A world where individuals are incentivized to use some wasted space to place low maintenance automated trading batteries to make a little money on the side seems like it'd be an interesting solution to the renewable energy storage problem. Put a few units in otherwise useless locations like on roofs or in between highways and make some cash, sounds like a decent investment.

Would there be any expected problems in doing such distributed power storage on a very large scale around the grid that you'd have to account for? Perhaps issues with synchronization, power flow or the possibility of large scale drops in avaialble stored power at times?