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It might be better to say that home PV and EV and battery storage go hand-in-hand (since that allows you to dump your surplus battery into your car at night), which appears to be Tesla's strategy. It would help if the battery storage were big enough to fully recharge an EV, but that's not strictly necessary unless you do a lot of driving.

Solar panels on cars are another option. I used to think that was a bad idea, considering that an electric vehicle uses vastly more power than solar panels could ever hope to generate. Then I thought about my own driving patterns; On a typical work day, I drive about three miles to work, park in the sun for 8 hours, and then drive three miles home. With an electric vehicle and a solar panel on the roof, I might not even have to plug it in except on long trips. Even if that wasn't true, if a solar panel could save me, say, 10 full charges per year, it's probably worth a little extra weight and cost.

I ran calculations recently on solar panels on electric cars. Taking Tesla's numbers, I figure it about .3 kwh per mile. A car is 5 feet wide, there are about 5 feet on the hood, 3 feet on the roof, and 2 feet on the trunk. So 50 sq feet, at 10 watts per sq foot, is 500 watts total. So 4 kwh per 8 hours, gives you 13 miles range. Or more likely, about 10 miles, once you count charging efficiencies.

It does if you think at grid level rather than building level.

What if you have a battery in the house?

Not a huge amount of people commute >150mi