Hummer made a "proof of concept" vehicle that basically turned the Hummer SUT (which is what I have) into a hydrogen powered vehicle. The engine actually stayed the same (the Vortec V8), but was modified to work on hydrogen.

Now for the funny part... The hydrogen system is less powerful than the normal gasoline system, so they added a super charger to bring it up to 180hp (a little more than half the horsepower of the gasoline version without a supercharger). Which gave it comparable performance to the gasoline counterpart. You think a gasoline powered Hummer uses a lot of gas? The hydrogen powered version needs to be refueled every 60 miles.

Oh well, at least they are working on it...

Speaking of which, some Australian dudes may have come up with a way to economically (and quickly) generate hydrogen from water using sunlight. The current way to make hydrogen in large quantities involves using a whole bunch of fossil fuels... Kind of stupid to burn up a bunch of fossil fuels just to make a clean burning fuel in the end... stupid.