With everything going on ranging from the various wild fires, to extreme heat in some regions, it can be HUGELY important to have a backup plan in case there are any rolling power outages in your area. Some of the following are either short term or long term solutions, that kind of have their own set of pros and cons.
- Battery Powered - A lot of equipment can be found in a battery powered form, such as small water fans (to circulate the water around) to even air pumps. These devices are really only limited to the number of batteries that you can carry on hand.
- Backup UPS - These are those devices you normally find with higher end electronics, or with computers. These are huge batteries that can power devices for a short period of time to a very long period of time dependent on the amount of wattage you require. Sadly, once they are out of battery usage there isn't a way to recharge them unless you have another way to feed them power specifically.
- Generators - This is a long term solution and normally is found in higher end setups (such as for saltwater tanks, or aquarium companies) that allow for you to power everything as long as you have enough fuel to keep them running.
As far as heaters, I have yet to find a heater that works and is battery powered. You may need to get a UPS, or try to find a better solution (dependent on your area, make a fire and use river rocks and heat them and then place them into your tank if its extremely cold outside - just make sure to watch the water temperature so it doesn't overheat or get way to hot fast).