alt Hacker NewsIf your home is isolated from the grid you don't have to worry about syncing your 50/60 Hz. A UPS during a blackout is an example. I experienced it myself.
I have no idea about the hurdles of keeping in sync many batteries in many homes connected together. This is not even something I thought about before the news of the blackout in Spain months ago.
Keeping in sync isn't as much of a problem as you might think, it simply requires that everything able to feed into the grid has to accept the grid as authoritative for syncing.
Relevant are some of Chris Boden's videos about bringing up a hydro power plant and his comment that you have to be in sync with the grid when you actually connect because the turbine WILL sync to the grid at connection and if it was incorrect before then there will be a lot of loud angry noises from the equipment. https://www.youtube.com/watch?v=xGQxSJmadm0