From what I've heard electricity providers in Australia prevent you from doing what you want as far as batteries and storage are concerned.
Off grid means exactly that: totally off grid.
In the future I'd guess that providers will try and implement some kind of rules that prevent people that are off grid from getting away from paying the supply charges even though they are not hooked up to the grid. As the line goes by their property they have to pay up anyway.
The supply charge in Australia for electrcity is way too high. That goes for water, sewerage, and natural gas as well.
