They could have a V6 of V8They have already said it will support bidirectional charging which is what this means. Of course it's light on details yet. It will have to also work in grid independent mode to be an emergency generator not just V2G, with a proper interface charger at a relatively high amperage capacity with supporting wiring.
A 2.0 L gas engine would make a very powerful no compromises generator, easily 60 or more amps.
They could have like the RamCharger is doing, but they didn't.They could have a V6 of V8