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Carbon footprint clarification

Discussion in 'Electric Vehicles' started by kgb, Aug 26, 2010.

  1. kgb

    kgb Member

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    I'm sure it's somewhere here in the forums, but I wasn't able to find it. I wanted clarification about the carbon emissions question.

    The statement that an electric vehicle emits less carbon per mile is backed up by what evidence?

    Specifically, I realize that the coal burning power plant emits a certain amount of carbon for each kwatt produced. And I realize that the EV uses a certain amount of kwatt to move the EV each mile. On the other hand, an ICE has certain tailpipe emissions.

    I would like a start to finish comparison of the cabon footprint for EV vs. ICE.

    Starting with the assumption that we are using existing coal mines and existing oil wells.

    FOR ICE: Carbon emitted...
    extracting and storing the oil,
    shipping the oil by tanker,
    refining the oil to gasoline,
    shipping the gasoline to the gas station, then
    burning it in the ICE

    FOR EV: Carbon emitted...
    extracting the coal,
    shipping the coal,
    burning the coal to make electricity,
    transmitting the electricity via power lines through transformers etc...,
    energy loss via charging the battery, then
    energy used in the electric engine

    Let's start with that, later we can discuss the amount of carbon used in the manufacture and recycling of ICE vs. electric engine & battery.
     
  2. Kevin Sharpe

    Kevin Sharpe Active Member

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    Why? Some of us drive electric because we can use 100% renewable energy...
     
  3. kgb

    kgb Member

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    Worst case scenario. Also, I live in USA where we pay more to have our coal electricity branded as "renewable."
     
  4. felix the cat

    felix the cat P1370 (Europe)

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    This has been discussed before several times. Latest thread see here:

    http://www.teslamotorsclub.com/showthread.php/2625-CO2-Emissions-EV-vs-Diesel?hig

    But many of the comparisons doesn't take into account the energy, which is needed to produce oil, refine it and transport. If you know that more and more of the oil is coming from non conventional sources like deep seawater oil, canadas oil sands the energy invested to produce the oil is increasing steadily, worldwide! Hence things are getting worse and worse for the petrol powered cars, while for the electric car it's getting better and better, as we are scaling up renewable energy sources.

    I'm driving an electric scooter. It "burns" 40wh per km or 60 wh per mile. For the E-scooter driven with electricity from coal this would come down to 40gCO2/km or 60gCO2/mile. which is considerably less than a gaz-scooter (100gCO2/km), taking into account the energy to produce and refine the oil even 130gCO2/km or 195g/mile.

    As the electric drivetrains gets into the mass market, lightweight vehicles with better drag coefficent as the roadster - or my electric scooter - will be developed, the efficiency can even be two times better than now. Those vehicles will also have a better range as a further advantage to conventional electrified vehicles.

    The electric drivetrain is definitely the way to go, as it will induce the development of cars and vehicles with higher efficiency!
     
  5. rolosrevenge

    rolosrevenge Dr. EVS

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    Right behind you...
    The fallacy with comparisons with coal is that there is no utility in North America that is powered 100% by coal. This is because of interconnection and this little thing known as Kirchhoff's Current Law. From this law we learn that because of interconnection, a hydro plant some 500 miles away from your outlet is providing some small fraction of the power that you receive. The same goes for any power plant in the US. Therefore, 100% coal is not only a worst case analysis, but an unattainable worst case analysis. The same also goes for anyone's claim of 100% renewable energy. Unless they are in a stand alone system, not connected to the grid in any way, they are getting some dirty power.
     
  6. Kevin Sharpe

    Kevin Sharpe Active Member

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    I only purchase 100% renewable energy from a company who only sells 100% renewable energy, so I think I can claim to be using 100% renewable's.... I appreciate that the electrons I receive from the grid come from multiple sources (including some that are 'dirty') but if that's your argument then I don't really know what to say...

    Personally, I just wish that users of 'my' grid would stop contaminating it by purchasing 'dirty' electricity :wink:
     
  7. kgb

    kgb Member

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    Although this isn't the direction I wanted this thread to go, I'll bite...

    I find it disappointing, yet slightly humorous, that my electric provider will sell electricity to me at one price if I agree that it is from coal, but they will sell me the same electricity to me at a higher price if I agree that it is from renewable sources. Believe me, I want renewable sources, but it is all the same electricity... so I opt for the less expensive electricity. That is, until I get my solar panels installed!
     
  8. kgb

    kgb Member

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    That thread does not take into consideration the production and distribution of hydrocarbon vs. electricity. I was just wondering if someone actually did the analysis of carbon/mile for each natural resource from the time it is pulled from the earth through the time it pushes a car. If we only look at part of the supply chain, we get a distorted picture. The prime example, if we look at the carbon foot print from tailpipes only, the EV has 0 carbon exhaust.

    Let me be more clear, I could look up all the numbers and do the basic multiplication, but that would take hours. So, does anyone actually know the numbers next to each step...

    FOR ICE: Carbon emitted...
    extracting and storing the oil,
    shipping the oil by tanker,
    refining the oil to gasoline,
    shipping the gasoline to the gas station, then
    burning it in the ICE

    FOR EV: Carbon emitted...
    extracting the coal,
    shipping the coal,
    burning the coal to make electricity,
    transmitting the electricity via power lines through transformers etc...,
    energy loss via charging the battery, then
    energy used in the electric engine

    If you know one chime in... I'll do the multiplication. Thanks.
     
