Application of high temperature fuel cell powered by LNG on ferry boat: a case study

Ships at berth use auxiliary Diesel engines to generate electricity on-board. The high levels of contaminants and GHGs detected in the seaport areas stimulate the search both for alternative power sources and for high efficiency technologies with low environmental impact. According to this, the present work is a case study of a ferry boat supplied by LNG and powered by a high temperature fuel cell of solid oxide (SOFC) type. The ferry boat is designed to connect the Gulf of Naples to the island of Ventotene and Ponza, and in addition the islands of Capri, Ischia and Procida, using dual fuel diesel/LNG engines with a stay in port period of 16 hours per day requiring about 100-200 kW. In the case study it is considered that the ferry boat is equipped with a 600kW auxiliary power unit (APU) based on a SOFC fuelled by LNG (gasified). Such a sys-tem does not require any complex fuel treatment system and can be used in cogenerative configuration allow-ing high efficiency (> 85 %). Technical data of SOFC-APU systems are taken from commercial products. The design of the entire system fuelling-APU has been obtained and the required volume, weight, LNG consump-tion have been calculated and compared with the specific of a MAN dual fuel generating set. The minimum volume of the SOFC-APU is about 145 m3, corresponding to a weight of 27 t, and considering additional 200 kW for redundancy. This requires about 69% of the designed volume for the auxiliary power plant room with a weight of about 52% lower. Results indicate that the use of SOFC-APU allows to save about 74% of LNG in comparison to the dual fuel engine. The environmental impact is also estimated calculating the SOx, CO, NOx, PM and CO2 emissions. It results that such a system reduces significantly emissions in the harbour of 99.9-100% of contaminants and about 53% of CO2.