Amusingly, modern hydraulic accumulators of a different sort may still have a role in power generation. I'm working on a couple of wave generator projects where the waves pump hydraulic rams, storing pulses of pressure in hydraulic accumulators, where it's then used to drive a generator at a more constant speed.

Intresting, though wave power is a minusculy small overall altrnative energy source with massive capital feqirements. There are better options to pursue.

Pumped hydro is ... after a fashion ... a vastly more appropriate hydraulic accumulator, as is CAES.