Retrofitting Cruise Ships to LNG

DNV GL has recenlty issued a new report to evaluate the possibility of retrofitting existing cruise ships to run on LNG as fuel. Considering the cost of investments and fuel prices, LNG may be a cost- beneficial solution that meets the challenge for reducing air emissions.

2014.04.01 - Retrofitting Cruise Ships to LNG

The cruise industry is facing new and stricter IMO air emission regulations. Considering the cost of investments and fuel prices, LNG may, in the authors’ view, be a cost-beneficial solution that meets this challenge. In this report, the authors evaluate the possibility of retrofitting existing cruise ships to run on LNG as fuel, with the pros and cons attached.

A large number of cruise ships currently sailing to popular destinations will soon need to comply with stricter environmental regulations – requiring the installation of scrubbers, the use of LNG as fuel, or a changeover from heavy fuel oil (HFO) to marine gas oil (MGO) or a combination of these two. Compliance with regulations and the strongly fluctuating fuel prices have made cruise operators sceptical about the success of their future business.

A large number of cruise ships currently sailing to popular destinations will soon need to comply with stricter environmental regulations – requiring the installation of scrubbers, the use of LNG as fuel, or a changeover from heavy fuel oil (HFO) to marine gas oil (MGO) or a combination of these two. Compliance with regulations and the strongly fluctuating fuel prices have made cruise operators sceptical about the success of their future business.

Converting an existing cruise ship to run on LNG can in principle be done by:

  1. Taking the ship out of operation and installing the LNG tanks and fuel handling systems in the existing hull. Such a retrofit will reduce the number of cabins and will involve technical complications as the LNG tanks require more space than HFO or MGO fuel tanks and such free space is not available on the ship. In addition, this is time-consuming and thus represents a loss of revenue due to the lengthy off-hire.
  2. Inserting a new “LNG-ready” prefabricated mid-body section containing all the LNG systems, additional cabins and public spaces into the ship. Such a retrofit can be done in a few weeks, the ship does not need to go on a lengthy off-hire and the passenger capacity will increase by approximately 10%. The investment is limited to approx. 10% to 12% of newbuilding costs.

The DNVGL study focuses on the second option, which according to the study is proven to be the most feasible solution from a technical and financial perspective.

Retrofitting an existing cruise ship so that it can use LNG fuel is a feasible option for a number of existing cruise ships. The study presented above shows that every ship needs to be considered separately as each ship has unique design characteristics and limitations for the integration of a new section. The retrofit potential depends on the design and structural characteristics of each cruise ship and, based on that, technical showstoppers might arise. Another challenge the industry is facing at the moment is the size and location of the LNG tank due to the ship’s structural limitations and the rules and regulations currently governing the specific topic. The IMO rules have not yet been confirmed. The strictest set of rules currently under discussion limits the maximum allowable tanks size. The fuel that can be stored in the new mid-body section of a typical cruise ship is approximately 1,500 m3 which is equal to the energy of about 800 m3 of MGO.

The report is written by Alexandros Chiotopoulos (Consultant), Gerd-Michael Würsig (Segment Director), Atle Ellefsen (Chief Naval Architect), Helge Hermundsgård (District Manager).

Mr. Alexandros Chiotopoulos will be giving a presentetation on LNG as a fuel option for Bulk Carriers on the GREEN4SEA Forum which is to take place next week in Athens Eugenides Foundation.

The DNVGL study can be found by clicking HERE.

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