Fuel Cells for Shipping: To Meet On-board Auxiliary Demand and Reduce Emissions

The reduction of harmful emissions from the international shipping sector is necessary. On-board energy demand can be categorised as either: propulsion, or auxiliary services. Auxiliary services contribute a significant proportion of energy demand, with major loads including: compressors, pumps, and HVAC (heating, ventilation, and air-conditioning). Typically, this demand is met using the same fuel source as the main propulsion (i.e. fossil fuels). This study has analysed whether emissions from large scale ships could feasibly be reduced by meeting auxiliary demand by installing a hydrogen fuel cell, using data from an LNG tanker to develop a case study. Simulations have shown that for a capacity of 10 x 40ft containers of compressed hydrogen, the optimal fuel cell size would be 3 MW and this could save 10600 MWh of fossil fuel use, equivalent to 2343 t of CO2. Hence this could potentially decarbonise a significant proportion of shipping energy demand. Although there are some notable technical and commercial considerations, such as fuel cell lifetime and capital expenditure requirements. Results imply that if auxiliary loads could be managed to avoid peaks in demand, this could further increase the effectiveness of this concept.