"The challenges facing the use of hydrogen in vehicles include production, storage, transport and distribution. The well-to-wheel efficiency for hydrogen, because of all these challenges will not exceed 25%."
From Richard Heinberg:
"For the past decade or so energy experts have debated whether the best energy carrier for a post- fossil fuel energy regime would be electricity or hydrogen.96 The argument for hydrogen runs as fol- lows: Our current transportation system (com- prised of cars, trucks, ships, and aircraft) uses liquid fuels almost exclusively. A transition to electrifica- tion would take time, retooling, and investment, and would face difficulties with electricity storage (discussed in more detail below): moreover, physi- cal limits to the energy density by weight of elec- tric batteries would mean that ships, large trucks, and aircraft could probably never be electrified in large numbers. The problem is so basic that it would remain even if batteries were substantially improved.
Hydrogen could more effectively be stored in some situations, and thus might seem to be a better choice as a transport energy carrier. Moreover, hydrogen could be generated and stored at home for heating and electricity generation, as well as for fueling the family car.
However, because hydrogen has a very low ener- gy density per unit of volume, storage is a problem in this case as well: hydrogen-powered airplanes would need enormous tanks representing a sub- stantial proportion of the size of the aircraft, and automobiles would need much larger tanks as well.
Moreover, several technological hurdles must be overcome before fuel cells—which would be the ideal means to convert the energy of hydrogen into usable electricity—can be widely affordable. And since conversion of energy is never 100 percent efficient, converting energy from electricity (from solar or wind, for example) to hydrogen for storage before converting it back to electricity for final use will inevitably entail significant inefficiencies.
The problems with hydrogen are so substantial that many analysts have by now concluded that its role in future energy systems will be limited (we are likely never to see a “hydrogen economy”), though for some applications it may indeed make sense."
Basically, there are good reasons why there has not been a switch en masse to hydrogen: it is inferior to oil.