Looks like a cool idea, although I'd need to see:
Economics, how much to install and how much power do they make.
Hail. After this year and having $6k damage to my wife's car after getting caught in a 90 second storm, downspouts renovated to have the "hammered metal" look and many folks roofs and vinyl siding destroyed I'd want to see some serious proof.
I'd say 50% of the houses on my street have had their roofs re-done in the past 4 months due to hail damage!
Winter. If it convert's all the sun to electricity you don't heat up your roof and melt off the snow....meaning you either have to clean after every storm of you'll have a big buildup. I'm a self confessed heights wimp, won't even do Christmas lights let alone get up on my second story roof