I ran across this article (looking for the first test flight of an algae powered plane) on how a 15 yr old created their own home energy plant. IF this kind of thing worked and was demo'd in an entertaining way, could power an attraction. Thought provoking stuff. As an Imagineer, you usually start with stuff like this as research and look for what may capture the guest's imagination.
http://cleantechnica.com/2009/06/09/15-year-old-invents-complete-algae-energy-system/
http://www.greenaironline.com/news.php?viewStory=206
When the public sees that algae can be grown to fly them to Hawaii (still preliminary) or power their home from waste while lowering their own cost of living, then people go home from WDW with a renewed sense that Disney really can make dreams come true because they showed them.. As much as Fantasyland delivers on it's promise when you ride IASW or Peter Pan, Tomorrowland or (EPCOT) has to deliver on it's promise too. And it's not just a demo of something cool, it's emotional and life changing. The issue has been in the past that technology changes too fast so you cannot be current. Walt knew that, but set the bar in 1967 so far out there it could last, as he gave the guest a long term goal of EPCOT, a city of the future they wanted to actually build.
My fave quote about all this stuff came from one of the Disney fellows, a group of science consultants we had on board and truly great thinkers. Alan Kay (credited with inventing the personal computer and the mouse) once said "the best way to predict the future is to invent it". (He later argued that maybe you should switch invent for prevent)
Gotta love that! If you want to experience the kind of conversation you'd have at WDI with a man like Alan (I'd just listen), read this lecture on computing. It's eye opening. Have some fun and open your heads!
http://www.windley.com/archives/2006/02/alan_kay_is_com.shtml