Hydrogen is not an energy source, it is an energy carrier, you have to make the hydrogen from other chemicals (water electrolysis, methane reforming) using other forms of energy, which is not particularly efficient (~80%), then you have to transport it and store/compress it, also not particularly efficient (another 20%+ loss). Finally you have to convert the hydrogen back into electricity at ~50%. This gives a well to wheel efficiency of around 30-35%. For a battery vehicle well to wheel is of the order of 70%, HFCV & BEV both assume renewable electricity source.
Once battery technology has improved a bit more in the next few years (i.e. reduced price and better capacity) hydrogen vehicles are unlikely to be competitive as the running costs of HFCVs will be double, possibly more, than that of BEVs.