In my own experience here in Portugal were the whole country (well, the whole Iberian Peninsula) was hit by a 24h electrical brownout and then a few months later the place were I was living in was hit by a big freak storm effect that damage power-lines, trees, lots of roofs and so on, so we got another 4 days or so without power, and in my experience beyond the obvious (some canned food, some dry food) it’s good to have a couple more things:
First and foremost you want water. Not just drinking water but also water to flush your toilet once in a while. In my case, both times the power went down for long the water supply also went down. I live in a city so there was still water in the pipes for some hours, so as soon as I noticed the power was out I just filled some big containers with water using whatever water was still dribbling out and that was enough so that I didn’t need to leave the worst stuff in the toiled (if you get my drift). Also have some bottled water for drinking stored somewhere, at least 5l per-person.
You want some actual cash at home. In the situation I went through, even though power was out some shops were still trying to sell what they could (of course, because there was no power, they were doing the maths by hand and couldn’t take card payment as payment machines need power and an actually working telephone network to work none of which was available in a nationwide brownout) and as I had actual cash I could go to one and buy some extra canned and dry food just in case. Even if you forgot something in your preparation (like some people who didn’t even have bottled water at home), having some cash means you might be able to actually buy those things.
Keep in mind your fridge is not going to work if there’s no power. I actually started preparing and consuming the stuff in the fridge first, then the stuff in the freezer. If you’re like me and tend to go out and buy most of the food for the week once a week and always some have extra food in the freezer, you’re going to have at least some days of food from trying to empty the fridge and freezer before it spoils, before you switch to canned and dry food. In my specific case, but day 3 the freezer had defrosted (even though I avoid opening it) so actually the food that was in the fridge and freezer was enough even for the longer period without power (since it wasn’t peak Summer so if you cook some food one day it’s still ok the next day), though some food spoiled.
I was lucky that I have gas from the gas network and I had gas for cooking the whole time during both events. If you have electric cooking only, you’ll need some backup for it, maybe a basic camping stove and a small gas bottle for it (both are pretty cheap).
Have flashlights, and possibly candles for illuminations. This shouldn’t need to be said, but sometimes you only notice it when you need it.
A nice to have is a wind-up or battery powered radio. There’s no power, you can’t turn your TV on to check the news, and the mobile network will last about as long as the backup batteries of the mobile towers last (a few hours) and then your phone will have no Internet. By that point the easiest way to be informed about what’s going on is by listening to the news on the radio. I mean, you can talk to other people on the street, but in my experience I with a radio was much more well informed than most of them.
Talking about mobile phones, it’s a good idea to get a small charger powerbank and keep it topped up so that your portable devices actually keep on working. Even with mobile network, a smartphone or a tablet can still provide entertainment. After the first 1 day brownout here I actually went and got one of those and it was useful later when we had several days without power, which being localized and the product of a freak storm wrecking a lot of the local power network meant we actually had mobile network after a while but it took some days beyond that for power to be restored to most houses (and I’m inside the city limits - people further out spent longer without power).
This stuff is for a just pretty basic kind of situation that leads to being without power for up to a week (and by extension no water since the pumps of the water company aren’t working when there’s no power).
I actually have more layers to my emergency preparedness and could keep going for at least a month, but at that point we’re talking about things like freeze dried food or bagged army rations (a can of freeze dried food has a much longer good-until period than bagged food, and whilst it does need water and some way to warm it up, you can just buy a couple of cans per person just in case you ever need it, store them in a box somewhere and not worry about it for up to 25 years officially - non-officially they apparently last even longer - whilst the army rats last maybe 4 years so if you’re seriously about being prepared that way you need to buy new ones often as older ones expire), some means of water purification, like tablets, and some kind way of sourcing power (for example, a solar-charged power station) if you want at least your portable digital devices to keep working for entertainment.
In my own experience here in Portugal were the whole country (well, the whole Iberian Peninsula) was hit by a 24h electrical brownout and then a few months later the place were I was living in was hit by a big freak storm effect that damage power-lines, trees, lots of roofs and so on, so we got another 4 days or so without power, and in my experience beyond the obvious (some canned food, some dry food) it’s good to have a couple more things:
This stuff is for a just pretty basic kind of situation that leads to being without power for up to a week (and by extension no water since the pumps of the water company aren’t working when there’s no power).
I actually have more layers to my emergency preparedness and could keep going for at least a month, but at that point we’re talking about things like freeze dried food or bagged army rations (a can of freeze dried food has a much longer good-until period than bagged food, and whilst it does need water and some way to warm it up, you can just buy a couple of cans per person just in case you ever need it, store them in a box somewhere and not worry about it for up to 25 years officially - non-officially they apparently last even longer - whilst the army rats last maybe 4 years so if you’re seriously about being prepared that way you need to buy new ones often as older ones expire), some means of water purification, like tablets, and some kind way of sourcing power (for example, a solar-charged power station) if you want at least your portable digital devices to keep working for entertainment.