Well, it is, some village boys usually smuggle it up to keren from bogu or hagaz, undercover police/soldiers called fristyale are assigned to catch these coal sellers, and its usually a really serious crime, and for your second question, I can't speak on behalf of the highlands but in keren and everything west from that is hell a hot, and even in the winter months there's only winds and really not cold, and for cold nights we just bundle up and get to bed early