Prius PHEV conversion now $4,995

Discussion in 'Prius, Hybrid, EV and Alt-Fuel News' started by clett, Jul 29, 2008.

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  1. Flying White Dutchman

    Flying White Dutchman Senior Member

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    maybe some modern coal gassing plants need to be build? or are there already coal gassing stations in the us?
    this burns more of the coal more efficiently
     
    #21 Flying White Dutchman, Aug 6, 2008
  2. clett

    clett New Member

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    Even when an electric vehicle is running off the worst possible source of electricity (coal), it emits less CO2 overall into the atmosphere than an equivalent gasoline / diesel or hybrid vehicle.
     
    #22 clett, Aug 6, 2008
  3. joewein

    joewein Driving in Japan

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    Yes, coal gasification would be somewhat cleaner, but not many existing coal-burning stations are going to be replaced with anything cleaner during the projected 2 year lifetime of this battery system.

    Plug-in electric vehicles would be genuine "zero emission" vehicles only if you were to live in a country that uses neither coal, oil nor gas for generating power. If you happened to live in Iceland, where 80% of electricity is hydroelectric you would come close. Most other places would not.

    Another point worth considering is that replacing the standard 68 kg NiMH (no lithium ion as claimed in the article) traction battery of your Prius with a 163 kg lead acid one adds an extra 95 kg (210 lb) to the weight of the car.

    An old rule of thumb amongst engineers is that every 100 kg of extra vehicle weight increases fuel consumption by about 1 L per 100 km in urban driving. That means, if you were getting 5 l / 100 km (47 mpg) with the 68 kg battery you'll now only get 6 l / 100 km (39 mpg) with the 163 kg battery on board.

    If you were doing 15,000 km (9000 miles) per year then over the two year lifetime of the battery that would add up to an extra 300 litres (80 gal US) of fuel or its equivalent in electricity = coal, simply because of vehicle weight.

    I think it makes more sense to wait until at least lithium ion batteries become available with enough lifetime for a car. With their higher energy density (four times that of lead acid batteries by weight) you would at least not burn as much coal to carry around batteries.
     
    #23 joewein, Aug 6, 2008
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  4. joewein

    joewein Driving in Japan

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    My sources indicate that it's not the case.

    By comparison, the 1NZ-FXE 1.5 litre engine of the Toyoto Prius manages 34% efficiency when producing 13.5 hp.

    If you consider that charging a lead acid battery is no more than about 85% efficient and that there are transmission losses in the grid between the power station and your home, the coal fired power station would have a hard time delivering power more efficiently to your driving wheels than the Atkinson cycle engine of your Prius.

    Another way to do the math is this: Coal fired power stations in the US produce on average about 2 lbs (0.9 kg) of CO2 per kWh generated. To recharge the 5 kWh pack would therefore generate 4.5 kg (4,500 g) of CO2. The Prius is officially rated at 104 g of CO2 per km. In other words, if you were to drive a Prius for 43 km (27 miles) it would produce as much CO2 as recharging the lead acid battery pack from coal power. The quoted all electric range of a Prius with that specific battery pack is only 10-15 miles (16-24 km). That's without even looking at charging losses, in reality it looks even more bleak for the coal fired battery scenario.

    If you have data that backs your claim, I'd like to see it.
     
    #24 joewein, Aug 6, 2008
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  5. clett

    clett New Member

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    This is correct, which means a car that manages 5 miles per kWh (which is about what a Prius sized EV or PHEV manages in real life) and uses a lithium-ion battery (which are 95-98% efficient) will release about 184 g CO2 per mile travelled, or about 115 g CO2 per km.

    The reason most people assume that a Prius emits less than this (at 104 g/km) is because it is not widely advertised that the published CO2 emissions for gasoline vehicles account for ONLY the CO2 released directly from the vehicle's tailpipe.

    No allowance is made at all for the amount of CO2 (and energy use of other forms) required to get the gasoline from the ground into the tank in the published figures. When you include the drilling, pumping, refining, and transportation of the fuel on a well-to-wheels basis, it adds about 20% extra on top of that, taking it to around 125 g/km.

    However remember that, even in America, coal amounts for only 50% of the electricity grid mix, and the remainder is much less carbon intensive (nuclear, gas, hydro, wind).
     
    #25 clett, Aug 6, 2008
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  6. joewein

    joewein Driving in Japan

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    However Plug-In Supply Inc, the makers of that $4,995 conversion kit, only claim 2-3 miles per kWh (10-15 miles all electric for a 5 kWh battery pack) for their kit in a Prius and I wouldn't suspect them of being overly conservative if they're trying to find buyers.
     
    #26 joewein, Aug 6, 2008
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  7. clett

    clett New Member

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    Plug-in supply, and several others that use lead-acid batteries, only use around 60% of the available capacity of the battery (ie from 20% charge to 80% charge), as full discharges would otherwise ruin the battery within around 200 cycles.

    Their battery is rated at 5 kWh total capacity, but only around 3 kWh is actually used.
     
    #27 clett, Aug 7, 2008
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  8. ken1784

    ken1784 SuperMID designer

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    I think you forgot about transportation of the coal between coal mine to power plant, then it's apprx 10%. Also, there are some power loss between power plant to consumption point, then it's approx 5%.
    Therefore, the number is 115 * 1.1 * 1.05 = 133 g CO2 per km.
    Toyota uses the well-to-tank efficiency is 88%(12% loss).
    TOYOTA: Company > Technology
    Using that number, Prius number is 104 * 1.12 = 116 g CO2 per km.

    Ken@Japan
     
    #28 ken1784, Aug 10, 2008
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  9. clett

    clett New Member

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    Coal power plants are usually close to the coal resources, so little energy is used to transport it to the plant. Neither is the coal refined before burning, so I very much doubt the LCA for coal to power plant would add up to anything like as much as 10%.

    As for gasoline, I have seen a wide variety of figures for well to wheels efficiency. Toyota's figures are very much on the high (optimistic) side. Closer to the average is probably the US Department of Energy figure they typically use for petroleum refining and distribution efficiency (Tp) of 0.830 (83%).

    That would put the Prius at 104/0.83 = 125 g CO2 per km.

    The average amount of CO2 released by USA power stations is 610 g CO2 per kWh, putting an EV today at 90 g/km including your factors. In future it will be much less than this with the shift to renewables and nuclear.
     
    #29 clett, Aug 11, 2008
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  10. Brennos

    Brennos Junior Member

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    how are they pulling off that simulation??
     
    #30 Brennos, Aug 25, 2008
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  11. Theodore

    Theodore Junior Member

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    Dear Sir!
    I would like to ask you....does anyone do the plug in conversion in Europe???? I was looking for it...when I bought my prius...in January...but NOONE !!!!




     
    #31 Theodore, Nov 15, 2009
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  12. hill

    hill High Fiber Member

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    maybe true in a little country like Scotland or the UK, but in the U.S. they can travel hundreds of miles:

    [​IMG]

    then consider the U.S.'s gluttonous usage ... 1,300 coal trains a year, and TWO THOUSAND MILES of coal cars:

    A Reporter at Large: Coal Train-II : The New Yorker

    No one hogs power like us. . . . Burp.
     
    #32 hill, Nov 16, 2009
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