Comment on World’s largest compressed air energy storage project comes online in China

• captain_aggravated@sh.itjust.works ⁨6⁩ ⁨months⁩ ago

  pumped water or flywheels maybe? you lose a lot of energy compressing gas to heat dissipation.

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  • Diplomjodler3@lemmy.world ⁨6⁩ ⁨months⁩ ago

    Well, no. The round trip efficiency of pumped hydro is terrible. And flywheels aren’t scalable. 72% is pretty decent and I’m sure that can still be improved.

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    • Skua@kbin.social ⁨6⁩ ⁨months⁩ ago

      Round trip efficiency of modern pumped storage hydro is about 80%. How is that horrible if 72% is decent?

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      • wewbull@feddit.uk ⁨6⁩ ⁨months⁩ ago

        Energy density is terrible of pumped hydro, plus you have the environmental impact; tunnel out the inside of a mountain, place a generator hall in there, and then flood a valley. Sure it look ok at the end of it, but huge damage has to be done each time. All of that coats large sums of money too, and it can only be done in a relatively small number of locations. Step 1. You need a mountain to pump the water up.

        Compressed air batteries are a lot more energy dense, so smaller footprint, so much lower environmental Impact / cheaper and they don’t rely on particular geographic features to work. They might be a bit less efficient, but that seems like agoodd trade to me.

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  • threelonmusketeers@sh.itjust.works ⁨6⁩ ⁨months⁩ ago

    If you have a good heat exchanger, don’t you get most of that energy back when expanding the gas?

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    • captain_aggravated@sh.itjust.works ⁨6⁩ ⁨months⁩ ago

      What does “a good heat exchanger” look like in this case? You compress air, the pump heats up, so you ventilate it to keep it cool. The air in the tank is hot, and starts to cool as it sits in the tank, and this causes a decrease in pressure, which is why even with no leaks a shop air compressor will run for awhile, stop, then after awhile cut back on again.

      I get that I’m applying a shop tech’s “machines that I can move with a hand truck” understanding to factory-size operations here but…

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• kaboom36@ani.social ⁨6⁩ ⁨months⁩ ago

  I was thinking of lithium or sodium ion battery storage

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  • wewbull@feddit.uk ⁨6⁩ ⁨months⁩ ago

    It would take 460 Tesla Megapack 2 XLs to be the same capacity as this. The biggest deployment so far of those is about 200 Megapacks 1 giving 450MWh capacity vs 1,800MWh for this.

    The lithium batteries can supply the same power (300MW) and cost $160M. This cost $207M, so quite a lot cheaper given 4x the capacity.

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