The issue is always energy density and round-trip efficiency, and I don't see numbers for either of these. Remember that you do have to actually liquify the air first, and that takes power.
Been loving this channel for a while. Coolest video is them flooding a forest and showing fish swimming underwater, but above a forest floor. Real trippy.
In Australia, we call them "leaky weirs" (check dams too) as beavers don't exist and they were popularised by Natural Sequence Farming and Peter Andrews with great effect. Don't let the name fool you, they aren't that leaky and are built similarly to this vid.
I don't know if I like the term beaver dam as it's a bit exclusionary but if it works for clicks and techniques for the northern hemisphere, that's cool.
I've just included some old videos, NSF has been around for a long time:
yt.artemislena.eu
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