Advancing toward Net-Zero Emissions
Given the worldwide acceleration of efforts to decarbonize society by transitioning to new types of energy, the NYK Group has set the achievement of net-zero emissions by 2050 as its long-term goal for reducing greenhouse gas emissions. With our sights set on this goal, we are advancing a variety of initiatives. One initiative that is making steady progress is a project for the commercialization of vessels equipped with a domestically produced ammonia-fueled engine. Ammonia does not emit CO₂ when burned.
On August 23, 2024, as part of the ammonia-fueled vessel development project, the ammonia-fueled tugboat Sakigake—the world’s first commercial ammonia-fueled vessel—was completed. In 2015, Sakigake was completed as an LNG-fueled tugboat and became the forerunner of NYK’s LNG-fueled vessels, which NYK continues to introduce to its fleet. The conversion of Sakigake into an ammonia-fueled tugboat required overcoming technical difficulties. This vessel represents a big step forward in leading the maritime shipping industry’s decarbonization efforts.
Combining Technology and Expertise to Realize Conversion
As the NYK Group works together toward achieving net-zero emissions by 2050, the actual conversion work for Sakigake was undertaken by Keihin Dock Co., Ltd., a member of the NYK Group.
Keihin Dock was established in 1968 with capital from NYK as a company engaged in the building and repair of small ships. Keihin Dock expanded its shipbuilding business after opening its Oppama plant in 2003 in Yokosuka, Kanagawa Prefecture. In 2013, the company built Tsubasa, Japan’s first environmentally friendly tugboat fitted with a hybrid propulsion system, followed in 2015 by Sakigake, Japan’s first LNG-fueled tugboat. Including the recent conversion to an ammonia-fueled tugboat, Keihin Dock also plays a role in the research and development of next-generation technologies aimed at realizing the NYK Group's decarbonization strategy.
Kunihiro Niimi, who is general manager of the Ship Design Department and has been involved with tugboats at Keihin Dock for 30 years, explains the conversion.
“It was the first time we had replaced the equipment of an existing hull. We were able to utilize the experience we gained from building Sakigake as an LNG-fueled tugboat, but we faced completely different challenges compared to designing a new tugboat. We had to establish a layout for the ammonia-related equipment in a confined space that had a predetermined design. At the same time, we had to formulate rules to ensure safety in relation to ammonia, which is highly toxic and can endanger human life.”
The conversion process was complex. The hull of Sakigake was cut away, LNG-related equipment was removed while leaving equipment that would continue to be used, and ammonia-related equipment was installed on board the vessel. This included the engines and fuel tanks, as well as the piping and valves connecting them.
Kenta Tojo, who belongs to the Manufacturing Department and was not only involved in the construction of the LNG-fueled tugboat Sakigake but also in charge of this project, recalled construction on-site.
“Before cutting, we knew where everything was. So, identifying what was to be removed and what was to be left went smoothly. As the construction progressed, however, many unexpected situations arose, including layout changes and additional removals. Each time, we had to review the time schedule of work and make adjustments with the craftspeople, designers, and others involved.”
Toshimitsu Shimizu, also a member of the Ship Design Department, mainly worked on piping design. He reflected on his experience in this project.
“The construction work would not have been possible without the 3D design.”
2D drawings of spaces with complex piping must be significantly redrafted each time a single pipe is replaced. In addition, it is not possible to completely grasp the situation using 2D drawings alone. 3D drawings enable anyone to view and grasp situations three-dimensionally, making it possible for personnel in charge of on-site construction, such as Tojo, craftspeople, and crew members who will actually work on board the vessel, to hold discussions that are based on a better understanding of actual situations.
As the complex construction work proceeded, equipment had to be correctly installed in confined spaces. The complexity of the process was like replacing a human heart while leaving certain blood vessels in place. The unprecedentedly difficult construction work was advanced by bringing together the skills and experience of people with different areas of expertise.
Proceeding along an Unexplored Path with Cooperation
Commercial ammonia-fueled vessels are not found anywhere in the world. Niimi explains that the vessel’s unprecedented nature required an exacting approval process.
