Hydrogen still takes a butt load of energy to produce. http://en.wikipedia.org/wiki/Hydrogen_production I really don't think we are there yet with hydrogen production. Also, remember geo metros (3 cylinder). they get like 60 mpg. Scooters get 80? Would solar energy to fuel a car even work? http://en.wikipedia.org/wiki/Solar_vehicle I think the limitation there is with batteries. Also, check out how germany is getting solar energy, spending money to subsidize solar panels. http://www.washingtonpost.com/wp-dyn/content/article/2007/05/04/AR200705...