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China pushes Coal-powered EVs despite Dirtier air quality

Discussion in 'Prius, Hybrid, EV and Alt-Fuel News' started by Troy Heagy, Aug 28, 2014.

  1. SageBrush

    SageBrush Senior Member

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    3 miles/kWh sounds like a reasonable estimate for fair weather driving but not a year round average in 4 season climates.

    As for the 40 - 45% coal, what are you presuming the remainder is ? Say 22.5% clean and 35% NG. If you assume that NG is about equivalent to Prius you can parametrize an easy calculation:

    Emissions:
    Prius per mile = x
    NG per mile = x
    Coal per mile = 2x
    Clean per mile = 0

    100 miles in a Prius = 100x
    EV = 95x + 22.5x*0 + 35x = 130x

    So using your grid, an EV is 30% dirtier than a Prius given equivalent heat efficiencies*

    * (which of course they are not.) Prius is about 0.36*0.82 -- oil to wheels
    EV is about 0.33*0.93*0.85*0.85 -- coal to wheels
     
    #21 SageBrush, Sep 4, 2014
    Last edited: Sep 4, 2014
  2. wjtracy

    wjtracy Senior Member

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    These days the EPA database gives the CO2/mile for the cars based on their fuel mix data. It struck me that the numbers quoted by the OP from the old article were probably slightly optimistic compared to what we cite these days based on the EPA/Greet (sp?) data base, also for example there was the MotorTrend article that gave the maps of where EV were better etc. So I sort of gave up making up my own fuel mix. But something like 25% natgas at half the carbon of coal and 25% nuke at zero carbon.
     
  3. Zythryn

    Zythryn Senior Member

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    Sage, you are basing your opinion on incorrect information.
    The EPA does use an adjustment for winter conditions. It may be more severe for some, and milder for others.
    3miles/kWh is a good year round average for energy used by the car in the case of Tesla's and from the wall for most other EVs.

    In our 85kWh we are averaging 339 Wh/mile (just a sliver under 3miles/kWh) and 290 Wh/mile in our 60kWh over 17,000 miles (2 and 1 winters respectively).
    The Leaf, Miev, i3, etc are more efficient than the 60kWh Model 3.

    So I would say 3miles/kWh is a good, conservative average of energy used at the wall.
     
  4. Troy Heagy

    Troy Heagy Member

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    Greenercars.org agrees with you & they have the calculations to back it up. They also take into account actual lung-destroying pollution (CO, HC, NOx, PM).

    Surprisingly they also rated the Tesla and Rav4 EV as less clean than a Jetta Wagon (diesel). That negates the "EVs are green" perspective often pushed by the electric bible thumpers. They are really not any different than the California-qualified diesels and gasoline-hybrid cars we have now. ;) :) :D
     
  5. hill

    hill High Fiber Member

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    Sounds like diesel urban legend promotions
    ;)
    Yea, what the, 'dirty-EV' camp deliberately forgets to mention is the high ratio of owners that primarily charge on their home's rooftop PV. And of course, the Tesla owners taking advantage of the super charger network are primarily running renewable juice. But of course that's no where near as titalating as the dirty EV spin.
    .
     
  6. austingreen

    austingreen Senior Member

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    In 2010, the last full figures the eia has, we get about 2.3x ghg equivelent per gallon equivalent of electricity versus gasoline. Accourding to other figures the average new car gets 25 mpg, average plug-in on electricity around 100 mpg. If we use averages for the electricity mix and the new car mix, a plug-in while in charge depletion mode will generate about 40% less ghg. Of course people with the coal argument want to believe the guy that buys a tesla really drives in indiana, and would have bought a prius. OK, over 40% of new plug-ins are being sold in california. That 89 mpge tesla S 85 kwh will generate about 90 g CO2/miles (current pg&e mix) versus a prius which generates 218 g/mile, or a Lexus GS hybrid 351/mile. Many choose wind and solar to power their plug-ins, making them cleaner than even PG&E electricity.

    Even california is getting less carbon intense, but there are better reasons than carbon footprint for china, with a much dirtier grid to support plug-ins. The president is going to speak tonight of a renewed war in Iraq and Syria against the islamic state. China can't afford to be as adicted to oil as the US has become.

