[shuntress]

If your goal is to store 100% of all power produced for an entire year for use a later date, then yeah... you would need 50,000+ of those.

If your goal is something not ridiculous, for example, storing storing the difference of production-consumption when production>consumption for use later when consumption>production, you would likely need very significantly less than 50,000+ of those.

[oblio]

My point is that these need very specific conditions to actually work and you need a lot of them.

For your average country even having 100 is difficult. Think of some flat place like Poland.

More than that, Germany isn't even the biggest producer/consumer of electricity... Imagine some place like China trying to ramp this up.