As the worlds power supply transitions from majority fossil...

As the worlds power supply transitions from majority fossil fuels to majority renewables V2G will be an essential component however it will strike consumer resistance if the power companies have full control. The individual customer will need to retain control of the amount and the price at which they are willing to sell power to the grid.

For example it is a sunny day and your EV battery is fully charged your array so you would be willing to sell power at say 15c/kWh or even just your standard FIT. The power company doesn't need power because everyone else's panels are pushing power into the grid so it doesn't buy any from you. Later on as the evening demand starts to kick in the power company does buy some power but when your EV drops to 90% SOC your asking price rises to 25c/kWh.

Other people are willing to sell their power for 20c/kWh so the power company stops drawing power from you however as the evening peak hits the network more power is drawn from your EV until its SOC reaches 80% when your selling price goes up to 35c/kWh. They only buy a couple of k/Wh before the evening peak passes but next morning before sunrise there is minimal wind and they buy more power until your EV SOC drops to 70%. Then your asking price rises to 45c and they stop buying power from you again because other people are willing to sell more cheaply.

Of course all the price thresholds would set by consumer controlled software and could be adjusted for predicted weather conditions and past power price cycles.