I see it a little differently. What they seem to be after is the dollars that homeowners currently spend on both gasoline and electricity. They can wrap that up

I see it a little differently. What they seem to be after is the dollars that homeowners currently spend on both gasoline and electricity. They can wrap that up nicely if they can offer the batteries and shingles at a monthly cost that is at or below the gasoline spend. That's about $5,000 in gasoline (2 cars, 18,000 miles @, 22.5 mpg, $3 gal), plus $1,500 in electricity for the home (very round numbers) = $6,500 annually that is in play. In 10 years, it's feasible that middle class homeowners will have 1-2 electric cars. So if Tesla can offer self sufficiency in energy, which is really what their play is, for a cost that is similar or less than $6,500/year, they have a market. What it all turns on, which wasn't immediately obvious to me, is that the electric cars are appealing both in performance and style. If not, mass adoption languishes, and Tesla's $1.8 Billion ROI may languish as both the gigafactory and solar shingle manufacturing sit idle. It's somewhat heartening that Model 3 has such a great initial reception in the press. But what a gamble...