Nippon Yusen Kabushiki Kaisha (President: Takanari Soga, Head Office: Chiyoda-ku, Tokyo), Kawasaki Kisen Kaisha, Ltd. (President: Koichi Akechimaya, Head Office: Chiyoda-ku, Tokyo), Mitsui O.S.K. Lines, Ltd. (President: Tsuyoshi Hashimoto, Head Office: Minato-ku, Tokyo), Imabari Shipbuilding Co., Ltd., and Japan Marine United Corporation's joint business design company, Nippon Shipyard Co., Ltd. (President: Kiyoshi Higaki, Head Office: Chiyoda-ku, Tokyo), Mitsui & Co., Ltd. (President: Kenichi Hori, Head Office: Chiyoda-ku, Tokyo), Mitsubishi Corporation (President: Katsuya Nakanishi, Head Office: Chiyoda-ku, Tokyo, hereinafter referred to as Mitsubishi Corporation) have obtained the Approval in Principle (AiP) for two types of low-pressure liquefied CO2 transport ships (LCO2 transport ships) from the American Bureau of Shipping (ABS, Headquarters: Texas) and the Nippon Kaiji Kyokai (NK, Headquarters: Chiyoda-ku, Tokyo).
The award ceremony was held on September 17 at the George R. Brown Convention Center in Houston, Texas, USA, which served as the venue for the Gastech 2024 international conference on global energy and environmental issues such as natural gas, LNG, and hydrogen.
In CCS (Carbon dioxide Capture and Storage) projects that transport domestically collected CO2 to storage sites, the demand for LCO2 transport ships as a means of maritime transport is expected to increase in the future. Mitsubishi Shipbuilding, Nippon Shipyard, Mitsui & Co., and Mitsubishi Corporation have been working on standardization of LCO2 transport ships and establishment of construction supply chains across projects in order to achieve stable construction and supply of LCO2 transport ships and realize cost-effectiveness in the CCS value chain. With the addition of Kawasaki Kisen Kaisha, Mitsui O.S.K. Lines, and Nippon Yusen Kabushiki Kaisha, the major shipping companies in Japan, we have obtained AiP for this project.
The LCO2 transport ships that have obtained AiP consist of two types: 0.05 million m3 class and 0.02 million 3,000 m3 class, which are designed for long-distance and large-scale transportation. In addition to applying appropriate tank materials instead of conventional nickel steel as the steel for cargo tanks, they also include a process that eliminates post-weld heat treatment (PWHT), which is an important issue in the establishment of the manufacturing process, through an engineering approach called ECA (engineering critical assessment).
Nippon Yusen Kaisha believes that the establishment of CO2 transport technology using large ships will greatly contribute to the realization of a carbon-neutral society. In the medium-term management plan "Sail Green, Drive Transformations 2026 - A Passion for Planetary Wellbeing -" announced in March 2023, LCO2 transport is positioned as one of the new businesses actively invested in, and we are promoting co-creation with partner companies in Japan and overseas.

The AiP award ceremony was held at Gastech 2024.
From left to right.
Second person: Kawasaki Kisen Kaisha, Ltd. Executive Officer Mr. Satoshi Kanamori
Third person: Mitsui & Co., Ltd. Executive Officer Mr. Takuya Shirai, Head of Mobility Division
Fourth person: Mitsui O.S.K. Lines, Ltd. Senior Executive Officer Mr. Naoshi Umemura
Fifth person: Japan Shipyard Co., Ltd. President Mr. Kiyoshi Higaki
Sixth person: Mitsubishi Shipbuilding Co., Ltd. President Mr. Shin Ueda
Seventh person: Mr. Patrick J. Ryan, Senior Vice President and Chief Technology Officer, ABS
Ninth person: Nippon Yusen Kabushiki Kaisha Executive Officer Mr. Tsutomu Yokoyama
Tenth person: Mitsubishi Corporation, Social Infrastructure Group, Infrastructure, Ship & Aerospace Headquarters, Head Mr. Mikito Nakaba

(Note 1) Approval in Principle (AiP) means that the certification body reviews the basic design and approves it if it meets the technical and safety standards. This time, the inspection was carried out based on the IGC Code and the rules of each classification society (ABS, NK) for ships carrying liquefied gas in bulk.
(Note 2) The International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk (IGC Code) specifies the safety requirements for ships carrying liquefied gases such as LCO2 and LNG as bulk cargo. It is an international regulation.
(Note 3) Post Welding Heat Treatment (PWHT) is a process that involves reheating the structure after welding, holding it at a specific temperature for a certain period of time to reduce residual stress, and aiming to improve the quality of the weld joint. This process is commonly carried out by placing the structure in a dedicated furnace, and in the case of large structures, the size of the furnace can become a bottleneck in the production process.
(Note 4) Engineering Critical Assessment (ECA) is a method for evaluating the safety of welded structures, using the anticipated stress history and small initial defects in the weld to confirm that there will be no significant quality issues with the weld joint during the service life of the structure, based on the material and welding characteristics.