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Energy wars (don't get excitied)

  1. Nov 28, 2007 #1
    energy wars (don't get excited)

    My friends (4) and I were discussing energy in the context of transport., ...it quickly spun into a full-blown argument with just me defending electricity. Eventually it was a mess as I started talking about the need for a parameter and everybody getting confused.

    Told you it wouldn't be very exciting!

    Anyway, Their argument was that "electric cars" could never beat a car powered by an ICE (internal combustion engine), in either weight,size,dimension/whatever. And mine was almost (ex.: energy density of petrol) the exact opposite.

    When I'm trying to explain something to someone, I ofter run out of time while trying creating scenarios/examples to make my idea clear.

    I would like to get some input on this topic.
    ?:uhh:¿,
    linux kid
     
    Last edited: Nov 28, 2007
  2. jcsd
  3. Nov 28, 2007 #2

    Mk

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    I don't understand how in a fossil fuel economy electric cars are viable. Isn't the electricity still produced, somewhere else?
     
  4. Nov 28, 2007 #3

    russ_watters

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    Yes, electric cars require a non-fossil fuel energy source to be viable. So talk of electric cars is putting the cart before the horse - we need to fix the power grid first.
     
  5. Nov 28, 2007 #4

    Astronuc

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    One's friends are pretty much correct. Electric cars require battery storage, which requires an electrochemical storage system, which usually means some large mass of batteries based on voltage, current and stored energy. Most batteries are metal.

    As Russ indicated, the electricity has to be generated somewhere, whether by coal, oil, natural gas, nuclear, hydro, solar or wind power. Well gasoline has to be refined from crude oil which has to be extracted from the ground, and the US imports most of it's crude oil since domestic sources have been depleted, except for those in the Gulf and the north slope of Alaska, the latter of which would be depleted in about a decade or two.

    Honda is now attempting to perfect a fuel cell car which utilizes hydrogen. Hydrogen storage is the key challenge.
     
  6. Nov 28, 2007 #5

    Office_Shredder

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    Except that to get hydrogen, you use electricity anyway, and the argument is that this is less efficient than just burning gas for the powering of the car in the first place
     
  7. Nov 28, 2007 #6

    Astronuc

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    Hydrogen can be generated in a chemical process, and since oil is being taken from reservoirs, which are more difficult to develop, the energy to extract the crude oil requires much more energy. Crude oil is a finite resource, while hydrogen in water is not. Solar (direct) and hydro and wind (indirect solar) are abundant and essentially endless sources of energy.
     
  8. Nov 28, 2007 #7

    Kurdt

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    What exactly did they mean by that? There are several examples recently of electric cars being a similar size and weight to a normal ICE car. Take for example the Tesla roadster.
     
  9. Nov 28, 2007 #8

    Office_Shredder

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    You can use that renewable stuff to power an electric car just as easily, no?

    Hydrogen can't be generated in a chemical process that doesn't require electricity (see: electrolysis)
     
  10. Nov 28, 2007 #9
    Have you are anyone else seen "Who Killed the Electric Car?" at http://video.google.com/videoplay?d...338&start=0&num=10&so=0&type=search&plindex=2

    Any comments?
     
  11. Nov 28, 2007 #10
    The big point indeed is the incompatibility of slow depletion of liquid fossil fuels and our high mobility demand. And from some inside information about vigorously attempting to squeeze out the last drops of depleted oil fields, there is nothing to be optimistic about.

    Not only thinking of cars but also air traffic. Fossil fuel is a direct energy producer, whereas electricity and hydrogen are merely energy carriers. And as usual the longer the chain of energy conversions the lower the efficiency. Sure, you can convert to electric cars, but it's easy to calculate that the power grids are not nearly adequate to supply for such an increase in demand. And the fossil fuel not used in the car will be used in the power plant. No gain.

    Enough wind? A single turbines typically generate about 1-2 megawatt for 20% of the time. cars when cruising may use about 30-40 horsepower, just ball park figures. That's about 25kw. So assuming 50% efficiency one wind turbine can support 20-40 cars for 20% of the time. So we'd need one wind turbine for every one to two cars. But what if there is no wind during rush hour? And how are we going to propel all those air liners?

    It's clear that the energy demand is way over what alternatives can offer, so we'd better start building nuclear plants right now, while reducing our own fuel requirements. that's why I selected a car that is doing 57 miles to one gallon diesel or was it purely for economical reasons?
     
  12. Nov 28, 2007 #11

    Kurdt

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    Electric cars are more efficient than combustion engine cars. It is far more efficient to use fossil fuels to generate electricity than to use them in a combustion engine. Using my previous example of the Tesla roadster, it has an effective efficiency of 135 miles per US gallon. Russ has pointed out however that electricity generation issues will have to be resolved.
     
  13. Nov 28, 2007 #12

    Astronuc

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    Yes.

    Thermochemical hydrogen produced from a vanadium decomposition cycle
    http://www.freepatentsonline.com/20050013771.html

    Other thermo-chemical processes are the sulfur-iodide process and calcium-bromide process. One certainly needs electricity to run motors etc, and even oil refineries use electricity, but one does not need electrolysis to extract hydrogen from water. On the other hand, chemical reactions are essentially electro-chemical.

    See - 2.1 Sulfur-Iodine Cycle (S-I) - in:
    http://www.inl.gov/technicalpublications/Documents/3396561.pdf
     
    Last edited: Nov 28, 2007
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