Well, you were explicitly asking about that scenario so that's why I addressed it. > 1) Charging, driving, and charging is never going to be economically compe

Well, you were explicitly asking about that scenario so that's why I addressed it. > 1) Charging, driving, and charging is never going to be economically competitive with transferring power through transmission lines. I can charge at 5p/kWh during the night but during the day would be buying at ~25p/kWh as a regular customer at home - buying from a charger on the road would be more expensive (if nothing else, the VAT situation is different I think). Is it not reasonable to think that it may be more economic to transfer power between two cars near each other than across the country? That's what would be happening if I'm putting back on the grid while someone else is charging their car somewhere. > . Then you have to cover expenses: wear and tear on your $20,000 battery, on the rest of your car, opportunity cost of sitting there giving away power, and most importantly the planning and risk involved in driving afterwards with less in the tank. I think you're picturing explicitly driving to a car park to sell excess power. That's not what I'm talking about. I'm saying that going to the shops/work and plugging in my car, it may easily make sense for my car to sell some of that electricity to someone else as I'm not going to need it today and can charge up at night cheaply. There's no wear & tear on my car, and no opportunity cost about sitting there. Wear & tear on the battery is identical to any other load shifting, home battery or car, so if it doesn't make sense to do in the car park it wouldn't make sense to do at any other time. > and most importantly the planning and risk involved in driving afterwards with less in the tank. That's what the commenter was talking about with some smarts on trip planning. Frankly for most people long trips are rare enough that a default "leave me with X in the tank unless told otherwise" would deal with almost everything.