The OP said cost effective, not pie-in-the-sky.
Even if you took out the battery packs and sold them separately, the cost would exceed 10 years worth of electricity supply.
>Owners can be heavily compensated for pushing energy back into the grid.
You're asking people who cannot afford the expensive technology to subsidise those who can. This is the exact reverse logic of most progressive taxation regimes.
>The question is; would 5% of the driving population buy a $50k car if they no longer had to pay for fuel or battery packs? Financially that would probably put it closer to a BMW.
So you want to subsidise the purchase of expensive cars to the point where it is financially a good deal. This magic money no doubt comes from other taxpayers.
And for what end? Just so you can have some type of boutique distributed power generation system?
>What's needed is the will to make it happen.
No, what's needed it pots of other peoples money.
I've spent the best part of 5 years trying to hose down the jetsons fantasies of people pushing ridiculous schemes like this as not only unworkable, but inequitable for forcing up a basic cost input of life - energy - for effectively vanity purposes of a small subset of the population. I usually cop a pile of flamebait and downvotes each time, but I do so because there seems to be a mass delusion going on, and this has become one of those things you can't say.