[IAmBroom]

As always, the question is not "do this for solar, or not?". The question is, "Is this a valuable & efficient way to store energy?".

It has to compete with pumped weight (usually water), pumped heat (salt, water, or underground), electric batteries, and so on.

So, as always, it's complicated.

[coryrc]

I would say your question needs to be expanded to "Is this a valuable & efficient way to store energy which can be scaled to any location?". The pumped options aren't. Batteries are cost-effective for time-of-day shifting, but not long term. Electrolysis and gas tank storage can be built in any climate, any terrain. Then benefit from economies of scale while the others are stuck in niches.