If there's a natural disaster cutting off electricity for days, trading bitcoin should be least of your worries really. Priorities man.
This made me chuckle, of course if there was no electricity you should be worrying already cause maybe there was an explosion, or any natural disasters and even war that causes your place to cut off the electricity, but if you think and you are sure that it's because of maintenance, I guess power generated supplies that can charge your gadgets to start trading will help you to ease the temporary inconvenience, better to save money now and buy some products like this.