From what I've read batteries are the preferred option for short-term zero-emissions levelling but once you get into longer term stuff you start looking at storing compressed air or hydrogen in salt caverns. But hydrogen cracking/storage as a grid-level utility is still at the experimental stage.

Power-to-gas (Hydrogen or Methane) as battery is from my perspective only viable solution. Everything else appears to be more or less elaborate attempt to suck subsidies, but provide inadequate system.

Here is a cool pipe dream: https://heindl-energy.com/

The only gravity storage that isn't nonsense is pumped hydro.

https://www.youtube.com/watch?v=iGGOjD_OtAM