That is key. From what I have read this is NOT a hydrogen producing device, but an enhanced reverse osmosis device. That provides water to a conventional electrolytic cell. You could just electrolysis sea water directly. You will get hydrogen and chlorine. I don't know which would be more energy efficient. The chlorine would also be a useful product.

Besides hydrogen is not close to the fuel of the future.

>Water electrolysis has not yet been implemented on a large scale >Only four per cent of all hydrogen produced worldwide are the result of water electrolysis. As the electrodes used in the process are not efficient enough, large-scale application is not profitable. **To date, hydrogen has been mainly obtained from fossil fuels, with large CO2 volumes being released in the process,**says Wolfgang Schuhmann. "If we succeeded in obtaining hydrogen by using electrolysis instead, it would be a huge step towards climate-friendly energy conversion. For this purpose, we could utilise surplus electricity, for example generated by wind power."