1. Hydrogen electrolysis. may well be good but there is money and interest already for that if it's a good enough invention in the field it will likely have some success it doesn't need the earth shot million.
2. The rent a battery service. I would maybe put this as a longer term start point say 4 to 5 years when hopefully solid state batteries become more viable allowing for more dynamic in battery rental. Right now it would just put a higher demand on limited lithium reserves although maybe some progress can be made now.
3. micro grids. oh I think this is definitely the winner in my view. micro grids could play an essential role in the future for much of the rural connectivity and ecologically levelling up mark a path towards things like new places to draw sustainable energy by widening the range on the grid plus many other benefits to connecting the rural communities up to the world cost effectively.