In modeling whether this makes sense, I looked at my annual electricity bill, which comes in at about $1,800/year. That's not enough savings opportunity to justify a ~$70,000 roof+batteries.
However, when I add 2 electric cars, the savings nearly triple [0]. Instead of buying gasoline, I'll be paying for electricity.
At $5,400/year, spending $70,000 starts to make some sense.
On the other hand, if I put up ugly panels and still use the Tesla batteries, aren't I going to save a lot more?
[0] 24,000 miles/year, 225 miles @ $10 per charge, vs. 25 mpg @$3/gal
EDIT: Corrected KWh charge... $10 is cost for one charge.
What's your goal though? If it's just to save money then it makes more sense to drive a beater gasoline car.
If the goal is to help the environment, it's probably still better to buy a beater gas car and buy carbon credits with the difference. Also there are tons of other things you can do like downsizing, eating less meat, biking to work, etc.
Keep in mind, a battery array isn't something patented by Tesla, you could easily (safety in mind!) create a "powerwall" yourself; or use someone else's.
However, when I add 2 electric cars, the savings nearly triple [0]. Instead of buying gasoline, I'll be paying for electricity.
At $5,400/year, spending $70,000 starts to make some sense.
On the other hand, if I put up ugly panels and still use the Tesla batteries, aren't I going to save a lot more?
[0] 24,000 miles/year, 225 miles @ $10 per charge, vs. 25 mpg @$3/gal
EDIT: Corrected KWh charge... $10 is cost for one charge.