"Great. Where are you going to get the hydrogen from?......PDR"
You 'split' sea water into its constituent oxygen and hydrogen gases using electrolysis. We did it in chemistry at school. You just need sea water and electricity connected to two electrodes submerged in the water. A chemical reaction takes place and the hydrogen gas accumulates above the negative electrode, the oxygen above the positive.
Use wind turbines, solar panels or tidal flow turbines to provide the electricity to split the seawater, and you produce hydrogen.
Note: Sea water rather than pure water because the salts in the seawater make it electrically conductive.