  9. ChadS

    ChadS Petroleum is for sissies

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  10. mt2

    mt2 Member

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    What you are talking about is the old "long tailpipe" argument and it's counterpoint, the "well to wheel" analysis. No need for you to do the math. A Google search for "well to wheel" will give you tons of conflicting research papers. I find this presentation on the GREET model cuts to the chase, http://www.transportation.anl.gov/pdfs/TA/273.pdf. Page three summarizes nicely.

    Note that the presentation was done in 2003 and our dependence on coal has dropped five or six percentage points since then. I don't have exact numbers but 48% coal is often quoted based on the DoE 2008 statistics. It continues to drop as older plants are modernized or taken off line.
     
  11. stopcrazypp

    stopcrazypp Well-Known Member

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    #11 stopcrazypp, Aug 26, 2010
    Last edited: Aug 27, 2010
    Just a note: all the numbers you want will vary based on region and method each of those are done. I'm assuming you want US average.

    burning the coal to make electricity
    Coal Emissions from US generation (2008 most recent available):
    1994993381Mg/1985801247MWh = 1.00463g/Wh = 1.00463kg/kWh = 2.21483lbs/kWh


    transmitting the electricity via power lines through transformers etc

    http://tonto.eia.doe.gov/ask/electricity_faqs.asp#electric_rates2

    energy used in the electric engine
    For the plug to wheel / nozzle to wheel part, I recommend looking at cars that have both ICE and EV versions and also tested under the same cycle. For example, the MINI-E and the RAV4EV (keeping in mind the EPA changed their rating method in 2008).

    The newest EV fueleconomy.gov has numbers for is the 2003 RAV4EV (pre-2008 numbers)
    City: 27 kWh/100mi
    Combined: 30 kWh/100mi
    Hwy: 34 kWh/100mi
    (No combined figure, but calculated one by using the formula here, keeping in mind it is kWh/100mi and not mpg. http://www.epa.gov/fueleconomy/420f04053.htm)
    http://www.fueleconomy.gov/feg/calculatorSelectEngine.jsp?year=2003&make=Toyota&model=RAV4%20EV

    Most efficient gas 2003 RAV4 (2WD 2.0L I4 5 speed Manual) (also pre-2008 numbers)
    City: 25mpg
    Combined: 27 mpg
    Hwy: 31 mpg
    http://www.fueleconomy.gov/feg/calculatorCompareSideBySide.jsp?column=1&id=19115

    http://www.epa.gov/oms/climate/420f05001.htm

    extracting and storing the oil
    97% Petroleum Recovery Efficiency (unclear if storing is included)
    From 2001 GM Global Alternative Propulsion Center (GAPC) study done by ANL.
    http://www.transportation.anl.gov/pdfs/TA/166.pdf

    refining the oil to gasoline

    85.5% Petroleum Refining Efficiency: 340 ppm S Conventional Gasoline
    From 2001 GM Global Alternative Propulsion Center (GAPC) study done by ANL.
    http://www.transportation.anl.gov/pdfs/TA/166.pdf

    83.0% Petroleum refining and distribution efficiency
    Electric and Hybrid Vehicle Research, Development, and Demonstration Program; Petroleum-Equivalent Fuel Economy Calculation (published in year 2000)
    http://www.epa.gov/EPA-IMPACT/2000/June/Day-12/i14446.htm
     
  12. kgb

    kgb Member

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    Thanks, that answers my question.
     
  13. EVNow

    EVNow Active Member

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    One thing to note is that energy used to get a gallon of gasoline has been going up. Checkout the EROI of oil from various wells, for eg. The tar sands are much worse - and we are increasingly getting our oil from Canadian sands. They have betwen 3:1 and 5:1 EROI. I expect that carbon foot print to be much larger than something we get from an old Texas well.

    eroei_chart.jpg
     
  14. stopcrazypp

    stopcrazypp Well-Known Member

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    If that is true then recovery/refining efficiency may be significantly lower now. It would be nice to have some updated data. The data I have on that is a decade old so it may not be accurate anymore.
     
  15. vfx

    vfx Well-Known Member

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  16. Larry Chanin

    Larry Chanin Model S Perf Sig 1055

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    I would think so.

    At 55 mph a Tesla Roadster would draw about 33% less power that the Leaf that was used for this study. Using the numbers quoted in the article and increasing them by 33%, it seems that even in dirty electricity regions that the Roadster would create a smaller carbon footprint than virtually any ICE vehicle. It will be interesting to see the kilowatt-hour per mile data on the Model S when it is available, but I'll bet it is similar to the Roadster.

    Larry
     
  17. vfx

    vfx Well-Known Member

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    I won't believe it until they show me. These studies always seem to start with gasoline magically in the tank of an ICE car. As we all know it took massive amounts of energy to get there. Show me the explorationdrillingpumpingshippingpumpingrefiningpumpingtruckingandpumping!
     
  18. hcsharp

    hcsharp Active Member

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    Just added that word to my spell checker.
     
  19. rabar10

    rabar10 FFE until Model 3

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    Mod note: posts specifically comparing the efficiency of Roadster and Model S went here: Efficiency comparison - Model S v. Roadster
     
  20. rabar10

    rabar10 FFE until Model 3

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    While (as Larry pointed out) that NYT article stated that the study was well-to-wheels (or coal-mine or what-have-you), I don't think its full text will be available until tomorrow:
    Will have to double-check then...
     

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