For a 10g tank a couple computer UPS battery backups should work for you.
In the event of a long power outage you'll want to reduce your photoperiod, so you're really only gonna run your filter pumps, and maybe a powerhead.
If it's a really long power outage, you can get inverters so that you can charge the UPS off your car battery.
For my systems I've got a small 1200w generator. It's a no-name cheap one. I think I spent about $125 on it. I may look into getting another one in another year or so. I'll probably go with a Honda quiet one 2000w model.
B
