Gravity storage: pumped hydropower for flatlanders

This is a very interesting energy storage concept. It promises large capacity (up to 10GWh), with very favorable scaling. It also allows scaling power and capacity independently (unlike most batteries).

Main drawback is that it still needs suitable local geology.

A big obstacle is that you can not build this economically at small scale, so it's probably quite difficult to find investors (=> need to build uneconomical, small pilot plant first).

I wish governments would throw some money at this concept specifically. This could potentially complement battery storage very nicely (with comparably higher capacity at lower power).