Progress
This could be a very significant innovation. Where I live in the UK several new housing estates have gone up recently. Not one house has been built with solar panels on the roof and it's so frustrating. They're way too expensive and disruptive to retro fit, particularly for someone who's just moved in. If panels become cheap and available enough I hope they'll be compulsory on new builds in the UK. Proportionally they'd add virtually nothing to the cost of a new home. We've really got to start thinking about this stuff now.