There is a house North, I am sure you contacted, referred to as the windmill house (between Mata Chica and Xaman Ek). They have been on wind power for more than 10 years, but also have a BEL connection (I am not sure how they managed to do that).
Small systems usually come with battery back up. For bigger systems - depending on power demand - you need a back up generator because the wind is not constant and we have long periods with virtually no wind.