You can burn hydrogen in ICE engines as well. In the 2000's both BMW and Mazda did limited series developments of cars that can be switched between burning gaso

You can burn hydrogen in ICE engines as well. In the 2000's both BMW and Mazda did limited series developments of cars that can be switched between burning gasoline and hydrogen - the BMW 750 with the M73 V12, and the Mazda RX-8 with the dual rotor Renesis Wankel engine. Currently batteries (and possibly fuel cells) seem to be winning out for cars, but burning hydrogen in large piston engines seems to be a promising option for ships. I've heard Yanmar is currently developing a large slow two-stroke marine engine burning hydrogen, probably in the 5 MW range.