@Pete69 I live on the Oregon Coast and had my first power outage with a guest here due to fierce winds. I chose to offer a full refund to my guests, even though they did not ask for one. I did this because even though the power was out only a short time, there were inconveniences caused to the gal that had booked that interfered with what had been a long-awaited, belated Valentine Day's weekend for her and her partner. One thing after another was going wrong electrically prior to the power going all the way out, including the hot tub going whacky. It was a real pain for her, and for me as the host as I tried in vain to figure out what might be going on.
Looking back, if I had not been so fearful of the dreaded 'bad review', I might not have offered a full refund. Even Airbnb Customer Support said I went way beyond anything they would ever expect. But it was just a gut feeling that this guest would have a better all-around experience with a full (not partial) refund to console her, and I do think it was worth taking the financial hit. It is the only time I have ever offered, or ever had, to refund. She did leave me a 'good' review - all 5 stars EXCEPT in the most important category, 'Overall' - Not because of me or the Cottage, but because of the weather. That one hurt a bit, I must admit. So just know that you can't necessarily 'buy' a five star overall review by giving a guest a refund.
These days I don't fear losing my Super Host status as much as I used to, and so I may have offered instead a partial refund or a 'treat' of some kind, as @Sandra126 mentioned, above. But that's how I handled it the one time a power outage happened to me while hosting.