fuel cells
fuel cells kinda suck. well, they're great if you want to make electricity. however electricity kinda sucks if you want to move stuff. like say a car. bmw's hydrogen powered car just burns the stuff. and it goes like hell. as one would expect from a bmw. current fuel cells generally require exotic materials like platinum or paladium. which they consume. there just isn't enough of that stuff on earth to feasibly put fuel cells in our autos. sorry. next idea.