    No one plugs into the average grid. The majority of americans that buy plug-ins have much cleaner than average electricity. The chinese have much dirtier electricity, but they can clean it up, much easier than trying to import as much oil as sticking with gasoline would do. Consumer reports estimates seem way off on many cars. In the case of the volt we have on star which actually measures electricity and gas consumption over years of real owners. On star figures for the volt are much better than CR.
     
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  7. SageBrush

    SageBrush Senior Member

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    Fair enough, and to clarify the calculation:
    • Over 100 miles the 'average new car' uses 4x CO2 equivalents while the EV consumes 2.3x CO2 equivalents. 2.3/4.0 is a bit less than 60%.
    Now let's check Prius:
    • At 50 mpg and the same 100 mile trip, the Prius consumes 2.0x ghg equivalents and the EV the same 2.3x. The Prius generated 2/2.3 = 87% the ghg of the EV.
    These calculations are based on US average grid. AG does not like them, and I agree. The reality is actually considerably worse for the EV side because marginal emissions should be considered, not averages. If the marginal emission is 50% NG and 50% coal then the relative ghg equivalent is about 25% higher, or 2.9. Now the Prius CO2 emission profile = 2/2.9 = 69% of the EV. And remember, that is before we consider opportunity cost.

    I am very sympathetic to the foreign affairs angle; in fact, I consider it the single best reason to not be anti-EV. But even starting and ending on the topic of foreign oil, a switch to Prius and much less expensive overall conservation will cut oil use easily by 50%. That alone will destroy the profit machine of OPEC et al. Add 5-10 Kwh to hybrids, and watch the oil consumption drop another 25%. THAT is the rational, efficient, and practical way to deal with radical countries and crazy religions.
     
  8. GrumpyCabbie

    GrumpyCabbie Senior Member

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    Well my small electric company who only have 130k customers have set up a network of free electric car charge points around the UK. They've celebrated their first million miles of electric charging from their network. Not bad considering the small number of electric vehicles in the UK and the small size of the company.

    Electric Highway delivers 1 million miles of free travel - News - Ecotricity

    The reason I added this to this thread is that these million miles were free to the driver but that they are also all powered by wind or solar renewable energy. Perhaps that helps counter the dirty coal powered BEVs from China?
     
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  9. SageBrush

    SageBrush Senior Member

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    Here is another calculation courtesy of the EIA that is I think easier to use:
    Calculations and References | Clean Energy | US EPA

    A kWh of electricity at the plant emits 0.69 kg of CO2
    Transmission costs ~ 8%
    Wall to car motor, another ~14%
    So a kWh of energy at the motor is 0.69/(0.92*0.86) = 0.872 Kg CO2

    Starting from 3 miles per kWh, an EV mile emits 0.872/3 = 0.29 Kg CO2 = 0.638 Lbs of CO2
    50 miles emits 0.638*50 = 31.9 lbs of CO2

    A prius combusts one gallon of petrol to travel 50 miles, equal to 1/0.82 = 1.22 gallons of oil.
    Starting from 20 lbs CO2 per gallon, the Prius 50 miles emits 20*1.22 = 24.4 lbs of CO2

    All told, the Prius emits 24.4/31.9 = ~ 76.5% of the CO2 of an EV that runs at 3 miles per kWh.
     
    #29 SageBrush, Sep 10, 2014
    Last edited: Sep 10, 2014
  10. wjtracy

    wjtracy Senior Member

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  11. SageBrush

    SageBrush Senior Member

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    No doubt, use of MPG(e) would be flawed.

    The only other detail I read that gave me pause was their use of an average MPG for different versions of the same model. This gives non-representative over-weight to the 'eco' and MT versions.
     
  12. hill

    hill High Fiber Member

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    what happened to factoring in the C02 created during drilling - pumping - shipping - refining - delivery etc per gallon ... or does all that get a magic free pass

    [​IMG]

    Nothin' like flaring gas to put on a nice benzine laden light show at night
    Lest we forget - those are the btu's that run both electric generators AS WELL as the refineries ... only after the refinery - you get to either have electricity ... or make more CO2 -burning it in the ICE.
    .
     
