It seems to me pumping out water to near vacuum while under crushing outside water pressure would be a significant power hog
Well, yeah. That’s the point. It’s a battery. Whatever energy you put in to pump the water out, you get some percentage (probably in the 50-70% range) of it back when you let the water back in. The point of these is to store energy from renewables whenever they are providing more power than the grid demands - otherwise the power would be wasted.
Edit: The paper claims 72% efficiency which is pretty good if I understand things correctly
Yeah don’t get me wrong- I get it’s a battery. But a battery that’s 5% efficient isn’t great. Now 72? That’s pretty incredible, I’d like to see that in action.
Well, yeah. That’s the point. It’s a battery. Whatever energy you put in to pump the water out, you get some percentage (probably in the 50-70% range) of it back when you let the water back in. The point of these is to store energy from renewables whenever they are providing more power than the grid demands - otherwise the power would be wasted.
Edit: The paper claims 72% efficiency which is pretty good if I understand things correctly
Yeah don’t get me wrong- I get it’s a battery. But a battery that’s 5% efficient isn’t great. Now 72? That’s pretty incredible, I’d like to see that in action.