I read an article about a couple in New Hampshire whose reception hall lost power due to an ice storm. They went ahead with the original plan but ran extension cords from a neighboring business so they could have music and a lighted Christmas tree. The rest of the light was provided by candles.
It reminded me of a wedding I went to a few years ago in Louisiana. The power went out unexpectedly in the middle of the reception. But rather than ruining the event, the outage actually made the wedding more meaningful and memorable. The bride's students (she was a middle school teacher) started singing and dancing without music. It was such a surprising and heart-warming tribute to the married couple.
It's so easy to worry about whether everything will go just right. In fact, I sometimes had nightmares about my wedding during the planning stages. However, the imperfections might just make it all the more perfect.