    #32 hill, Sep 10, 2014
    Last edited: Sep 10, 2014
  13. SageBrush

    SageBrush Senior Member

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    I'll repost for you with bolding

    A prius combusts one gallon of petrol to travel 50 miles, equal to 1/0.82 = 1.22 gallons of oil.
    Starting from 20 lbs CO2 per gallon, the Prius 50 miles emits 20*1.22 = 24.4 lbs of CO2
     
  14. hill

    hill High Fiber Member

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    Ah ... got it

    .
     
  15. SageBrush

    SageBrush Senior Member

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    I decided to double check the 20 lbs/gallon_petrol and found this from the EIA:
    Since the EPA numbers are based on E0, 20 lbs CO2/gallon is an over-estimate of ~ 1.8%
     
  16. Chazz8

    Chazz8 Gadget Lover

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    China's electric grid is cleaning up as per July 23, 2014 routers article; Beijing shuts big coal-fired power plant to ease smog: Xinhua| Reuters

    Quote from article;
    "(Reuters) - Beijing has closed the first of four large coal-fired power plants set to be de-commissioned as part of the city's efforts to cut air pollution, official news agency Xinhua reported on Wednesday, citing the local planning agency.
    (Snip)
    In the face of growing public anger about persistent smog in the Chinese capital, the government has been under intense pressure to cut coal use and relocate industry.
    Beijing's three remaining coal-fired power plants are all to be closed by the end of 2016."

    Let's see if china can follow through if they start plugging in more EV vehicles.
     
  17. SageBrush

    SageBrush Senior Member

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    That article says that by 2017 local Beijing coal consumption will drop by ~ 45%. Excellent start, but still horrible air pollution in 2017.
     
  18. austingreen

    austingreen Senior Member

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    The plug-in cars because they are such a small percentage of sales shouldn't change the number much, but I am sure they use mpge ;-) One thing is there is quite a bit of seasonality to monthly figures. I was using 2013 and rounding up to 25. I wouldn't put stock in any one month as percentage of cars vs trucks etc can change just based on the gas price, but maybe we will gain an entire mpg like last year.
    New-Car Average Fuel Economy Rose To 24.8 MPG In 2013

    A key difference is older cars end up getting worse mpg, they don't go up with cafe, while plug-ins get cleaner over time. The figures I was quoting were for 2010, but electrical generation has gotten much cleaner since then. Just think in california 39% of people that buy a plug-in also put up solar panels to provide power. China won't be like that, but again who cares.

    Oil is the most scarce energy resource unless you count whale oil
    Oil revenue supports terrorists and causes wars.
    diesel and gasoline ice vehicles have tailpipe pollution that can not be moved outside of China's cities. Electric generation can be cleaned up.
     
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  19. Troy Heagy

    Troy Heagy Member

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    No the Environmentalists that run greenercars.org hate diesels. However they are wise enough to be unbiased in their calculations..... Tesla Model S scored 37% clean and Jetta Wagon diesel scored 38% clean.

    So a "high ratio" of EV owners use solar? What ratio would that be? One-half percent? I have met a FEW owners with solar roofs, but all the solar electricity is used to power the house (not the car). So in reality they are still using grid-powered cars. That leaves almost zero electric drivers that are genuinely using clean solar energy.
     
  20. SageBrush

    SageBrush Senior Member

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    Amusing, you have fallen to the same fallacy as so many EV advocates.

    It simply does not matter *where* the PV is consumed, all that matters is that it is present and off-setting fossil fuel use.
    The trick question regarding a home PV setup is WHY the person invested in PV. If, e.g., they did it to save money on the utility bill unrelated to any other action, then owning or not owning an EV is irrelevant. OTOH, if the EV purchase directly led to purchase of PV then it is reasonable to say that the EV is PV powered.

    An example: I invested in 5 kWh a year of PV a year or so ago. The production is way in excess of my home electricity consumption, and I did not buy the PV with an EV in mind. The excess is off-setting someone else's use that would otherwise be fossil-fuel sourced. If I now buy an EV no additional benefit will accrue to the environment or the grid. You can say that my PV purchase is fueling an EV somewhere but that is nonsense: it is fueling a minuscule portion of any electric appliance that uses grid power. Just as another electric blender is extra load on the grid, so is another EV.
     
    #40 SageBrush, Sep 11, 2014
    Last edited: Sep 11, 2014