• mercano@lemmy.world
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    1 day ago

    Wouldn’t it be more energy efficient to just electrify the line rather than charging & hauling around batteries? The technology has been around since *checks notes* the late 1800s.

    • Ptsf@lemmy.world
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      1 day ago

      Not to mention trains are a particularly good candidate for hydrogen fuel cells.

      • SomeoneSomewhere@lemmy.nz
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        13 hours ago

        Hydrogen has a major efficiency problem. Unless the electricity to create the hydrogen is practically free (i.e. grid price is zero, you’re turning off generators) it’s not worth it. You’re at like 30% round trip efficiency whereas batteries and overhead lines are well above 90%.

        Using hydrogen also prevents regenerative braking, which is one of the big advantages of battery or overhead electric.

        • Ptsf@lemmy.world
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          8 hours ago

          True, but eletric overhead has significant upkeep and initial investment costs, as well as pure grid reliance. Batteries have significant weight, cost, and technical requirements combined with a relatively low lifeapan. Every energy system is going to have it’s downsides. Hydrogen fits well in train use cases because they often rely on being able to fuel relatively quickly (low downtime means less expensive engines required), operate in areas with unreliable grids (urban through shipping), and it has a relatively low initial investment cost (about on par with regular diesel). Hopefully it would be generated with on-site renewables, but we’ll cross that road when we get to it. Oh, and another thing people often forget about batteries is that once you account for losses in transmission, voltage conversion, and charging it ends up being significantly less efficient. I’ve been unable to find exact statistics for this in % though.