Agree about the car batteries. If you think about the storage problem in a less abstract way, it's largely shifting demand from around noon when the sun is shi

Agree about the car batteries. If you think about the storage problem in a less abstract way, it's largely shifting demand from around noon when the sun is shining to about 7-8pm when people are active but solar is producing zero. For car battery storage to help with this, the car has to be plugged in while its owner is at work to soak up the noonday power, and then plugged in again at home to be discharged. By the time most people go to work in the morning, there isn't enough sun to charge the car yet, so they have to go to work without whatever power has been taken out of the battery at night, so the battery has to be bigger than is necessary for driving. This extra battery capacity in the car is much more expensive. It's not 100% available, because sometimes people won't plug in their car, and it has to be made more rugged to deal with driving on the road. You're also paying an energy cost to haul an energy storage system to and from the office every day. Overall, you'd do better by just using large scale fixed battery banks that can be optimized for energy storage. The only real reason to like vehicle based energy storage is that it takes the cost of energy storage off the books of renewable generation and hides it in transportation costs.