Broadband over power lines has been tested in many markets. There are several systems.
MOST of those systems.. Suck big time, they both cause major interference to licensed radio services and are subject to interference by the same.
ONE system (I won't name it because I'm not sure and I'd rather not name it than be wrong on this) it seems, works well without this problem.
But serveral BBoPL projects simply vanished,, no takers for the service.
What can I say
Same is true of the 'Home' type modules that let you use yoru house wiring instead of pulling Cat 5.. Some of them are kind of bad,, Though there is at least one that is OK and plays well with other radios.. They are radios by the way. Even if it's "over power lines" not over the air.