What sort of benefit could you get by "friending" your utility company? How bizarre. Maybe they want to deliver policy changes or energy saving tips more easily? That's the sort of thing I don't mind reading through snail-mail. (Email is too ephemeral, and FB... well, that's mostly noise).
Companies that put up facebook pages are just doing it because its easy and there is no cost associated with it. Nobody is depending on it and nobody will care much about it when the next big platform comes along.