The solution for this is to buy a generator. Hand started 1 kW ones go for ~130€ these days (https://toom.de/p/inverter-strom-generator-sg-1200/1501059), plus enough cable from <somewhere outdoor> to <location of fridge>. That's enough for 24/7 running the fridge and any other important appliances (think a TV/radio and a cellphone charger to have access to some form of information/communication).
Don't even need to keep a jerrycan around and risk the fuel go stale if you know how to siphon fuel from your car in an emergency (for a widespread outage, it is not guaranteed that gas stations are operational). Only requirement is to check oil level and start them up and run for at least half an hour once a quarter (you might get away with half a year).
PSA: Do not, never ever, even dream about putting that generator indoors unless you have a certified chimney sweep (or whatever your regional equivalent is) certify the safety of the exhaust system. And even if you do (or have any other sort of fuel furnace in the house), get at least a CO warner at the most bottom place of your house!
Don't even need to keep a jerrycan around and risk the fuel go stale if you know how to siphon fuel from your car in an emergency (for a widespread outage, it is not guaranteed that gas stations are operational). Only requirement is to check oil level and start them up and run for at least half an hour once a quarter (you might get away with half a year).
PSA: Do not, never ever, even dream about putting that generator indoors unless you have a certified chimney sweep (or whatever your regional equivalent is) certify the safety of the exhaust system. And even if you do (or have any other sort of fuel furnace in the house), get at least a CO warner at the most bottom place of your house!