ha, ha, solar power can not supply us with a fraction of the energy we need, so why would you ever store it?
Uhhhhmmmmm..... for what we call "night time". Why do we use batteries? How do you start your car? I've got stored power in this laptop as well as in my UPS units for when the grid goes down.. Some of my neighbors aren't even on the grid.
I think that we are already on the verge of major developments in solar. This is just one of them. The energy co-ops in Germany using many sources of energy, solar, biomass, wind, ect. is another.