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      CommentAuthorTrim
    • CommentTimeAug 25th 2018
     
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      CommentAuthorping1400
    • CommentTimeAug 25th 2018
     
    Yes, finally some reason and logic in the hydrogen vs battery debate.

    Hydrogen may become important in seasonal storage. To use the abundance of solar in summer to create hydrogen that is stored in old natural gas fields and to be used in the winter months.

    But for daily or weekly cycles, like day-night for homes, or for transportation purposes, it is indeed very inefficient.


    The classical argument is that the electricity used to charge a car is produced by coal power plants, with an efficiency of 42%. Then you add the grid losses (about 6%) and the losses in the charger inverter and battery (another 10% for the load-use cycle). In the end you have 35% effective energy for the electric drive left. In this example the electric car has almost the same CO2 emission as a traditional diesel car.

    The efficiency of converting coal to hydrogen is about 70%. The hydrogen distribution losses are 8% (compression and leakage). The losses in the fuel-cell to turn the hydrogen into electricity for the car engine is about 50%. In the end you have 32% effective energy for the electric drive. This is slightly less than with the battery car.


    But this classic comparison is wrong. It is old world thinking. In the near future over 50% of electricity production will be from wind and solar energy. Here the primary production product is already electricity, not coal or natural gas. And when the solar production is local, the grid losses are also less than in the classic example.

    In this world the main losses of the electric car with a battery are for charging (about 10% for the load-use cycle). We can add some 3% grid losses for fairness. The overall cycle now has 87% effective energy for the electric drive.

    Now do the same for a hydrogen car, sourced by wind and solar energy. First you lose at least 3% in grid losses transporting the electricity (depending on the measure of decentralization of the hydrogen production). Then you lose 20% in the electrolysis and 8% in compression and storage. The losses in the fuel-cell to turn the hydrogen into electricity for the car engine is about 50%. In the end you have 35% effective energy for the electric drive. This is 2,5 times less efficient than the battery car!


    Conclusion: in the old fossil world there is hardly difference in primary energy efficiency between hydrogen and battery cars. When forgetting all the bad stuff about hydrogen, you could argue it is more convenient as you can fill up in 5 minutes.

    However in the new renewable world the battery car is 2,5 times more efficient than the hydrogen car. Exit hydrogen. No need to discuss all the other bad stuff about hydrogen as a fuel for cars.
    • CommentAuthorAsterix
    • CommentTimeAug 25th 2018
     
    Every time I view a presentation on hydrogen, it seems that the energy density is quoted in terms of units per mass (e.g. kcal/kg). No one seems to start off by quoting units per volume.

    Hydrogen is quite energetic, but there's far more hydrogen in a liter of gasoline at STP than there is in a liter of liquid H2 at -259C.

    There are other compounds that store hydrogen nearly as efficiently as hydrocarbons, ammonia being one of them. I wonder why little effort has gone into that? Ammonia has been produced industrially for a very long time.
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      CommentAuthorAngus
    • CommentTimeAug 25th 2018
     
    Smelly, toxic. I was glad to get rid of the carbide lamp on the pennyfarthing.
    • CommentAuthorAsterix
    • CommentTimeAug 25th 2018 edited
     
    Yabut acetylene doesn't pack much hydrogen per molecule in relation to carbon. Methane is twice as good in that respect. I suggested ammonia because of the carbon-less nature, although busting that nitrogen bond is a bugger.
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      CommentAuthorTrim
    • CommentTimeAug 25th 2018
     
    Formic acid is also good, with advances in nano tech milking ants is no problem.

    Fuel cells can also run on methanol.

    Hydrides can be used to store hydrogen but they still have problems, the ones that store hydrogen quickly tend to release it slowly and the ones that release it quickly store it slowly, new meta materials are needed that can both store and release quickly on demand.

    In laboratories using sunlight to produce hydrogen by splitting water is becoming somewhat more practical.
    • CommentAuthorAsterix
    • CommentTimeAug 25th 2018
     
    The problem with formic acid or methanol is that you're paying freight for oxygen--that is, the fuel is already partially oxidized. Isobutane would probably pack the biggest punch per buck.
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      CommentAuthorTrim
    • CommentTimeAug 25th 2018
     
    Oh well, I guess batteries will just have to be Goodenough.
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      CommentAuthorTrim
    • CommentTimeAug 25th 2018
     
    Posting about laboratories.

    Sugar, Light, And A New Type of Chemistry — What It May Take To Wean Us Off Fossil Fuels.

    https://futurism.com/biolec-new-chemistry/
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      CommentAuthorTrim
    • CommentTimeAug 25th 2018
     
    Progress to lithium-oxygen batteries with up to four times the energy density of lithium-ion.

    https://www.nextbigfuture.com/2018/08/progress-to-lithium-oxygen-batteries-with-up-to-four-times-the-energy-density-of-lithium-ion.html
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      CommentAuthoraber0der
    • CommentTimeAug 25th 2018 edited
     
    They think their audience is stupid:

  1.  
    :/
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      CommentAuthoraber0der
    • CommentTimeAug 25th 2018
     
    :|
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      CommentAuthoraber0der
    • CommentTimeAug 25th 2018
     
    The WH staff calls Trump's sensory deprivation tank a 'fool cell'.
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      CommentAuthorAngus
    • CommentTimeAug 25th 2018
     
    He's deprived of sense without any need for a tank.
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      CommentAuthoraber0der
    • CommentTimeAug 25th 2018
     
    He's also officially certified as 'SpongeBrain SquareWig'.
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      CommentAuthorTrim
    • CommentTimeAug 26th 2018
     
    And he is your leader, says so much about your country, you must be so full off pride?
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      CommentAuthoraber0der
    • CommentTimeAug 26th 2018
     
    He is; we are. We're winning so much it almost boggles our minds!
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      CommentAuthorTrim
    • CommentTimeSep 3rd 2018
     
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      CommentAuthorAngus
    • CommentTimeSep 3rd 2018 edited
     
    Posted By: aber0der We're winning so much it almost boggles our minds!

    Just to say...my mind is fully boggled by Wee Donald.