Utilization of waste heat for onboard hydrogen production in ships

The ship is a complex system that meets its own power demand during operation. The total power need differs and it is mainly provided by the main engine and energy sources derived from it. Additionally, the auxiliary systems as generators, and boilers also operate when needed so as to meet heat and electricity demand. The study reveals the potential of excess heat to produce H₂ which can replace auxiliary energy demand so as to reduce auxiliary systems’ carbon emissions with the help of Polymer-electrolyte membrane (PEM) electrolysis. Hydrogen can be produced environmentally friendly way on board from waste heat sources during operation and stored as compressed form. The amount of available excess exhaust heat energy from the main engine, the efficiency of electrolyser and the PEM fuel cell efficiency determine the proportion of the excess energy, be used later. Study aims even a small amount of energy must be used to develop a less carbon energy approach in ships and shows 0.5 % annual saving can be achieved with excess heat conversion to H₂.