[algo_trader]

Pumped hydro can amortize over 50-100 years. In a true renewable grid, you will get over 50,000 cycles from the same dam (with some turbine replacements).

EDIT: numbers..

[Schroedingersat]

Thermal degradation will likely take it out before 100 years, but odds of wearing out next gen sodium ion batteries by cycling are pretty slim https://natron.energy/product/

[zizee]

How much labour is involved in the upkeep/operation vs a battery bank?

I think that there are pros and cons of each, we'll end up with a mix of lots of different solutions.