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The momentum of the solar energy transition
(www.nature.com)
Due to technological trajectories set in motion by past policy, a global irreversible solar tipping point may have passed where solar energy gradually comes to dominate global electricity markets, without any further climate policies
So that are the numbers for dams (since pumped storage is extra and much smaller). That is not (electrically) rechargable storage. It is storage, but bound to the influx of water and with many constraints about how much water can be released at what point, how much it has to have at least or at most at which point in year to prevent floods or droughts etc. That is not the kind of storage we need for solar and wind. And while the storage capacity is high, the available power output is not. Since they maximum anyone would install is going to be correlated to the influx of water, not to the fastest possible draining of the reservoir - which nobody would ever want to do.
Also, thank you for the interesting discussion.
Most of that is fine during a dunkelflaute. The only really big issue is not having enough generating capacity, but even that likely works out. The most fuel generation during a single week last year was 24,302GWh so 144GW running throu. Sweden and Norway can generate 49GW in hydro at full power. Even the best weeks still have over 12TWh of fossil fuele generation in the EU, so that certainly goes a long way to solving the problem of dunkelflaute.
But you are right, most of the year smaller storages to cover a night or so, is all you need. So you still want some TWh of battery and pumped hydro storage. That preserves hydro storage and is needed to balance the grid. Biomass is also worth a look for long term storage.