We live in an outlying area where we lose power frequently from trees knocking lines down. We have been using a generator for many years for these occasions. Even an entire bank of golf cart batteries doesn't store the amount of energy contained in a few gallons of gas.
And if you are using a gasoline powered generator even the most efficient models go through a lot of fuel. We generally went through 10 gallons a day, and sometimes more. Fortunately, we have natural gas and were able to convert our generator to use that. This cut our fuel expenses to 1/3rd of what they were. Which still means that our electricity costs around 3 times what it normally does.
If you live out in the stocks where there is no natural gas, your best option would likely be to get a big propane tank and run your generator on that. It would cost multiple times what natural gas costs, but around here a lot of times the nearby gas stations lose their power also and can't fill up your containers, which can mean a long drive.
What make/model of generator do you use?