Don't know why mild daily cycling of 10kw in V2H application would be anymore draining on battery than driving an additional 40miles.
eg: 100mi battery - drive 40miles and return home with 60% battery left -- plug in and V2H support another 10kw (40mi) leaving 20miles on the battery left. Charge overnight and repeat next day.
This is essentially what we do now with our Spark and Fiat. I presume that's what many Leaf owners do and don't suffer from battery degradation.
I think you meant kWh for the units, not "kw".
Well, you're putting on extra unnecessary cycles and heating the battery (or keeping it warm) by the charging and discharging vs. letting it cool.
Leaf's battery has no thermal management.
If you search thru TalyorSFGuy's posts, he had a 130 mile/day commute, charging fully on both ends. http://www.mynissanleaf.com/viewtopic.p ... 5&p=431911
has him down 5 bars by 141K miles in a mild climate ideal for the Leaf. I suspect many others in the PNW who have the same age of Leaf that didn't put on as many miles (and thus as many cycles) had less capacity loss.