At $3 per gallon (the figure used in the report) that works out to and additional $8175. So even if the car lasts only 109,000 (mine is already at nearly 97000 and is still like a new car) it would cost the owner less than $40,000 or about $.37 per mile. That includes everything: materials, labour, energy etc. So how can just the energy cost $354,000? How is it possible that society subsidizes a vehicle by that much?

    Am I missing something?

    AM
     
  2. jcsd
  3. Jul 28, 2007 #2

    Danger

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    There's no damned way in the world that I'm going to read 458 pages of anything on line.
    As for the overview that you gave in your post, it's horrendously incomplete (not your fault). To start with, do they factor in the living conditions as in wage vs cost of living for the people who build the cars and provide the fuel, lubrication, antifreeze, upholstery, ad nauseum to keep it running? Then there's what percentage of vehicles on the world's roads are that model, which determines how much of the infrastructure costs are its responsibility.
     
  4. Jul 28, 2007 #3

    russ_watters

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    I haven't read the article, just the thing on 100,000 miles for the Prius (I've heard of this study before...) Their logic is horrendously flawed. The article purports to give you advice on what you should buy, but whether you buy a Prius or a Hummer, you'll likely drive it the same number of miles. The fact that early Prius owners bought it as a social statement and only drove it 7,000 miles a year doesn't have anything to do with that.

    How they come up with the "societal cost" is beyond me, but maybe I'll look into it if I get a chance. I think the Prius is sold at a loss, so it may well cost more than you actually pay for it, but my view of economics is that in general, the consumer pays all the so-called hidden costs. They mention the waste of shipping 10,000 tons of Nickel across the globe for processing, but so what? - that shipping cost is factored into the cost of the car. It has to be.

    I'm guessing they do some trickyness with waste disposal or environmental cleanup costs - perhaps assuming that eventually we'll have to dig up our landfills and recycle them or suck our CO2 out of the atmosphere.
     
  5. Jul 29, 2007 #4
    The eviromental friendliness of a Prius is a joke. The byproducts of nickel smelting and the production of nickel foam. Toyota can claim what they want about the prius, but their suppliers still dump sulfur dioxide into the air to produce the batteries.
     
  6. Jul 30, 2007 #5

    Andrew Mason

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    The question is how much pollution - and more to the point, how much green-house gas emission results from the production of the battery. A Prius battery weighs about 53 kg. (120 lb).

    A Prius getting 50 mpg over 300,000 miles will consume 6000 gallons of gasoline or about 18,000 kg and produce about 45,000 kg of CO2. A similar small car such as the Toyota Corolla will get about 35 mpg and over 300,000 miles will consume about 8500 gal. of fuel or 25,500 kg and produce about 64,000 kg of CO2, or about 19,000 kg more than the Prius.

    Are you suggesting that the production of a Prius battery creates more than 19,000 kg of CO2 emission?

    AM
     
  7. Jul 31, 2007 #6

    FredGarvin

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    Will a set of Prius batteries last for 300,000 miles? I have heard that they won't even come close.

    The Wiki article on the Prius does have a section regarding the nickel production and states assumptions that were made were in error. One of them being that it was assumed that the entire nickel production out of Inco's plant in Sudbury (near my cottage!) was for the Prius.

     
  8. Aug 1, 2007 #7

    Andrew Mason

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    The warranty is for 8 years or 100,000 miles and Toyota has stated that the battery should last the life of the car. There are not many documented battery failures. This taxi driver in Vancouver puts 100,000 miles a year on his Prius taxi and has logged over 250,000 miles (400,000 km) without any major part failure. So 300,000 miles might be conservative.

    AM
     
  9. Aug 1, 2007 #8

    Andrew Mason

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    These costs must be paid for by the wages of the workers and by the suppliers so the living and energy costs of workers and costs of the supplies are factored into the purchase price.
    The roads exist for all vehicles and are paid for by fuel taxes and general revenues. There really is not much point factoring that into the equation because the cost does not depend on the drive train of the vehicle. Smaller cars, if anything, would be responsible for less wear and tear on that infrastructure.

    AM
     
    Last edited: Aug 1, 2007
  10. Aug 1, 2007 #9

    FredGarvin

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    That really is better than I was lead (pardon the pun) to believe.

    Honestly, the only comparison that I would accept in this debate is the total amount of energy that went into the manufacture of each vehicle. If the batteries have to make 2 round trips from Japan to India and then back again, that should be considered as part of its carbon footprint, to borrow a catch phrase.
     
    Last edited: Aug 1, 2007
  11. Aug 1, 2007 #10

    Danger

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    This might be a matter of my misunderstanding your original post. I took 'societal cost' to include more than financial considerations, such as health care for vehicle accident victims (sorry, I forgot that you don't have that in the US :rolleyes:).
     
  12. Aug 2, 2007 #11

    Andrew Mason

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    If you factor in the cost of accident victims, then you would have to add insurance costs. I pay $825 a year for my Prius. Let's say the vehicle lasts 10 years. That is only $8250 and that will cover the liability for medical costs of any accident. If it was $30,000 it would add 10 cents a mile to the cost - still nowhere near the $3.25 figure they provide (without source).

    AM
     
  13. Aug 2, 2007 #12

    LURCH

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    I'm definately missing something here. The mass of the CO2 put out by the vehicles > than the mass of the fuel burned?
     
  14. Aug 2, 2007 #13

    AlephZero

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    Correct.

    The mass breakdown of CO2 is 27% carbon (from the fuel) and 73% oxygen (from the air).
     
  15. Aug 3, 2007 #14

    Andrew Mason

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    As AlephZero has pointed out, this has to do with the chemistry of burning gasoline. Gasoline is a collection of different hydrocarbons, so it is not easy to be precise. If you burned natural gas, CH4 you would produce one mole of CO2 for each mole of methane + 2 moles of water. A mole of methane has a mass of 16 grams and a mole of CO2 is 44 grams, so the CO2 produced weighs 2.75 times as much as the fuel.

    If you use C8H18 for gasoline (octane - mw = 114)
    2 moles of fuel (228 g) react with 25 moles of oxygen to produce 18 moles of water and 16 moles of carbon dioxide (704 g) so the ratio is about 3:1.

    So as it is, my estimate was a bit low. 18000 kg of gasoline would produce about 54,000 kg of CO2.

    AM
     
  16. Aug 10, 2007 #15
    I'd be really skeptical that the batteries last that long

    8 years is a LONG time for those batteries to last. The Ni-MH batteries most common today are rated for about 600 recharges, which may be 8 years but I'd doubt it. The average cell phone uses these or Lithium Ion batteries, and they don't typically last more than 3-4 years. The only real difference is the size of the battery.
     
    Last edited: Aug 10, 2007
  17. Aug 21, 2007 #16
    No, the main difference is that the battery pack is limited to a charge level of between 50% and 80%.

    This is apparently how they are able to achieve such an amazing life.
     
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