Hi Hendrick. The technology is there, flywheels have come a long way.

https://medium.com/the-treatise/flywheel-energy-storage-system-c49aa34ead73

Further, the ultimate target has to be a world solar grid, around the equator, after which no regional energy storage is needed.

With money-as-sunlight (Proof of work tokens from solar power), there is no limit to how much can be spent, expense is no longer an issue.

Superconducting transmission lines, direct solar generated hydrogen fuel for fossil fuel replacement to transport waste to direct solar waste burning sites (Temp so high it even burns toxic vapour to useful pure carbon, the only output)

There is no technical challenge, only folks perception about how "Things are supposed to be".

In short, they wish to maintain enforced scarcity, which always enabled, and still enables slavery.

Are we not all wage slaves?

The banks could enable this tomorrow if they stood up and admitted our financial debt around the world is actually an energy deficit between us, all humanity, and our planet, and it can only be paid back down by solar.

But they want to keep enforcing scarcity, evidently.