There are power outages in Norway too - though there are typically years between incidents, and years and years between incidents lasting a day instead of hours

There are power outages in Norway too - though there are typically years between incidents, and years and years between incidents lasting a day instead of hours (with the exception of certain avalanche-prone areas where this happens much more often than people would like). So my home has a backup system - as do most houses. And that's a wood heater. But my house is so well insulated that it takes a day even in the coldest of winter before I actually need to use it if this happens. Newer houses are also quite much better than mine in this respect.