I'm an EV owner and homeowner and looked into V2X when planning my solar/residential battery system. On the home side, the hardware is largely there. The charg

I'm an EV owner and homeowner and looked into V2X when planning my solar/residential battery system. On the home side, the hardware is largely there. The charger I'm buying and many others support it - though many need a future software update. On the vehicle side though, it's very inconsistent; there are only a few vehicles that support it and even for those, what my installer told me is that the manufacturer warranties typically either void the warranty entirely if V2(G/H) is used or harshly limit the amount of energy that can be used. They're concerned that it will lead to excess wear on the battery, the main component of an EV. And I think I agree with them. With current battery technology, I don't think using EVs as a grid-scale storage system for renewables is viable. For grid-scale or residential storage, you want a battery that can be as heavy and physically large as it needs to be but it needs to deal with a lot of charge/discharge cycles. Your best option here right now is LiFePO. For the kind of EV people are generally willing to buy right now, you need to cram as much range into the car as you can, which means the battery needs to be as energy-dense as possible and charge/discharge cycles are less of a concern. That means LiPo. I think the most realistic use of EVs for grid-scale integration is what they're calling "virtual plant", where they're treated like a separate source of energy that the grid can tap into in exceptional situations.