And a knowledgeable reader, Eric Krieg, sends this link to a paper on high-phase power. Eric says
Basically, you can pump more juice through a 6 phase power transmission line corridor than you can through a 3 phase one. In a world where you can’t build new power corridors, it’s a pretty slick solution.
To my knowledge, New York State Electric and Gas is the only power company in the country to use this technlogy, although you can see from the references that the idea is not new.