F-150 Lightning called it right: EV’s should ship with grid-tie inverting.
The CAISO shows that their current power generation capacity is about 53000 MW.
A Tesla model 3 has 60kWh of capacity. A million of those would allow generating 60000 MW for an hour if they would be discharged from full to empty during the span of that hour.
In practice, they wouldn't be able to be discharged that quickly and there would be losses due to going from DC to AC, but it's interesting to think that the total deployed battery capacity of EVs could have a significant impact on the need for peaker plants in the upcoming years.
You'd use an app to control how much power you allow to be taken and when. Mainly grids have peaks in the early evening and excess wind power during the night and excess solar power during the day. It's as much as being able to absorb that excess power than it is about providing power during peak hours.
During the daytime, solar power is plentiful, but not during the evening. However, during the evening, there is demand from residential customers so that they can cook, watch TV, use their computers, and whatever else people do in the evening that uses electricity.
Because there needs to be as much energy supply as there is demand, peaker plants (coal or gas typically) run during the evening to compensate for the fact that solar generation isn't available in the evening. There is less demand for power overnight though, since most people are sleeping.
As such, what would make sense would be that people would recharge their cars during daytime, drive back home, connect their cars to the grid and have them contribute some percentage of their battery to lower the need for peaker plants in the evening, then charge to full overnight.
Those batteries have long lives in the car and then typically a second life in storage solutions. Some cars now come with vehicle to grid technology and when they are plugged in, they could be used to provide power to the home, or the grid.
So we have a fleet of car batteries that is currently growing by the hundreds of gwh per year and soon twh per year that can be plugged into the grid. Even just using a tiny amount of that represents an enormous amount of power.
That's a huge buffer to dump excess power in during the day (from e.g. solar panels) and withdraw from during peak hours. The current Tesla virtual power plant is tiny in comparison. If you then consider that batteries have a fixed number of cycle times (around 1500 or so), you basically get to pwh scale in terms of amounts of energy that flow through that buffer every year. A lot of that power is cheap renewable power. Just with car batteries. Other storage solutions are available. The world currently produces a bit over 25 pwh per year currently.
Degradation of lithium batteries is also not constant. It depends on several factors such as C rate, heat, and voltage. All of these factors would be far less during load sharing than just driving your car.
And keep in mind most people wouldn’t want to share their entire batteries. They would want to save most for themselves. If they only offered 10% of their capacity for load sharing, then the shared usage would be far less than a full cycle.