Sounds like interesting tech. But as another poster noted, to be useful it needs to be able to deliver the heat to homes, which requires a steam pipe system. Not necessarily a dealbreaker, but definitely a big up front cost that communities would need to consider.

Also, it makes sense that the battery basically just consumes electricity that would otherwise go to waste. But I think it could be an even better system if the sand were heated more directly by the sun for additional heat storage during winter.