Can’t you just break down water, use the hydrogen to power the electric motor, and I don’t think O2 as a byproduct is bad, now this is of course an ideal condition, but why hasn’t this been looked into more?

  • Gigan@lemmy.world
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    5 months ago

    I’m not a chemist/physicist, but if I had to guess it’s because it takes more energy to break apart the water into Hydrogen than what you will get by burning the Hydrogen to power the motor.

    • BlameThePeacock@lemmy.ca
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      5 months ago

      Your guess is accurate.

      The other side of the issue is that “water” is rarely only water. There are tons of other shit floating in the water that cause problems with the splitting process, so you usually have to clean the water first which takes even more energy/resources.

    • JoeCoT@kbin.social
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      5 months ago

      Correct. Splitting hydrogen from water is quite energy intensive. Burning hydrogen into oxygen to make water releases energy, but not as much energy as it takes to split the hydrogen off in the first place. The reason to use hydrogen fuel cells is that the extra energy needed to generate the hydrogen is still far better than the carbon output and costly materials needed for making and charging a battery. Batteries need rare earth metals, and they lose their charging ability over time. Splitting water into hydrogen creates “potential energy” from the later creation of water again, making it a useful, clean way to store electricity.

      Same as the plans for using cranes stacking concrete bricks to store electricity. It takes more electric to stack them than is produced by unstacking them. But it’s a clean way to store potential energy, and far more efficient and sustainable than a battery.

      • TropicalDingdong@lemmy.world
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        5 months ago

        The reason to use hydrogen fuel cells is that the extra energy needed to generate the hydrogen is still far better than the carbon output and costly materials needed for making and charging a battery.

        This is just absolutely a false statement. Hydrogen is a carbon fuel, because all of it for practical purposes comes from natural gas. Although it is possible to get hydrogen through electrical hydrolysis, this simply is not where hydrogen as a fuel source comes from today.

        If you see or hear hydrogen being discussed, translate the word hydrogen to mean ‘natural gas’ or fossil fuels, because that’s what you are actually talking about. We do not currently get hydrogen as a fuel by splitting. We currently get hydrogen as a fuel by splitting hydrogen from natural gas. You would likely be better off just driving a gas car than a hydrogen powered if your goal is overall emissions reductions. Batteries represent an actual renewable technology because right now (not hypothetically) we can and do power the electrical networks that charge them with renewables. In as far as renewable hydrogen is concerned, there basically is none, because it costs so much more so to produce in this manner than it does to get hydrogen from fossil fuels.

        • JoeCoT@kbin.social
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          5 months ago

          Correct. Green hydrogen is expensive and energy intensive, and is not as cost effective as getting it from natural gas. So currently most hydrogen comes from natural gas.

          But, unless we find ways to make batteries without rare earth metals, we will be better suited to moving towards fuel cell, once we have the excess electricity from renewables needed to split hydrogen from water. For now, batteries are the better option.

          • TropicalDingdong@lemmy.world
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            5 months ago

            Yep. Just wanted to get it out there because there are active propagandists promoting H2 as it’s an extant carbon neutral technology ( I expect Hypx to show up any moment). I’m not arguing against potential but trying to ground the conversation in material reality.