Towards Optimized Maritime Energy: Focus on an Energy Analysis and Management to Replace Conventional Power Systems with Hydrogen Solutions

This work presents an initiative carried out within the framework of the EU co-founded sHYpS project (Sustainable HYdrogen powered Shipping), aiming to propose a solution to achieve decarbonization goals of the maritime sector. Focused on cruise navigation in Norwegian Fjords, zero-emission shipping was achieved by installing a hydrogen-fueled low-temperature fuel cell system. This required the redesign of the shipboard systems and the implementation of energy-saving strategies to reduce consumption. Fuel cells integration significantly impacts the overall energy balance, as the high-temperature waste heat generated by internal combustion engines (which is currently used almost entirely for the heating, ventilation and air-conditioning systems) is no longer available. Instead, fuel cell power plants produce less waste heat at lower temperatures, thus presenting a critical challenge in reimagining the energy flows management to fully leverage the available waste heat from fuel cells, by minimizing fuel consumption. The analysis was conducted on a cruise ship with a capacity of 998 guests, 465 crew members, 54,300 GT of gross tonnage, 239 meters long, and a conventional power installation of 23.5 MW. The fuel cell system was integrated alongside the traditional conventional power plant and an energy analysis and management has been carried out to minimize both thermal and electrical energy consumptions while maintaining adequate comfort levels, reducing the required electrical power, and limiting the amount of hydrogen storage needed. Results show that achieving a zero-emission sailing day is feasible, though, certain energy-related limitations must be implemented. Additionally, the potential to leverage the ultra-low-temperature cold flow of liquid hydrogen to reduce power demand has been explored. Although the high costs of system development may present a significant barrier to its onboard implementation at these early stages of design, significant benefits might be achieved in the future.