>What will change is the source of that fuel. It may be some kind of hydrogen-rich fuel (methane or ammonia) or it may be making the necessary hydrocarbons from

>What will change is the source of that fuel. It may be some kind of hydrogen-rich fuel (methane or ammonia) or it may be making the necessary hydrocarbons from the air and/or seawater. There isn't any such fuel. Hydrogen is dangerous and corrosive, ammonia is hygoroscopic, hydrazine is super-toxic, boranes destroy everything, and that's the end of the story. Synthesizing hydrocarbons is highly inefficient, ditto for biofuels. The range of hydrogen vehicles is not particularly impressive: http://en.wikipedia.org/wiki/Mazda_RX-8_Hydrogen_RE http://en.wikipedia.org/wiki/Mazda_RX-8_Hydrogen_RE http://en.wikipedia.org/wiki/Hydrogen_7 http://en.wikipedia.org/wiki/Hydrogen_7 http://en.wikipedia.org/wiki/Peugeot_Quark http://en.wikipedia.org/wiki/Peugeot_Quark If you're willing to spend more, you break even with electric cars: http://en.wikipedia.org/wiki/Honda_FCX_Clarity#Specifications http://en.wikipedia.org/wiki/Honda_FCX_Clarity#Specification... Electricity works because it's cheap, and only getting cheaper: powering my house already costs me less than fueling my car. The correct answer to your three-line conversation is yes, you can use it in an apartment. You need a plug in your parking garage, maybe, but that's remarkably easy: a drill and a long copper rod can deliver energy through a solid concrete wall (just an example). Batteries aren't too heavy; ~500# is counterbalanced by the simpler engine. 300-mile range has been demonstrated with lithium-ion batteries and longer is possible with lithium-sulfur. We're not going to run out of lithium, either: http://gas2.org/2008/10/13/lithium-counterpoint-no-shortage-for-electric-cars/ http://gas2.org/2008/10/13/lithium-counterpoint-no-shortage-... Lithium-sulfur batteries have been my bet for a while. They're light and they could be commercialized in less than a decade. Plus, the specific power is huge, which means way faster charging times. http://www.springerlink.com/content/7382272v1u32m381/ http://www.springerlink.com/content/7382272v1u32m381/