The focus of the study DNV GL’s 20,000 TEU PERFEC(T) LNG-fuelled cargo ship design.
The study was carried out in partnership with large French container ship operator CMA CGM Group and LNG cargo tank manufacturer GTT.
It compared the PERFEC(T) design featuring LNG-fuelled combined cycle gas and steam turbine (COGAS) propulsion with a conventional HFO-fuelled cargo ship with the same hull shape and a scrubber system on an Asia-Europe voyage.
Investment costs of the additional and reduced systems to the base case were considered.
DNV GL said: “The final result showed that the overall efficiency of the COGAS system and that of the HFO-fuelled 2-stroke engine system are very close to each other.”
The society expects that fine tuning of the new COGAS components to increase efficiency “well above the efficiency of the conventional system.”
In the design space normally occupied by the engine room and the funnel structure was used for cargo, a result of placing the COGAS system and LNG tanks at deck level within the deck house area.
“The potential for an optimized LNG-fuelled COGAS system goes even beyond the efficiency of the oil-fuelled engine systems used today,” the study noted.
“At the same time, cargo capacity is increased by the use of LNG and not decreased as is the case for LNG-fuelled piston engine systems.
“In fact, the cargo capacity is higher than the capacity of a conventional oil-fuelled ship of the same size.”