LNG – The Future For Cruise Ships?

Costa's 180,000gt LNG ship

Costa’s 180,000gt LNG ship

June 2015: The Carnival Corporation announced that they have finalized a multi-billion dollar contract to build four next-generation cruise ships with the largest guest capacity in the industry.

This is part of a larger order with shipbuilders Meyer Werft and Fincantieri for nine new ship orders between 2019 and 2022.

The four new ships will also feature a new “green cruising” design. The ships will be the first in the cruise industry to be powered at sea by Liquefied Natural Gas (LNG). They will use LNG in dual-powered hybrid engines to power the ship both in port and on the open sea. LNG will be stored on-board and used to generate 100 percent power at sea. Using LNG to power the ships in port and at sea will eliminate emissions of soot particles and sulphur oxides.

April 2016: The Mediterranean Shipping Company (MSC) SC Cruises has announced today that it has signed a letter of intent (LOI) with STX France for the construction of up to four* new LNG-powered cruise ships that will be more than 200,000 tons. The ships will be able to carry 5,400 passengers at double occupancy. (*Two firm orders, two options.)

The four ships, the first one of which will be delivered in 2022, will be based on a new advanced next-generation prototype and will form what will be known as the “World Class” of MSC Cruises’ ships.

What is LNG?

Using LNG to power ships is not a completely new idea. However to date, LNG use has been restricted to smaller vessels operating rather short runs. This is due to the large size of fuel tanks required and the few bunkering facilities available. However it is a new idea for cruise ships and certainly for a megaship design.

LNG is superior to pipeline gas in quality. This is because LNG is purer, has more methane as well as other energy content, and also because of its chemical structure since it has a stable composition. Its combustion generates no unburned residues, particulates or soot, and releases less greenhouse gas than traditional marine gas oil (MGO). Future maritime emissions regulations, especially in sensitive environments are likely to demand this. Perhaps the most appealing aspect about LNG is that under the right operating conditions it can reduce fuel costs.

In addition, using  LNG can double the maintenance intervals, because the gas is so clean,  ship owners may get  25,000 hours between maintenance intervals, maybe more, opposed to 12,500 hours with standard fuel.

Viking Grace, LNG Ferry

Viking Grace, LNG Ferry

Here is an interesting example: VIKING GRACE is a European passenger ferry (2013, 57,000gt, STX, Finland) powered by LNG. Gas take up more space than fuel-oil. In fact six times more space. Therefore large tanks for the gas are located on deck, of the ferry, to save space in the hull (See image above).

However the renderings of  Carnival’s newbuilds do not appear to have LNG storage tanks on the deck.

(Source unknown)

(Source unknown)

LNG cruise ship ‘concepts’ have been around a long time. The renderings below are a design by Wärtsilä, the marine engine company.

(Image courtesy of Wärtsilä)

(Image courtesy of Wärtsilä)

Interestingly the concept ship uses drive shaft technology, rather than pods. The LNG tans are located internally, below the funnel area.

2-ship-innards

( Wärtsilä)

The engines on-board the new Carnival ships will not exclusively be powered by LNG, but will be ‘dual fuel’ being capable of burring both LNG and liquid fuel, and combinations of both at the same time. burning exclusively LNG could be saved for environmentally sensitive areas. This would reduce the fuel storage space required.

Malcolm

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