Well battery operated stuff may be fine for a short duration I certainly would not rely on them even for that time frame. Since there is absolutely no way anyone can tell how long power will be off, it wold be kind of hard to stock up on batteries, for say 12 hours use, and have power out for 24.........or not worry as yuor power is usually only out for 15 minutes, only to find oout this time its gonna be 2 days before its restored........There really is only one correct answer, and thats a generator.......You can find gen sets that do not cost an arm and a leg and run for 10- 12 hours on a tank of gas that are no bigger than a suitcase and will power everything on an aquarium, and even provide you with some lights as well......and its no more expensive than most aquarium related items...After hurricanes here all generators sets are sold out, and usually it takes a onth or two after the storm until they start reappearing in stores again.....however the first edition of the newspaper usually has tons of them for sale when the first edition of the paper comes out after power is restored, and all for a fraction of what they normally would sell for.....and most were relatively used very little.......Look around for a good small new or used gen set, and you won;t regret it when the need for power occurs.....We had two, now we have 3 gen sets. One will start automatically within 15 minutes of power outage and it runs of LPG/gasoline........but its hooked up for LPG to a 100# LP tank and we also have additonal LP tanks......This set powers the entire house so we can get on with life like nothing has ever happeneded in relation to power outages.........The other gen sets are a 8,000 watt which will power a good portion of the house if need be, incase the main gen set screws up.......may sound like overkill, but when you only paid $425 for a like new Honda powered gen of 8000 continuous rated watts, it was hard to pass up. The other is a 2500 watt honda gen set we picked up back in the 90's after a hurricane came through for 100 bucks that was only used about 10 hours then. Since then its probably gotten tons of hours on it, as its a very handy item. and was a backup for a few years until we got the large 20,000 watt gen set. Batteries just does not cut it, nor does the invertors sold for vehicles that allow you to run 115 VAC items......