Utility Dive, Oct. 31, 2016, by Gavin Bade.
http://www.utilitydive.com/news/5-unanswered-questions-after-teslas-big-solar-roof-and-battery-announcemen/429393/

".... Last Friday, CEO Elon Musk unveiled a slate of integrated solar roof and battery storage offerings that mimic the design of traditional roof shingles and eliminate the external mounted panel designDetails about the panel efficiency, battery life and overall cost were left out of Musk’s presentation, leaving a number of open questions about the sleek new Tesla offering and its potential impacts on the market."