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why don't we just use the 7.5kWh directly in an EV?

Discussion in 'Energy, Environment, and Policy' started by montgom626, Mar 25, 2013.

  1. montgom626

    montgom626 Active Member

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    How much energy does it take to produce a gallon of gasoline? - Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com


    If it takes 7.5kWh of electricity (plus some natural gas, too) to refine one gallon of gasoline from petroleum -- then why don't we just use the 7.5kWh directly in an EV?

    7.5kWh of electricity could move and EV anywhere from 30 to 60 miles or so.

    If you put the gasoline in a car that get the national average of 25mpg, you only go 25 miles -- and you should also count the 7.5kWh against that, too. Which lowers the MPGe of the ICE car even further; and it raises the carbon emission to levels far higher than the EV, obviously.

    And that is only the energy it took to refine the petroleum -- in reality, you should also count all the other energy inputs to produce the gasoline!

    So, an EV is going to be much, much more efficient than a ICE. And using a lot of EV's will likely reduce the overall load on the electrical grid.

    So, an EV is going to be much, much more efficient than a ICE. And using a lot of EV's will likely reduce the overall load on the electrical grid.
     
  2. Zythryn

    Zythryn MS 70D, MX 90D

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    This is pretty well debunked and a worst case scenario. Kind of like claiming EVs don't work because once a decade you need to drive cross country.
    It does not help EV acceptance to take such an inflated, misleading number. It is a good point, as electrical power is used in refineries, just not that much.
     
  3. AMPd

    AMPd Active Member

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    We should, and hopefully one day we will
    Long range EVs are quite new, not many people have heard of tesla so they're still stuck in the old ice mobile
    many who have heard of tesla have range anxiety when going on long trips, which should be fixed when superchargers are built out
     
  4. montgom626

    montgom626 Active Member

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    So 3kW??? What is the real number?
     
  5. Zythryn

    Zythryn MS 70D, MX 90D

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    All depends what you include. If you simply divide the electricity used by refineries in the US by the gallons produced you get about .2 kWh/gallon.

    I believe there is a thread on this already, I'll see if I can find it, here is one at the Leaf site though... My Nissan Leaf Forum View topic - 7.5 kWh of electricity to produce a gallon of gasoline?

    Basically, all I am saying is be careful with your sources. Making way out of left field, easily falsifiable comments just hurts the cause. EVs don't need false arguments backed up with bad data.
     
  6. montgom626

    montgom626 Active Member

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    .2 kw per gallon? Then the argument that I posted is meaningless. Too bad.
     
  7. dhrivnak

    dhrivnak Active Member

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    The problem is most refiners use part of the feedstock (oil) or the left over sludge (PET coke) to produce a lot of the power to run the refinery. So with all the co-generation of power it is not a clean break as few if any refineries would purchase all power needed as electricity from the grid.

    While our company does not refine oil we have have three separate power plants that produce most of our electricity and a lot of steam used in processing. So if you look at say something like our KWh/kg of product you get one very small number if you take the KWh we purchase. A noticably higher number if you look at total KWh we both by and produce and a MUCH higher number if you convert all the steam used for process heating, into a KWh basis. Which is the right number?
     
  8. richkae

    richkae VIN587

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    I analyzed this question a couple of years ago: Refining | High Speed Charging

    The summary: the electricity used by the refineries is about 5% of the energy used. But if you used the raw energy sources that the refineries consume to refine gasoline instead to produce electricity it would provide electricity to drive at least 1500 million EV miles - which is about half the passenger miles driven in the US per year.
     
  9. wycolo

    wycolo Active Member

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    > All depends what you include. If you simply divide the electricity used by refineries [Zythryn]

    Why limit this to just the refineries? ALL energy used to create that marginal gallon of gasoline/diesel vs your KWHs at home. An energy to energy comparison.
    --
     
  10. richkae

    richkae VIN587

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    I did the calculations entirely on the refining question because you can get good data from the EIA website on the energy consumed by the refineries.

