Good questions. IMO it’s all a numbers game and there are lots of unknowns. OTOH, once we’re transitioned to all electric, even having only 1% of cars plugged in and able to supply 10 kwhs at any given time could provide a lot of backup. For example in CA, 1% of passenger vehicles is around 140,000 units and that could cover a 1.4 GW power plant outage for an hour. If the number of cars at the ready was more like 10%, that’d be enough reserve power to run 1/3 of the CA grid for an hour. So depending on how the math works out, it could be significant.

That said, it might turn out that fixed home batteries end up providing the grid with all the reserve power it needs for emergencies and there’s no value in v2g. I really could see it going either way.

I think the most likely outcome is that a smallish percent of EVs end up with v2g as a side-effect of having v2h, which people pay for as an option for home backup. In my area in NH, higher income folks in rural areas regularly pay $10k for a backup generator and v2h could be an acceptable substitute for a generator for many. Automatic home generators are a pain because they run for a test cycle each week (noisy) and also they cost a couple hundred a year to maintain. Plus you need a gas hookup or a propane tank, which adds another ongoing cost/headache.

Yeah. As best as I can tell, current V2G designs aren’t being considered for routine daily discharge, but more for grid emergencies and grid stability.

Tesla’s home battery VPPs in Texas and CA are only discharging two or three times a month or so. They discharge when something funky is going on with the grid and real-time power prices jump up to $5 or $10 per kwh. That lets them pay powerwall owners $2 per kwh for discharging. That’s more than enough to compensate for battery wear and customers can control minimum state of charge to ensure they still have enough power to get to work the next day.

Having a few dozen gigawatts of at-the-ready emergency power on the grid can considerably reduce the cost of providing a stable grid and can generously compensate battery owners while at the same time reducing electricity rates.