For Japan, many pumped storages have been built to store energy generated by nuclear plant mainly at night. Now few nuclear plants running but many PVs are deployed, so it stores energy at noon. It's reversed but anyway it's useful!

Storage is always useful. At issue is where money is better spent, right now.

For nuclear era, it was easier to pay cost for storage because same operator built both nuclear plant and pumped storage. Even if operator isn't same, there are only few nuclear operator in the grid so easier to talk. For PV (or say electricity deregulation) era, it will be a bit difficult since PVs are deployed by small operators or individuals. Great market mechanism or govt regulation is needed.

California quietly added 3GW of batteries in the last three years to shift mid day solar to the evening. I think part of the quietly bit is locating them at mothballed natural gas peaking plants. Advantage the power infrastructure is there and no use change permits needed.

Before that, they attached pumps and ponds at the bottom of penstocks leading to reservoirs in the Sierra Nevada mountains that were built decades ago.