• Voyajer@lemmy.world
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    3 months ago

    I’d be interested in home scale hydrogen electrolysis with excess solar energy even if only to sidestep the “use it or lose it” reality of off-grid solar.

      • stabby_cicada@slrpnk.net
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        3 months ago

        Thing about batteries is.

        From an environmental standpoint, both mining the raw materials and producing the batteries uses a lot of energy and produces a lot of pollution.

        Morally, many raw materials for batteries come from desperately poor conflict zones, so you have megacorps staffing mines with slavery and child labor, paying local warlords/dictators for permission to operate, having those warlords/dictators kill protesters and union organizers, etc.

        If we can get a hydrogen economy working, and the equipment and technology don’t need conflict minerals or polluting heavy industry to manufacture, it would be a boon for the world both practically and morally.

        But that’s a big if.

        • frezik
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          3 months ago

          Hydrogen fuel cells need rare earth metals, too. Sodium and iron air batteries, in contrast, don’t need a whole lot. For that matter, lithium batteries are opening up more abundant sources. People misunderstood what “reserves” means for minerals.

      • MrMakabar@slrpnk.net
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        3 months ago

        Hydrogen can be stored in underground caverns and that can be relatively easily scaled to TWh. Electrolysis and fuel cell can get you 70% or so of your electricity back. So it is less efficient then batteries. However there might be a place for hydrogen as seasonal storage. Also the storage makes sense as quite a few processes use hydrogen anyway.

        So there is a use case, but right now we mostly should just add renewables and batteries. We are nowhere close to a solar/wind grid, which does actually need seasonal storage. Also grid size helps a lot and there are options such as burning waste.

        • frezik
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          3 months ago

          Electrolysis of the most expensive process (PEM) is around 80% efficient by itself. The more common methods are 70%. Anything that uses it after that only drops it further. Fuel cells max out at 60%, which means that electrolysis to electrical output efficiently is about 50% altogether in the very best case.

          Some of the better internal combustion engines are reaching about the same.

      • Voyajer@lemmy.world
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        3 months ago

        After my batteries are charged. I have 40kW, but excess would probably go toward the diesel powered implements I have, that way they can run more efficiently and reduce emissions.