    I could not easily find good data on the transportation losses: trucking gasoline from the refinery to the gas station, and transporting crude to the refinery.

    Nor could I find good data on the extraction. The energy for extraction is incredibly varied depending on how it is extracted.
    I looked at pump jacks: Day in the Life of a Pump Jack | High Speed Charging but pump jacks are only a portion of oil extraction.
    I know that the Canadian tar sands which produce a lot of oil for the US use a massive amount of energy to turn tar sand into crude oil, but I'm not sure how much.
     
  11. damianku

    damianku Member

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    You are comparing apples to oranges. Gasoline is a concentrated PORTABLE energy source. Electricity not so much.

    As stated above a lot of refineries use their own produced energy. Of the ones I have worked in most do not consider electricity a significant cost. Some do not even track electricity usage at all it is such a minor expense.
    $100/barrel of oil. That is a significant expense.
     
  12. SuperCoug

    SuperCoug Model S Res #7734

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    I sure as heck can't drive 60 miles on 7.5 kWh in my Model S.
     
  13. richkae

    richkae VIN587

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    A Model S is a massive luxury performance EV. More efficient EVs can go 45 miles on 7.5 kWh, but 60 is a pretty huge stretch.
     
  14. stopcrazypp

    stopcrazypp Well-Known Member

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    #14 stopcrazypp, Mar 26, 2013
    Last edited: Mar 26, 2013
    We've discussed this thoroughly already once before:
    http://www.teslamotorsclub.com/showthread.php/475-How-much-electricity-to-produce-gasoline

    And I've done the math once before already but here's the key points:
    1) 7.5kWh per gallon is the ENERGY required to refine gasoline, NOT the electricity (big difference).
    2) 0.31kWh of purchased electricity per gallon based on 2006 data.
    3) ~1kWh of electricity can be made from the natural gas, steam, and coal feedstocks needed to refine a gallon of gas. There's some still gas and LPG I didn't convert though.
    4) ~2.3-3kWh/gallon of electricity can be made from all feedstocks if you assume 30-40% conversion efficiency for the 7.5kWh of energy.
    http://www.teslamotorsclub.com/showthread.php/475-How-much-electricity-to-produce-gasoline/page11?p=90733&viewfull=1#post90733

    In short, using the EPA 38kWh/100mi rating of the Model S, you can drive 6-8 miles if you took all the feedstocks needed to refine a gallon of gasoline and used it to make electricity. You can drive only 0.8 mile if you took only the purchased electricity.
     
  15. GSP

    GSP Member

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    7.5 kWh from my electric utility will drive my Chevy Volt about 22 miles. It is a compact C-class automobile with good aero and low rolling resistance tires. You might get 30 miles at the most with a minimal A-class BEV, like an iMiEV or Chevy Spark.

    GSP
     
  16. SuperCoug

    SuperCoug Model S Res #7734

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    Then obviously we're energy hogs for driving the Model S. We should be required (perhaps by law) to drive one of these more efficient EVs you reference. In fact, how far can a golf cart go on 7.5 kWh? After all, do we really NEED to travel at highway speeds? :wink:
     
  17. montgom626

    montgom626 Active Member

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    My MS can go about 3 miles (if I drive very carefully, on flat ground 60-65 mph). I know my 2102 Volt can do 38 miles in ideal conditions (ideal is 70 degrees, flat ground, no wind, etc.)

    Now, any EV can really do great at 30-40 mph on a nice country road. This is also true for an ICE. I can really max out miles per kW. A bit artificial, but easy to do.
     
  18. brianman

    brianman Burrito Founder

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    You sound like a politician. I'll hold off on saying more so the mods don't have to set fire to my computer.
     
  19. Robert.Boston

    Robert.Boston Model S VIN P01536

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    #19 Robert.Boston, Mar 27, 2013
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    To the contrary, we need to travel at ludicrous speed!
     

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