theoretically, compressing gas is energyless. Ie. you get back exactly the same amount of energy when decompressing as you got when compressing, so you should be able to do it with no loss.
Practically, that's fairly far from true for today's technology. Gas is so cheap that we're happy to waste a bunch of energy to make the plant cheaper.
Practically, that's fairly far from true for today's technology. Gas is so cheap that we're happy to waste a bunch of energy to make the plant cheaper.