I'm going to be late for work due to a power outage
Is the outage only affecting you?
It's a total failure of the electrical company in the region.
It sounds like you did all you could, so I hope your workplace understands your circumstances and you don't get reprimanded. Have a nice day at work.
It's no big deal, everyone is welcome to be late and it is accepted.
It's good that you have an understanding and supportive work environment. I'm sure it's a lot less pressure and leads to higher productivity.