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CO2 Emissions: EV vs Diesel

Discussion in 'Energy, Environment, and Policy' started by PeterW, Apr 19, 2009.

  1. PeterW

    PeterW Member

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  2. Cobos

    Cobos S60 owner since 2013

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    Very easy. Shoddy science. The whole article balances on a single fact sheet at Transport Watch UK where they claim the well-to-wheel efficiency in the UK is 24%. They fail to list any sources for those numbers and since the entire comparison is using those numbers it all falls down like a house of cards.
    Take a look here for a more accountable dataset.

    Cobos
     
  3. vfx

    vfx Well-Known Member

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  4. stopcrazypp

    stopcrazypp Well-Known Member

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    #4 stopcrazypp, Apr 19, 2009
    Last edited: Apr 19, 2009
    First of all they have taken the totally wrong approach to determining carbon emissions. To do that you do NOT take efficiency number and directly compare if you want accurate rather than ball-park results. You actually figure out the carbon emissions per mile directly, because even if two sources have the same efficiency they may have varying amounts of emissions. That means taking the actual mpg numbers from a Diesel and figuring out CO2/mile (as they have been doing for emissions for quite some time) and then taking the Wh/mile number for the EV (has to be a comparible vehicle) and figuring out the CO2/mile, accounting for any losses.

    Already one big flaw the reporter made is using the 45% number for diesel which DOESN'T include any drivetrain or refining losses on the diesel to compare with the 24% number for the EV which does (if they want to play that game we have 80-90+% for electric motors not including any other losses). Also the scenario where EVs are 2x worst is in the scenario of 100% coal (very very rare) according to their model. On the UK mix, the EVs are only 10% worst than diesels according to their methods.

    And another thing, if the UK has the goal of decreasing their CO2 emissions, cleaning up the grid is a NECESSITY; this goes for any country. That means EVs benefits from this goal.

    GM-Volt picked it up also. Some good comments there by some knowledgeable people. (Though there are some anti-EV people taking this study as fact).
    http://gm-volt.com/2009/04/19/study-calls-environmental-benefits-of-electric-cars-fiction/
     
  5. stopcrazypp

    stopcrazypp Well-Known Member

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    #5 stopcrazypp, Apr 19, 2009
    Last edited: Apr 19, 2009
    Okay just to put this thing to bed, I did calculations on the MINI E vs the MINI Diesel (doesn't get more direct than this) before here: http://www.teslamotorsclub.com/21585-post8.html

    I'll summarize results:
    (Original calculations: Electricity transport, Petro refining/transport efficiency not factored)

    Mini E (167km combined range & 28kWh usage + 80% charging loss = 35kWh plug to wheel usage = 0.21kWh/km):
    CA Power (724lbs/MWh = 328grams/kWh) = 68.9 gramsCO2/km
    US Avg (1329lbs/MWh = 603grams/kWh) = 126.6 grams/km
    UK Avg (from their data = 687.5gms/kWh)=144.3 grams/km
    Coal__ (2249lbs/MWh = 1020grams/kWh) = 214.1 grams/km

    Mini Diesel:
    Manual = 104 grams/km
    Auto__ = 134 grams/km

    Mini Gas:
    Manual = 129 grams/km (from mini.com but no direct link)
    Auto__ = 142 grams/km (figured using 32mpg manual, 29mpg auto)

    (Figuring Electricty Transport Efficiency = 92.4%, Petroleum refining/transport = 83%, Diesel may take more refining but giving it benefit of doubt that it isn't much more)

    Mini E:
    CA____ = 74.6 gramsCO2/km
    US Avg = 137.0 grams/km
    UK Avg = 156.2 grams/km
    Coal__ = 231.8 grams/km

    Mini Diesel:
    Manual = 125.3 grams/km
    Auto__ = 161.4 grams/km

    Mini Gas:
    Manual = 155.4 grams/km
    Auto__ = 171.1 grams/km

    How clean is the electricity I use? - Power Profiler | Clean Energy | US EPA
    http://www.miniusa.com/minie-usa/pdf/MINI-E-spec-sheet.pdf
    http://www.mini.com/com/en/ecom_rfi/_download/MINI_Cooper_D_September2007.pdf
    Electric and Hybrid Vehicle Research, Development, and Demonstration Program; Petroleum-Equivalent Fuel Economy Calculation | Federal Register Environmental Documents | USEPA
    http://www.epa.gov/cleanrgy/energy-and-you/affect/coal.html

    Keep in mind I am assuming 80% charging losses, which is the worst case they assumed.

    The relevant numbers are the UK & US numbers vs Diesel after factoring in electricity/fuel transport/refining losses. The EV still comes ahead over the automatic mini diesel while being worst than the manual version. Given no shifting is involved in the EV, the comparison with the auto seems to make sense. They are right that 100% coal is pretty bad, it's worst than the gasoline version & diesel, but 43.6% worst than the diesel factoring in petroleum losses, not 2x worst.

    Where they got worst numbers is they were optimistic about Petroleum refining/transport losses (assumed 89% rather than 83% since they went from 45% efficiency of diesel to 40% after refining) & their number for coal emissions (1,380 gms/kWh) is worst than the US avg (2249lbs/MWh or 1020grams/kWh). This is a big flaw: They also assumed drivetrain losses for diesels and EVs are the same (not true). So basically they twisted some numbers, (optimistic about diesel, pessimistic about EVs) to get the worst results for EVs.

    Sorry for the extremely long post.
     
  6. dpeilow

    dpeilow Moderator

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    #6 dpeilow, Apr 20, 2009
    Last edited: Apr 20, 2009
    Transport Watch claims to be independent but the reality is they come out with a lot of pro-road (and that is ICE road), pro-air material like this. An investigation of some of their other "fact sheets" shows that a lot of their starting assumptions are designed to get results like this.

    Also note that the Telegraph is probably the most right of the right wing press. They also had been fairly supportive up until now, but have decided to jump on the same bandwagon as the Times and Mail in bashing government policy.

    It's almost as if they were happy to humour Tesla et al with column inches as long as they were not seen as a big threat, but that has now changed.


    By the way, this and this page on the website would seem to indicate he is a one man band with possible funding from a large road haulage company. I remember now, I've come across him before - he is also known as a bit of a nutjob who advocates ripping up railways and replacing them with guided-busways or multi-lane highways (how many lanes can you get on a typical railway anyway?) He seems to submit a lot of "evidence" to government committees etc, and unfortunately seems to have influenced the thinking of at least one conservative MP. It's pretty pathetic that the Telegraph feels the need to base their case on a source like that. Interestingly this will be good test of Boris Johnson's commitment to the electric car cause, if indeed his old employers and his current national party are going to take this stance (note Conservative central office has been quiet on this so far, it would appear, but it is interesting that many of their supporters in the press are publishing stuff like this).
     
  7. vfx

    vfx Well-Known Member

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    So he's like GM and the tire companies gutting the US of all electric trains to replace them with buses.
     
  8. vfx

    vfx Well-Known Member

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  9. JRP3

    JRP3 Hyperactive Member

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    I think Kent has been pro hybrid, (Volt), but anti EV, for a while, if that makes any sense. I think he's pro GM more than anything.
     
  10. graham

    graham Active Member

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    I wonder if he will become pro EV if GM decides to release a true BEV?
     
  11. vfx

    vfx Well-Known Member

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    #11 vfx, Apr 21, 2009
    Last edited: Apr 21, 2009
    Good question!

    At that point we will learn if he is a passionate disbeliever or a paid shill.
     
  12. JRP3

    JRP3 Hyperactive Member

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    For all the time and effort he puts in I hope he's getting paid.
     

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