Just days after The Carbon War Room unveiled its new shipping efficiency site, DNV has introduced a new crude oil tanker concept, dubbed Triality, that it says is fueled by liquefied natural gas, has a hull shape that removes the need for ballast water and will almost eliminate local air pollution. The concept vessel also recovers hundreds of tons of cargo vapours on each voyage.
Triality is a concept vessel and a ship builder will need to prepare a detailed design before the first tanker can be constructed.
In comparing the new concept vessel to a conventional VLCC, DNV says both ships have the same operational range and can operate in the ordinary spot market. In addition, the Triality VLCC will emit 34% less CO2 and use 25% less energy. NOx emissions will be reduced by more than 80% while emissions of SOx and particulate matter will fall by as much as 95%.
The new concept tanker has two high pressure dual fuel slow speed main engines fuelled by LNG, with marine gas oil as pilot fuel. The next phase of the Triality concept development will review the use of dual fuel medium speed engines and pure gas engines.
Two IMO type C pressure tanks capable of holding 13 500 m3 LNG - enough for 25 000 nautical miles of operation - are located on the deck in front of the superstructure. The generators are dual fuel (LNG and marine gas oil) while the auxiliary boilers producing steam for the cargo oil pumps operate on recovered cargo vapours (VOCs).
A traditional tanker in unloaded transit needs ballast water to obtain full propeller immersion and sufficient forward draft to avoid bottom slamming. The new V-shaped hull form and cargo tank arrangements eliminates the need for ballast water in the VLCC version. There will also be much less need for ballast water on other kinds of crude oil tankers, such as Suezmax, Aframax and smaller ships. The new hull shape results in a reduced wetted surface on a round trip and has a lower block coefficient and thus a more energy efficient hull.
DNV says its best estimate is an additional capital expenditure of 10-15% for a Triality VLCC newbuilding compared to a traditional VLCC. With this extra cost included, the company estimates a reduced life cycle cost equal to 25% of the newbuilding cost for a traditional VLCC.
