• JohnDClay@sh.itjust.works
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    1 year ago

    Hydrogen never really made sense for cars, the infrastructure and storage is too expensive. But I wonder if it’d work for trains that haven’t been fully electrified with overhead cables yet. You’d need much less infrastructure at just a few locations.

    • Kuinox@lemmy.world
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      1 year ago

      On the other hand, my city is trying hydrogen bus.
      There is a single refilling station needed.

      • JohnDClay@sh.itjust.works
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        1 year ago

        Oh that’s a good idea too. If the hydrogen and electricity is green, it’d have less of an environmental than batteries.

        • Pxtl@lemmy.ca
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          1 year ago

          It isn’t. The amount of green hydrogen is a fraction of a fraction a percent of all hydrogen. The rest is all made from natural gas and the CO2 is released into the air. It’s a green washed fossil fuel.

          • jasory@programming.dev
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            1 year ago

            “Green hydrogen”, is also incredibly inefficient in its own right. Approximately a 70 percent loss of energy compared to 15-20 percent for battery storage. It would literally be just as efficient to burn natural gas in a power station (with a 50+ percent efficiency, modern power turbines are very efficient) and use that power to charge a battery. The entire “hydrogen economy” has been a pipe dream by either complete morons or fraudsters (probably both). (Hydrogen aeroplanes might actually work, but that is by combustion and jet engines are already very efficient).

          • JohnDClay@sh.itjust.works
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            1 year ago

            But if they’re making the stations, they can use or manufacture green hydrogen. It just a matter of the political will.

            • ch00f@lemmy.world
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              1 year ago

              But if they’re making the stations

              But they’re not. See: this article. They’re not profitable, and if they ever were, it was propped up by greenwashing a byproduct of natural gas production.

              • JohnDClay@sh.itjust.works
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                1 year ago

                The article didn’t link. Also, not profitable compared to what? Because running at a slight loss to decrease ghg emissions would still be worth it. Are there fully electric battery alternatives to use instead?

                • ch00f@lemmy.world
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                  1 year ago

                  I’m referring to the article posted in this post. Stations are being shut down because they aren’t profitable. It doesn’t have to be compared to anything. If they can’t make hydrogen cheap enough, they can’t sell enough and they can’t sustain the business mode.

                  The cheapest way to make hydrogen now is as a byproduct of natural gas production which is not as eco-friendly as anybody would hope.

                  Hydrogen for consumer use is a boondoggle and waste of time. BEVs are here and work great on existing infrastructure (for L2 charging at least). I drive an EV and exclusively charge it at home. No special station required.

                  • JohnDClay@sh.itjust.works
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                    1 year ago

                    Absolutely. That’s what I said originally. Consumer use never made sense. But busses or trains might still make sense since they’d have much more centralized infrastructure.

        • Pipoca@lemmy.world
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          1 year ago

          Today, green hydrogen is essentially an expensive, low-efficiency battery.

          That could change with future work on making more efficient hydrolysis, but today, the numbers really don’t work out on green hydrogen vs alternatives like lithium ion or overhead wires for busses.

          • JohnDClay@sh.itjust.works
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            1 year ago

            But a hydrogen battery has much much better specific energy than lithium ion. So you can have a much longer range.

            • Pipoca@lemmy.world
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              1 year ago

              Hydrogen is very light, so the energy per kilogram is quite high.

              However, hydrogen is also naturally not very dense. Hydrogen at 1 atmosphere has a tiny fraction of the energy of a similar volume of batteries. Pressurized hydrogen is similarly dense to a battery, and liquid hydrogen is about twice as dense.

              So to make hydrogen dense, you need a very thick, heavy tank to hold the pressurized hydrogen. That significantly cuts into your weight advantages.

              Add to that, fuel cells are very inefficient at converting hydrogen to usable electricity.

      • JohnDClay@sh.itjust.works
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        1 year ago

        How do battery operated work? Are they short rage trains? Or do they have like a car full of batteries? And how do recharge times work? Can they recharge just in the stations? If it works for them, great. And it sounds like it is. It just seemed like there were several problems.

        • Pxtl@lemmy.ca
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          1 year ago

          Battery locomotives don’t have enough range to be useful solo, but they’re a handy to add on to an existing train to give it regenerative braking and improve it’s efficiency.

          You want practically zero emissions train, you build overhead catenary wires. But that’s decades old tech that just works, it’s not sexy futuristic stuff.

          • BarelyOriginal@feddit.nl
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            1 year ago

            I don’t know, have you seen those wires above the rails? They always look sexy and futuristic to me, especially the high speed rail ones 🥵

          • JohnDClay@sh.itjust.works
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            1 year ago

            I was saying it seems to make sense to use hydrogen as an intermediate step before you can put in all the infrastructure for overhead wires. If Germany is just using electric engines plus diesel engines now, instead of hydrogen engines, then there’s still emitting a whole lot more than they would otherwise. Even if it is cheaper.

            • Cethin@lemmy.zip
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              1 year ago

              There’s no way Hydrogen in Germany would be more green than diesel. It’d just be greenwashing. You’d need to make electricity to make hydrogen, store it and transport it, then turn it back into electricity (that’s how a hydrogen engine works, not by burning it). In the mean time, Germany is increasing it’s production of dirty energy, so the hydrogen production would have to be done with dirty energy. There’s no way that process is more efficient than just using diesel directly.

              It might be better somewhere else, but not in Germany.

              • JohnDClay@sh.itjust.works
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                1 year ago

                You don’t need to use the standard grid energy. You can use off peak power rates in areas with a lot of wind, so it’d use the otherwise unusable energy. Or you could disconnect from the grid entirely. But the power source is absolutely a concern.

                What would the co2 trade off look like between diesel and hydrogen? Diesel you’d have a constant co2 per mile, whereas hydrogen would have higher kwh efficiency, but high conversion inefficiency, then some percentage of the energy emits co2 at a certain rate. I don’t have time to crunch the numbers now, but I would be surprised if hydrogen was more ghg intensive.