Chicago Tribune: There’s a great scene near the end of the first “Back to the Future” movie. The mad scientist, Emmett “Doc” Brown, has just returned from his first trip to the future. He screeches into the driveway, pops the hood of the DeLorean time machine and unveils a small, Cuisinart-like device labeled “Mr. Fusion.” Instead of the earlier fuel requirement—plutonium (a lot more than $4 a gallon)—some banana peels and the dregs of a beer can are sufficient. When people ponder the …