Inspired by TheBamForth's and pocmloc's very clever ideas
Use part of the turbine's power to pump air into the storage area above the piston, push the piston down into the deep well and when needed, let the water pressure at depth push the piston, and air back up to be used.
Cheaper than storing the water in a tank or building a diving bell to store the air and you can increase the volume, storage capacity and pressure as needed by going deeper with your piston well. And unlike a simple diving bell style tank, you're pretty much unlimited in how big this thing could be. It could also be easily extended as necessary.
See link for TheBamForth's and pocmloc's ideas this evolved from.
ADDENDUM: Piston could be charged either by an air pump or simply pulling the piston down with cables.-- doctorremulac3, Jun 09 2020 The ideas this evolved from. Hollow_20wind_20tur...ich_20store_20water [doctorremulac3, Jun 09 2020] A review of underwater compressed air storage http://euanmearns.c...ressed-air-storage/ [xaviergisz, Jun 12 2020] kdf, are you saying a piston exposed to the open ocean and utilizing the ocean water pressure as the "spring" to store the energy has been done before? I'm not seeing it in your link. It might be there but I didn't see it at first glance. Seeing the balloon as being proposed but not the exposed piston.
But maybe I missed it.
If it HAS been proposed, gotta wonder why nobody's done it. Storage of intermittent energy generation systems like wind and solar is a big issue.-- doctorremulac3, Jun 09 2020 That's fine, I appreciate it. I WANT to know if this has been suggested before.
Kind of surprised that it hasn't frankly.
By the way, see addendum for how the piston would be filled. You could use an air pump, but, you could also just have a motor pulling the piston down. Very simple.
Then it wouldn't be a compressed air storage until you let the piston go.-- doctorremulac3, Jun 09 2020 Mechanically moving a piston to displace sea water at high pressure would need to seal the upper air chamber at a considerable differential pressure - very difficult to do well. OTOH, an air pressure driven piston would only need to prevent/reduce diffusion at the air/water interface as the pressures would be the same. In any charge-discharge cycle, with time, such diffusion would reduce system efficiency.
It might be useful to compare the efficiency of an air turbine versus a piston engine - where the engine is made up of a series of bladder type pistons, sequenced via pneumatic valves. The attempt would be to minimized losses to those resulting from adiabatics.-- manwhojaped, Jun 12 2020 I'm not seeing why you need the piston at all. Compressed air will quite happily sit above water, so just pump air into the open-bottom tube and let the seawater find the balance.-- neutrinos_shadow, Jun 12 2020 Hey, [manwhojaped]; welcome aboard.
Use the return key for social distancing and sanitise your elbows whem you've finished. ;-)-- pertinax, Jun 12 2020 [manwhojaped] Welcome and I sincerely thank you for making me look up a word.-- Voice, Jun 12 2020 //just pump air into the open-bottom tube// That is what I suggested originally, and then improved by suggesting instead pumping water our of the top of said tube.-- pocmloc, Jun 12 2020 Yea, [manwhojaped]; welcome aboard.
Interesting annotation, that's what I come here for.-- doctorremulac3, Jun 12 2020 you people are awesome! you make me think - and I am grateful of the exercise.-- manwhojaped, Jun 14 2020 [pocmloc]; so you did. I must have missed the last comments there somehow. So a big hole in the ocean; re-generate power by letting the ocean fill it back up...-- neutrinos_shadow, Jun 15 2020 random, halfbakery