[Sn1F3rt]

As per my knowledge the only way is to use alternate like solar panel sources and store it in dry batteries.

The EESI (environmental and Energy Study Institute) also release an article in 2019 on it. i share link here for detail study .

EESI

Now many of 3rd world countries now also step forward to reserve energy by using multiple sources like solar grid stations and from air. but i still not hear about storage of AC (alternate current) electricity storage plan. DC (direct Current) electricity storage is possible with different kind of batteries.

AC is what actually reaches your home as commercial electricity, DC is what is provided by these cells and batteries thereby much easier to store.

What you say about renewable sources of energy is appreciable. Though it has its pros and cons. With solar energy it's possible to store chunks of energy at once.

However the initial setup is very expensive. And I mean "very". Saying it's cheaper in the long run doesn't suffice if you don't have the money to invest at the beginning. So yeah, the bigger UPSes (inverters as they are called) still remain the most viable option.