@Debra300 While we often lose the power here for a few hours during the summer thunderstorms, I've actually never had the power go out when I had a guest in residence. This is in large part due to the fact that summer isn't tourist season here and I almost never get bookings during the rainy season-it's just too hot and humid. If tourists come here during the summer, they are looking for a place with AC, a pool, and close walking distance to town, which isn't what I have on offer.
So I don't say anything about it in my listing info, and if I do have guests when the power goes out, because I home-share, I just talk to guests about issues that might come up very casually, as if it's no big deal. That's how I talk to them about the insects that are endemic here and that's how I'd talk to them about the power if it went out.
But I think I have a fairly unique situation, from all the posts I read, in that I get guests who are generally seasoned travellers, have put up with far more difficult situations than anything they might experience at my place and simply aren't complaining, unadaptable people. They seem to view travelling as an adventure where you can't always predict what might happen.
A couple years ago I was having problems with the local water commission here- they weren't sending me water for a week at a time (crook in charge of the system, since fired, now I get water on a regular basis). I was having to go up on the roof to check my water tank to make sure if i did a load of wash, that there would still be enough water to shower and flush the toilet. I had a guest here and checked the tank one morning to find that it was almost empty. I can call a water delivery guy to fill my tanks, but it's not only an expense, it's a hassle to drag their huge heavy hose up to the roof. My neighbors, who are also my friends and are on an endless well, had told me if I ever needed water, to just hook up to their outside tap. That sounds easier than it is, as I have to attach 3 long heavy hoses together and drag them out across the property across from me , to fill my cistern.
So I told my guest, who was a really cool gal, to be a bit conservative with water for a few hours while I went through this routine. She asked if she could help, so we did it together and it took half the time it normally does.