- EV battery recharge resource is not infinite. Spending it on grid stabilization could be quite costly if you'll factor in cost of battery replacement. In the long run it could be cheaper to build mines for hydroelectric/compressed air storage.
- It will require huge capital investments. You have to equip every parking spot with inverters which can both charge EV and supply power from it to the grid and invest into upgrading grid to be smart enough to work in such conditions.
- What will happen on low-energy days? It's fine to drain most of power from hydroelectric storage or from stationary flow batteries, but you simply can not do it with EV. Imagine being told "sorry pal, you have to walk home today, power from your EV was used to stabilize the grid".
I would hope if we started selling power from EVs back to the grid, that owners would be able to set a reserve amount of charge, and only sell excess above that level. And presumably it would only make sense for owners who could charge when demand is less, and opportunistically sell back a portion if demand is unusual high.
- EV battery recharge resource is not infinite. Spending it on grid stabilization could be quite costly if you'll factor in cost of battery replacement. In the long run it could be cheaper to build mines for hydroelectric/compressed air storage.
- It will require huge capital investments. You have to equip every parking spot with inverters which can both charge EV and supply power from it to the grid and invest into upgrading grid to be smart enough to work in such conditions.
- What will happen on low-energy days? It's fine to drain most of power from hydroelectric storage or from stationary flow batteries, but you simply can not do it with EV. Imagine being told "sorry pal, you have to walk home today, power from your EV was used to stabilize the grid".