OR in rural locations you could get a diesel, propane or gasoline generator and a really big tank for the fuel.
Almost everyone here in NH has a back up generator now. They are hard wired into your main panel through either a Gentran switchbox or a whole panel disconnect.
I have the first kind. It powers ten 15 amp circuits. Two or those power my well pump.
I have a Honda gasoline generator. My house is 50 years old.
The issue with gasoline is that IF its a big enough power outage sometimes the gas stations do not have power.
Most newer rural houses have propane heat. So, they also have a propane backup generator. Then they usually have a big underground tank. That you can run your house for a couple weeks.
Natural gas is typically not available unless you are in the cities or really large towns. I am in neither.
I am also in NH and have a backup generator for critical circuits, but I am researching a scalable, off-grid PV system for our home.
Starting with feeding our garden, chicken and duck house and our sunroom. Later on, expand to critical circuits like well pump, furnace, freezer and refrigerator and selected lighting.
We had a company drop out of the blue a year ago and tried to scam us with a grid tied monster way out of our price range and no battery backup. You have to watch out for these scam artists.