I can give a real datapoint: Family of 4 in TX, suburban neighborhood, and we drive a ton of mileage (~25-30K/year) running kids around town and the occasional

I can give a real datapoint: Family of 4 in TX, suburban neighborhood, and we drive a ton of mileage (~25-30K/year) running kids around town and the occasional roadtrips. ~2 years ago, we financed solar panels on the roof, and around the same time, bought a brand new Tesla Model Y. We came from a slightly-larger gas SUV before that. I also switched electricity plans, and opted for one with free nights (9p-9a) and a high rate during the day, which doesn't buy back any power from my solar, because the math works out better that way. So basically the car recharges for free overnight, and the solar helps offset a decent chunk of the daytime usage. When I net /everything/ out (electric bill changes, solar monthly bill, car payment swap, fuel, and maintenance costs), all total on average I'm coming out ~$700/month ahead from making these changes.