Exactly! The amount of energy required to produce hydrogen is greater then the energy output of the hydrogen! Hydrogen stores very low amount of energy compared to gasoline. It takes large amounts of electricity to produce a reasonable quantity of hydrogen that would sufficiently contribute to providing energy to push a piston down. Never mind getting into the dynamics of how hydrogen burns, burn rate, stoich, etc that would need to be accounted for in the engine to be efficient.
If there was any inkling of reasonableness to his claims I would be shoving snow down into my gas tank right now! LOL