There are many ways to get power at low voltage (240/415 volts)
Either by use of a generator or solar with batteries or both.
These systems can be incorporated into an on-grid system to supply you with power if the grid fails or your only source power away from the grid.
We use and recommend Selectronic Inverters to supply power which uses Solar panels and Batteries with the use of a Generator so you will never need to go onto the Grid again, this can also be used for a backup system to back up the Grid. With the advent of the new generation of Lithium Batteries, it is becoming more cost effective as the prices are slowly coming down for this technology.
These systems have been used in House boats for a long time (especially hire boats) and the amount of power available is better than in some Homes. (depending on the system used)
I urge caution when buying these systems as some are being installed that do not do the job properly (not sized correctly) and being installed by unlicensed, so called “Electricians” – always ask for a Certificate of Compliance.