“ you don't need to push, you pull. it's called a vacuum. (read full comment) ” 

Posted on May 20, 2011 at 10:18 AM EDT

+ 1 more comment posted in this discussion

“ you are assuming technology doesn't improve. bad assumption. (read full comment) ” 

Posted on May 20, 2011 at 9:14 AM EDT

“ sounds good but For 3rd world rooftops, you gotta be kidding? Thin Film Solar and a battery should be enough to power some lights and maybe a... (read full comment) ” 

Posted on April 19, 2011 at 1:00 PM EDT