I do not have a backup generator, and had a 3 hour power outage with the eggs about 2-3 weeks in. The temp dropped around 7 degrees in the incubator with in this time. Some of the babies in one of the clutches came out with deformities. All of the other clutches hatched out just fine.
I am planning on getting some sort of back up. I was thinking a UPS, but am not sure which one to get.
Good luck with your clutch.