Energy: ENEA, technological solutions for the cruise industry

A study on the large cruise ship sector, published in the scientific journal Energies and conducted by ENEA and the University of Rome "Sapienza" among others, shows that fuel cells consume up to 20% less than a traditional engine, offering higher energy efficiency (60%).

"We compared the performance and costs of a conventional generator and an SOFC^[1], fuel cell, both powered by liquefied natural gas (LNG), operating at 1 MW of power on a large cruise ship with a tonnage of over 100,000 tons" explained Manlio Pasquali, one of the authors of the study, a researcher at the ENEA Sustainable Mobility and Transport Laboratory. "Current cruise ships" he said "powered by LNG, could represent a major shift toward reducing polluting emissions through limited intervention, by integrating high-temperature fuel cells to power on-board electrical services that require a minimum stable power supply like air conditioning, refrigerators and cabin lighting."

The study shows that to produce the same 1 MW of energy, an innovative fuel cell system consumes 287 liters of LNG per hour compared to a conventional generator which requires 331.5 liters. "In addition to reduced consumption by up to 20% and greater efficiency (around 60%), fuel cells ensure less space required for fuel storage or, alternatively, longer operational autonomy for the same tank volume" said Pasquali.

In addition to the benefits in terms of consumption, fuel cells offer significant environmental advantages: since they generate electricity through an electrochemical process rather than combustion, they do not emit particulate matter or nitrogen or sulfur oxides and drastically reduce CO₂ emissions compared to internal combustion engines. "Although the fuel cell system faces drawbacks like greater weight and volume (40% and 75% respectively) and upfront costs up to six times higher, annual operating costs are significantly reduced thanks to reduced LNG consumption," concluded Pasquali.

The authors plan to extend the study to utilize part of the heat generated by SOFC fuel cells to produce hydrogen for use in PEM fuel cells (typically fueled by hydrogen), which are more suitable for operating at variable power, such as in marine navigation. This approach could lead to the development of a hybrid propulsion system combining SOFC, PEM, and traditional technologies to optimize efficiency, flexibility and sustainability.

Currently, shipping companies are redisigning large cruise ships to comply with stricter environmental regulations with the goal of reducing emissions, increasing efficiency and reliability and significantly reducing maintenance time and costs. With the European Commission's Fuel EU Maritime initiative, the maritime sector has been included in the Fit for 55 package, which calls for a 50% reduction in emissions by 2030 and a 90% reduction by 2050. The initiative promotes the use of sustainable fuels in maritime transport and European ports, addressing market barriers and technological uncertaintes that limit their adoption.