I know a peninsula at least 12" x 24" requires one outlet. We won't have a raised area along one side with a breakfast bar like lots of people do, so there isn't a small backsplash to put one in.
I've never heard of anyone contemplating putting it in the wall abutting the end of the peninsula, just above the countertop like it would be above any other countertop. (It's not an "island" so it's anchored to a wall at one end). Why couldn't I do this instead of putting it below the countertop inside the peninsula itself?