Have you tried using the automatic backup feature? If you haven't, it can be found in Menu -> Settings.
If it is not already turned on, turn it on. If internet stability is a problem, change the backup location from Cloud to either Local browser or Download copy. That way the saving process will not depend on an internet connection.
Choosing Local browser will store the backups in your local browser memory, Download copy will download the backups to your system's download folder. Try them out and see which one works best for you.
The default auto save time of 10 minutes can be changed if needed.
As for the power, there is nothing to do about that from the software side. If the electricity is cut while making a backup, there is no way of knowing what the end result will be. Regular backups should cover for that though.