Gas Fleet Concept Receives Approval in Principle

Sanjay Verma, W?rtsil?, Jim Smith, Lloyd's Register and Zhao Zhijian, CHI with the Natural Gas Operating Fleet concept's AiP Certification.

Published Apr 17, 2017 3:21 PM by The Maritime Executive

Wärtsilä and COSCO Shipping Heavy Industry have announced the joint development of a natural gas operating fleet concept which has obtained Lloyd's Register's (LR) Approval in Principle. 

The aim of the concept is to offer global operators a more efficient and economical fleet design that meets current and anticipated environmental requirements. The fleet comprises four vessels: a pusher tug, LNG storage barge, LNG regasification barge and a floating liquefaction natural gas barge. The pusher tug can be used to transport the three barges.

The concept's main advantages are its operative flexibility and the fleet's competitive CAPEX and OPEX costs, says Wärtsilä. The number and choice of units will depend on the project, since not all of the concept's units are necessarily needed for every project. For example, the concept can be utilized to act as an LNG carrier (using only the pusher tug and LNG storage barge), or it can be used for more complex projects involving liquefaction and regasification systems (using all units). 

The modular design of Wärtsilä's liquefaction and regasification units makes this an ideal concept for gas plants in the 50-200 MW range, says the company. The low draft design also makes it very attractive for gas power plant projects in South East Asia.

The project has attained the authority of China's National Patent Office and has been conceptualized by COSCO. The design and engineering development, especially in relation to the hinge joint, mooring arrangement, ship type and seakeeping analysis, was also carried out by COSCO. 

Wärtsilä supported this project through its experience and expertise in supplying LNG systems for the complete gas value chain. It is expected that when ordered, the fleet vessels will include Wärtsilä dual-fuel engines and steerable thrusters, the Wärtsilä LNGPac gas storage and supply system, a Wärtsilä liquefaction module, a Wärtsilä LNG cargo handling system and a Wärtsilä regasification module.

"LR has completed a preliminary hazard identification (HAZID) study for this innovative design. This study covered the fuel gas supply system, the transfer of LNG between the vessels, as well as the mooring arrangement of the fleet, and as a result the Approval in Principle certificate has been issued," says Wei Ying, Principal Specialist & General Manager, Shanghai Technical Support Office, Lloyd's Register Marine & Offshore.

The development project was carried out under the terms of a memorandum of understanding cooperation signed in June 2016 between the three companies.