Yes, Nissan does vehicle to grid for fleets. In the LA area the US Army has a bunch of Leafs and the necessary infrastructure.
A bunch of companies make bidirectional chargers, including ABB in Europe and Nuvve here in my town. They are expensive, I saw a price of $4000 at the turn of the year. However, if I can arbitrate between my 4pm-10pm high peak rate of $0.53/kWh and the midnight to 6am night rate of $0.09/kWh, that will pay for itself eventually. And it would help stabilize the grid while I make money.
Ford has said the F-150 will support V2H with a pro grade Ford Wall Charger. They are apparently working on this in partnership with SunRun.
Apparently the EVSE has a CCS plug and supplies 240VAC to the car via J1772, and return direction flow over the CCS power pins at up to 9.6kW. Maybe to isolate the return path?
I recall reading something about VW exploring V2x stuff. In fact, this article states:
Volkswagen has announced all of its ID. branded cars will be V2G capable starting in 2022.
Certainly, adding cycles to an EV pack is in the back of auto makers minds. For most V2G implementations, the fluctuations are minimal, just enough to balance grid loads, and this would seem to have minimal impact on battery longevity. V2H might have more impact if users dip deep into the EV pack on a regular basis. For the occasional power outages, maybe not as big of a concern.
Tesla seems to favor owners buy dedicated storage for homes rather than use their EV batteries for home backup power. That is likely to be aimed at reducing product cannibalism.
I wonder if owners who participate in these kinds of uses of EV packs might face issues with warranty claims? The fact that Ford + Sunrun are working together on this suggests Ford will be aware of those who implement it, and may flag the warranty on these owners packs?
Then again, Ford and VW seem to purposely set aside a portion of the pack capacity, permitting only 90-95% of the raw capacity to be usable. Maybe that is to minimize stress and reduce the probability of warranty claims? Or maybe it is in anticipation of V2x implementations in the future?