9 votes

The FactoBattery

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  1. skybrian
    (edited )
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    From the article: … … … Also, local abundance is an arbitrage opportunity, but actually doing the arbitrage might be more expensive than it’s worth.

    From the article:

    This brings us to the factobattery. The idea is simple: take a factory whose primary input is electricity, and overbuild it by 4x. Run it at 4x capacity during daylight and turn it off at night. Overall, this 4x factobattery is indistinguishable from a 1X factory in terms of its output. The “battery equivalent cost” is then 3x the factory cost.

    One example is an aluminum smelter, which consumes electricity to electrolyze aluminum oxide/carbon into aluminum metal and carbon dioxide. I picked aluminum smelting as an example because it’s responsible for something like 3-5% of worldwide electricity consumption, but it turns out to be a very bad factobattery.

    Another more favorable example is an electrolysis-driven fertilizer plant. …

    In this analysis, overbuilt electrolysis is a third as expensive as lithium-ion batteries, and comparable to peaker plants in cost! Yet, this does not imply that it is economically worthwhile to build an electrolysis-fed Haber Bosch plant. It merely says that, if you’re already building an electrolysis-fed Haber-Bosch plant, then you could overbuild its electrolyzers and provide competitive battery services.

    Proponents of the hydrogen economy talk about many other uses for hydrogen, like fuel cells, power plants, transportation, etc.. I think most of these ideas are silly (and this guy agrees). Hydrogen gas is just not dense enough of a physical material to be worth transporting, and you incur heavy conversion losses when turning it back into electricity.

    The electrolysis/hydrogen buffering factobattery works well because the hydrogen is directly consumed in a downstream industrial process. This means we don’t need to transport hydrogen, we don’t need fuel cells to recover the energy, and we only suffer conversion losses of electricity <-> hydrogen once, not twice.

    The biggest lesson in this is that “free” energy is not really free. You need to build the machines that will consume that energy, and they are often expensive enough that free energy isn’t enough of an incentive.

    Also, local abundance is an arbitrage opportunity, but actually doing the arbitrage might be more expensive than it’s worth.

    1 vote