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World’s largest compressed air energy storage project comes online in China
(www.pv-magazine.com)
this post was submitted on 17 May 2024
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Wouldn't this be horribly inefficient?
The tldr says 72% efficient. If it can store excess solar or wind from times they are not in use and release at times of higher demand, it should be great.
Better is always on the road to perfect.
Yeah that isn't as horrible as I had initially thought, though its still not great
You are right though something is better than nothing, but I wonder how this facilities cost compares to an equivalent battery storage facility
In all of this, we need diversity. Diversity of generation sources (solar, wind, tidal, etc). Diversity of storage (Chemical batteries, compressed air batteries, pumped hydro, etc). Each will have different sweet spots; cost vs reaction time vs capacity vs efficiency.
Try not to dismiss a technology just because it's not the whole solution. Nothing ever is. They all contribute a part to the big picture.
Compared to what?
pumped water or flywheels maybe? you lose a lot of energy compressing gas to heat dissipation.
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.
Round trip efficiency of modern pumped storage hydro is about 80%. How is that horrible if 72% is decent?
Pumped hydro obviously does have drawbacks in that it requires you to have the water and suitable landscape available to dedicate to it, but efficiency doesn't seem to be one of them
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 a good trade to me.
If you have a good heat exchanger, don't you get most of that energy back when expanding the gas?
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...
I was thinking of lithium or sodium ion battery storage
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.