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Technology in Mirai

Discussion in 'Fuel Cell Vehicles' started by usbseawolf2000, May 5, 2015.

  1. usbseawolf2000

    usbseawolf2000 HSD PhD

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  2. bisco

    bisco cookie crumbler

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    looks complicated.
     
  3. usbseawolf2000

    usbseawolf2000 HSD PhD

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    No moving parts but written in foreign (hydrogen) language. :)
     
  4. bisco

    bisco cookie crumbler

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    i suppose time will tell, if we ever get that far. i'm sure fcv's have already logged a ton of miles though.
     
  5. Sergiospl

    Sergiospl Senior Member

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  6. hill

    hill High Fiber Member

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    Sergiospl - I note the frame stopped right here, but I don't know if that's the way Toyota built the video to advertise, or whether it's something else. But the 2:48 mark was where I had to say, "WOOOaaah".

    PApower.jpg

    The message is, "you can distill hydrogen with renewable power!". Toyota fails to mention that same electricity that'd get a hydrogen car 200 miles would get a BEV between 700 miles & 800 miles. And that's why hydrogen is distilled from non-renewable's, instead of electricity. ok, it's NOT quite as dishonest as Phillip Morris used to be;

    [​IMG]

    .... that is ... if you believe in varying shades of truth
    now - if Toyota's PR dude would have been honest, and simply said, "but no one is distilling hydrogen from water because it's a wasteful use of electricity ... but we're still working on it" . . . than folks could live with that.
    .
     
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  7. bisco

    bisco cookie crumbler

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    hill, you're on a roll today!(y)
     
  8. usbseawolf2000

    usbseawolf2000 HSD PhD

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    What is the source of that information?

    Be sure to include storage of that electricity because H2 includes ability to store.

    3-5 mins refuel speed is only possible in hydrogen form. There is no perfect pathway. There are pluses and minuses.

    Electrolysis is one way. Photolysis is another way to produce hydrogen.

    One can make EV look inefficient by choosing the following path:

    Sunlight -> photolysis -> hydrogen -> fuel cell -> electricity -> battery -> electricity -> motor

    Just as you can make FCV look bad with:

    Sunlight -> photovoltaic -> electricity -> electrolysis -> hydrogen -> fuel cell -> electricity -> motor

    The best path for FCV is:

    Sunlight -> photolysis -> hydrogen -> fuel cell -> electricity -> Motor

    The best path for BEV is:

    Sunlight -> photovoltaic -> electricity -> battery -> electricity -> motor
     
    #8 usbseawolf2000, Jun 10, 2015
    Last edited: Jun 11, 2015
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  9. hill

    hill High Fiber Member

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    I'm not trying to be "on a roll" - & i don't like raining on hydrogen hopefulls. I'm hopefull, despite the apparent need to defy physics to make hydrogen economical. The FC lobby needs to be honest with the facts. With facts in mind, per usb's request, here you go
    Just How Energy Efficient is the Toyota Mirai? Time to do Some Maths - Transport Evolved

    Hydrogen efficiency is much worse via water/electric distillation - and less worse, via natural gas. That's pretty much a given. It's disingenuous for the hydrogen lobby to spin it otherwise ... even via omissions. Yes, cow poop, solar electric & other exotic hydrogen distillation processes technically are possible - and it's the technically possible that keeps getting pushed onto the public - not because the technically possible will ever be economical - but because it feels more technological than using non-renewable natural gas - which to date, and on into the foreseeable future, is the only way to burn up less energy to distill hydrogen.
    .
     
    #9 hill, Jun 10, 2015
    Last edited: Jun 12, 2015
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  10. usbseawolf2000

    usbseawolf2000 HSD PhD

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    As an owner of a plugin car and home PV system, I must say it paints an unrealistic rosy picture for EV that is not plausible. It paints a picture of Model S charged by solar electricity -- though possible but not plausible.

    The assumption made was, solar electricity could be generated at any time and stored and able to charge EV on demand. It is not and because of that, fossil fuel must be used to charge that Model S. Starting from the power plant with 280 kWh of energy, only 93 kWh would end up at the outlet. With 15% charging loss, it would allow 266 miles of driving. There is also vampire drain (1% per day) to consider.

    That is probably the worse case if the Model S is charged at night. However, it can be charged during the day but there is limited sun hours. If you were to charge at SuperCharger speed, you'll need 500 solar panels filled in a 9,000 sq. ft of roof, perfectly facing the sun.

    In reality, I think renewable electricity must be stored off-car. Either in PowerWall (home battery) or generation of hydrogen. It can then be used to charge the EV. PowerWall route would add cost and pretty much double the battery charge/discharge life cycles but PowerWall 92% efficiency would still make it preferable route for BEV but the refuel speed is limited at 2kW (43 hours charge).

    However, the hydrogen route would enable the stored hydrogen to refuel at 3-5 mins. The beauty of hydrogen is that it can be generated from many sources, including BS and STILL refuel like gas speed.
     
  11. austingreen

    austingreen Senior Member

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    I'm not quite sure of the source of this strawman.

    PV on roof and at some charging stations. Let's take a home charge at hills house for his leaf, but you can use the same reasoning for wind or solar that a tesla owner uses. Solar power is generated at the roof, lets say Hill uses 13 kwh a day on average to charge his leaf and built enough extra kw of solar on his roof for this. If hil charges his car while the panels are active, great he is charging directly, but lets say he is doing something better for the california grid and charges while he sleeps. Say 14kwh is then goes through a grid loss of about 7%, and someone uses it instead of natural gas generated electricity. That natural gas not used in an out of state plant during peak, is then offset by extra natural gas burned when hill charges his car, probably using more efficient local plants, and putting less strain on the grid. Still this gets that 7% grid loss so hill really needs to generate 14 kwh of solar to offset around the same natural gas as it takes to charge his car 13lwh. well he would but he probably has made his local grid more efficient in southern california YMMV.

    OK so 280 kwh * 93% efficiency is 260 kwh (hey that renewable for the hydrogen also probably will take this hit). Hill's leaf is more efficient but lets use the 101 mpge of the new tesla S 70d a much faster car with more interior seating than the mirai. 260kwh/33.7kwh/gge*101 mpge = 779 miles, close enough to 800 miles for government work.;)

    What about that 15% charging loss? The charging loss is included in the epa's mpge rating. You can't count it twice.
     
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  12. bisco

    bisco cookie crumbler

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    complete elimination of fossil fuels is unlikely, or at least way off in the future. it remains to be seen which forms of energy production and storage (if not all) will work out best for personal transportation. with the science though, is there any need for a climate change type of debate?
     
  13. austingreen

    austingreen Senior Member

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    I am not even sure why complete elimination of fossil fuel is the goal.

    NREL cut down their estimate of strong fcv penetration to 15% It is hard to imagine we will get to 50% fcv in the next 50 years in the US. If you force them all to be renewable I doubt that 15% is viable, it probably would be much cheaper to build long range bevs if we count the solar panels and wind turbine cost to get to 15%. Tesla has found nobody cares to use their swap station, so this fast charge is more government hype than real requirement. No why not just admit that hydrogen is much cheaper when made from methane, and even california is 67% natural gas as a goal, and that much renewable is making the test much more expensive.