The "additional complexity and uncertainty" of V2G is the basis for Tesla Energy and wall mounted batteries. Why shouldn't I be able to use my huge car battery for this? If I could, maybe Tesla would get some love from PGE, or BGE, since I'm in Maryland. As near as I can tell, the problem is with free supercharging. I'd favor charging local rates at superchargers, for this if no other reason, but it also might help get other companies to build superchargers.