Next summer, I am starting on a project- a full-out tube frame aluminum skinned 4x4, about the size and style of an Explorer, with a bit of a twist. The truck will be moved by electric motors, one on each end, drawing from a battery pack under the back seats and cargo floor. There will be an engine, a little four cylinder Deutz air cooled diesel, but all it will turn is an alternator to charge the batteries. On when the computer needs more juice, off when batteries are enough. I'm still trying to figure out how to control it, ironing out the designs for steering, brakes, and suspension system, as well as overall appearance. I am having a hell of a time figuring out fuel economy, but it looks like I should be able to hit the 60mpg mark.
A setup like this, running on biodiesel is a currently available economical alternative. Hydrogen technology is too far off to count on, and even when it gets here, it's not very usable. Someday, it may be useable in cars, but until then something else is needed.