You can control how much is given to the grid, and say that e.g. it has to have 60%+ left at all times. There's no need to keep cars charged to 100% all the ti

You can control how much is given to the grid, and say that e.g. it has to have 60%+ left at all times. There's no need to keep cars charged to 100% all the time. They already have batteries that are overkill for daily commutes, and if you suddenly need to make a long trip, you can top it up in 20 minutes from a highway charger. BTW, on the Internet there's always some guy who just has to have a 500-mile daily commute while towing a boat, through a desert, in snow, uphill both ways. That's fine, they can opt out. Note that the charging connector isn't a dumb plug like a household appliance. It has a two-way communication protocol that negotiates all of the parameters.