L1/L2/L3 caches - expensive, small, but fast.
RAM - mid tier, still fast, bigger than cache, less expensive than cache, but limited in capacity compared to disk/flash based storage.
SSDs…
Disks….
You get the point.
Would it be the same with the grid?
Several power sources - nuclear, solar, wind, hydro, hopefully not coal and gas.
Banks of Lithium batteries acting as first level(efficient and immediate but limited capacity storage).
Whatever excess is directed to longer term, non immediate storage - pump up water to generate power later, molten salt, air compression etc.
Even more left? - spin up production of time insensitive materials that would be used anyway later - sea water desalination plants, green hydrogen generation, sewage treatment etc.
At large scale such tiered ecosystems would be very cool and super useful.