people in the know are not very keen on hydrogen because the use of it in vehicles is not really a solution to the time when the oil wells all dry out (in about 30 years time). using hydrogen simply transfers the burden of energy production from one place (the gasoline or diesel engine in your car) to another (the power plants that will provide the tremendous amounts of electricity needed to separate hydrogen from H2O, to liquify it and then to store it). and hydrogen powered internal combustion engines are also not that efficient.

electric cars are more promissing than hydrogen powered cars. the reason is simple. the best electric motors run at almost 99% efficiency while internal combustion engines theoretically can only go as high as 37%. so why double the losses (produce hydrogen using a nuclear power plant running at 47%, then produce mechanical power in the car using an internal combustion engine) when you can eliminate most of the losses in the car by using batteries and electric motors.

one possible use of hydrogen is in electric cells that power electric motors, but that too is too heavy and by its weight alone will negate whatever increase in efficiency provided by the electric motors.

in the end, i believe, the electric motor-battery combination will prevail over the hydrogen-internal combustion engine or the hydrogen power cell-electric motors. reason is simple, they already have plastic batteries that can store more energy that ordinary lead acid battery, and it will not be long before they can put as much electric energy in a battery the size of a gas tank and still give the same mileage as 1 tank of 95 octane.

although this solution still does not get away from the problem stated in the first pharagraph above (transferring burden of energy production), if the fusion reactors they are working on will work then that is no longer an issue. the world can have all the energy it needs and not be afraid of ever running out.