This past week, I attended the Micromobility Europe event in Amsterdam, where I saw many familiar company faces and several…

  • colourlesspony@pawb.social
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    5 months ago

    Maybe? Warning Half-asses napkin math here but there are 286 KJ in a gram of hydrogen. So that 20 grams has 5720 KJ which converted to Watt hours is 1589 Wh. From my googling hydrogen fuel cells are 40 - 60 percent efficient. So half that to 750 Wh. Which is comparable to most e-bikes rated for 20Km of range. There are some issues with hydrogen. Converting water to hydrgron is only 70-80% efficient and converting that hydrogen to electricity is 30-60 percent efficient. Compare that to li-ion battery which can be charged at close to 99%. That mean hydrogen waste so much more electricity. Which is why I’m a hydrogen hater. I much prefer putting solar energy directly into batteries instead of the converting it hydrogen and back again at great lost.

    • girsaysdoom@sh.itjust.works
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      5 months ago

      Your hydrogen efficiency estimates are probably pretty close to what this bike can do. The lithium ion comparison is missing some losses, ~90% efficiency from voltage boost converter. Also, the hub motor/speed controller both add another 75% efficiency to the equation but this applies to both so we can negate it.

      As for being a hydrogen hater, what did hydrogen ever do to you? I think we’d all prefer a solid state solution that would minimize losses but we don’t have enough battery infrastructure to accommodate all of our needs. Sure, hydrogen is not the panacea for fossil fuels or lithium batteries in cars but there are good uses for it. I think Hydrogen can potentially be a good replacement fuel for large shipping vessels like ships and trains, since size requirements aren’t as much of a factor, or used in grid storage as a long term or spillover storage for renewable energy when battery infrastructure is at full utilization and other means aren’t available.

      • colourlesspony@pawb.social
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        5 months ago

        I didn’t think about hydrogen powered shipping container ships. That sounds like a good use case.

        My main issue with hydrogen is that most of it is produced using some natural gas / fossil fuel thing I don’t understand. AKA Dirty hydrogen. Producing hydrogen using green tech is super inefficient compared to storing green energy in batteries. Personally, I think better battery tech like sodium Ion that uses cheap and recyclable materials are the better option for most applications.

        I do have a personal conspiracy theory that fossil fuel is pushing for hydrogen to slow green tech epically since the cheap way to make hydrogen is with fossil fuels.

        Another thing about hydrogen is storage and transportation. To store it long term you need to cool it a liquid form which is really hard to do. Also, current hydrogen fuel cell are low efficiency and low power density. That’s why the toyota miria uses a fuel cell to charge a battery which powers the car.Tthe fuel cell can’t put out high current.

        Most of what I know about hydrogen tech came from the aging wheels video about Mirai. So I might be super wrong about everything. I do recommend giving it a watch though: https://www.youtube.com/watch?v=rtZQLUtckS4

        • girsaysdoom@sh.itjust.works
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          5 months ago

          You’re definitely not wrong. Gray hydrogen currently is the most common source, which is a byproduct or an intended product of petroleum cracking. This also is probably a reason why most petroleum companies chose to research hydrogen in the 2000s/2010s rather than battery or other renewable technologies, since it fits nicely in their existing pipelines.

          For storage, I’m pretty sure you can keep it at atmospheric pressure and temperature if space isn’t an issue, but to actually fit it in a vehicle you’d probably have to use one of the techniques you mentioned.

          The Mirai’s issues seem to be that it was just a foothold for consumer hydrogen without anything really backing it. You could almost say the same about EVs/PHEVs 15 years ago and look at them now.

          Honestly though, if we are able to scale up sodium batteries, grid storage and train usage might be moot. Ships could probably still use it as an alternative to diesel though.