We have a similar, but different situation here in Johannesburg. Load shedding (planned rolling power cuts) is often put in place because the utility doesn’t currently have enough generating capacity.
It’s common knowledge, usually lasts a couple of hours and impacts the whole city at different times.
We mention it in the listing and send an automated reminder to all guests the day before they arrive.
I think I once had a guest complain - as they had assumed the apartment block would have a generator, but it doesn’t - but most people just roll with it (excuse the pun😉)
Might be worth you trying a similar approach.