R
ReddyLeaf
Guest
I want to agree with your post because it’s “mostly” right. However, all of this assumes that cycle losses are greater than calendar losses. That’s NOT always the case. For low mileage drivers, it’s the opposite and V2G-full would make perfect sense. For example, my 2011 Leaf with the original crappy battery has 8 of 12 bars at less than 60,000 mi. A high mileage driver in Seattle got 150,000 mi with the same amount of degradation in 4 years. So my battery could have been cycled without any additional degradation. If I could get a financial benefit from cycling, I would have. My commute was less than 10 mi RT. Given free solar during the work day (say in California where they actually curtail solar), and giving some back at night, maybe 10 KWh out of my 20 KWh), I would definitely get a financial benefit without additional loss of use. Now, I know this doesn’t necessarily work for higher mileage drivers, but it will make sense for some. V2G makes perfect sense for people buying 300 mi EVs, just because they’ve been told to worry about range anxiety, and only driving 50 mi/day. I think there are more people out there like this than you realize. I advocate and advise 100s of people about EVs and I’m constantly amazed by highly educated people who think they need 200+ mi range to drive 2 miles to the store (I’m in a small metropolitan area that’s less than 30 mi across). Again, your or my “normal” isn’t necessarily the same as others.The battery will almost always be used to its full cycling potential (barring the premature loss of the vehicle in an accident) - V2G or no V2G. No potential is being wasted. What strikes me as dumb is preemptively aging the battery pack, which will bare minimum require a battery replacement, and would usually cause a whole car to get thrown away years earlier than it otherwise wouldn't have been (since most people probably won't do a battery swap on an old car). What also strikes me as dumb is dedicating cycles of cells focused on energy density to a task that would be better suited to cycles of cells focused on longevity and cost.
Cell cycle lives are finite. You can't get around this. If you allocate a cycle to one thing (e.g. V2G) then you're not allocating it to something else (like driving). You make more cycles by making more cells. Do you want said more cells/cycles to be ones focused on longevity and cost, and installed where they'll do the most good, and always connected to the grid when the grid will need them? Or do you want said cells/cycles to be focused on energy density instead, and always in a car, which may or may not be connected to the grid at a location where they may or may not be needed?
A much better option is smart charging. Like V2G, but without actually outputting power. You tell the car how much of a charge you want and when you want it, and it decides - based on grid rates, reflecting grid needs - when to actually do said charging. Smart charging doesn't impose any extra cycles on your battery pack, but it keeps vehicles from charging (unless owner needs demand it) when the grid is stressed. It of course, like V2G, requires a smart grid which can transmit power needs and forecasts.
I will agree with your description of V2GH (half duplex). Unfortunately, utilities want to sell power, not buy it back. From a system wide perspective, V2GF does makes sense in some areas like CA with excess solar and high costs, but the utilities will fight it because it reduces their profits and ability to charge exorbitant prices during high demand hours 4-9pm). In all areas V2GH will make sense from a voltage regulation sense, but again the utilities don’t want to pay more for the reliability. Eventually, Tesla, Apple, Google, and other forward looking companies will apply to be utilities (I think Apple already did) and start applying these principles. Tesla will have a competitive edge with stationary and mobile sources of frequency regulation, load response, demand response, all tied together with AI and historical data. Perhaps not this year, but it’s coming.