“We had to build a vessel that would pass inspections and thereby gain recognition as being safe for operation at sea. Specific rules do not exist for using ammonia fuel, which is highly toxic. So, as we proceeded, we discussed the interpretation of rules with the ship classification society ClassNK and the Japanese government.”
Shimizu added, ”We also had to evaluate and consider safety by conducting a HAZID* risk assessment. Meetings were held to determine measures in the event of disasters and to assess the risks after these measures. The rules decided on through such meetings had to be directly reflected in the vessel. In addition to the rules, we had to meet the safety requirements established through risk assessments, which was also nerve-wracking.”
Inspections of the piping through which ammonia fuel passes were attended by a chief engineer from NYK Group company Shin-Nippon Kaiyosha, which operates tugboats in Tokyo Bay. He served on board the LNG-fueled tugboat Sakigake for eight years and is responsible for the operation of the converted Sakigake as well. He was present at the tests to provide the viewpoint of crew members. Tojo emphasizes the important contribution made by the chief engineer.
“The chief engineer arrived at the dock earlier than scheduled. He read the drawings carefully until he thoroughly understood all of them. Then, during the inspection he made precise suggestions based on the particular viewpoint of a crew member. Without the chief engineer, we would not have been able to conduct the complicated inspection. So, I felt that the full cooperation we received demonstrated a strength of the NYK Group.”
Before installing equipment to create the world’s first commercial ammonia-fueled vessel, close collaboration with all parties involved was undertaken to implement every conceivable measure and countermeasure. Further, after the vessel had been retrofitted, adjustments continued to be made during test operations. Niimi explains the meticulous process.
“In the end, we checked several hundred items when confirming the operation of safety devices and engine equipment. If anything failed, we made adjustments and checked the item again, beginning from the initial procedures.”
At all stages, from design through to conversion work and test operations, the project has overcome unprecedented, difficult challenges one at a time thanks to the steady, patient efforts of everyone involved.
Sharing a Commitment to the Creation of High-Quality Ships
The cheerful expressions on the faces of the three personnel as they talk contrast with their account of 10 months of hectic, complex remodeling work. Shimizu recalls how he felt at the time.
“While we were in the midst of working on the vessel, I could not imagine it actually operating at sea.”
Tojo had a similar feeling.
“When preparing work schedules, I sometimes could not envision the work ever ending.”
When asked how he managed to complete the project despite the difficulties, Tojo replies that affection for the vessel was a motivator.
“When asking myself why I was able to work so hard, I realized that I have a strong attachment to Sakigake. Cutting open a vessel I had built made me very sad. But, as we replaced the equipment, my mood changed. I developed a strong desire to make an even better vessel.”
Dedication to manufacturing is also important for Niimi.
“The fun part of being involved in manufacturing and tugboat construction is that, beginning with nothing, you bend steel plates into shape to form a vessel. Then, it goes out into the world and plays an important role. Even if a vessel that you have built is sold, repainted, and renamed, you can still recognize it.”
The ability of on-site personnel to complete the project greatly impressed Shimizu.
“As no one had ever built such a vessel before, a large number of points required attention. Nonetheless, personnel worked together on-site to rapidly select the best measures and formulate solutions in short periods of time. Amid such a trying situation, I was struck by their ability to create a vessel that truly performs well. Moreover, they did so without any major accidents. The on-site team’s competence really impressed me.”
Tojo points out that the craftspeople at Keihin Dock not only possess excellent skills but are also generous in drawing on their experience to offer suggestions aimed at solving problems.
“People from outside the company often remark on how helpful our craftspeople are. When building a ship for the first time in several years, one supervisor of a shipowner even asked for a specific craftsperson to be assigned to the project.”
In the building and repair of ships, even in the midst of construction, the company often seeks specific suggestions and requests from partner companies, customers, and the crew members who will actually work on board the ship. Frontline personnel then endeavor to incorporate such feedback. They want to build outstanding ships. This shared ambition fosters on-site teamwork, which extends from the Ship Design and Manufacturing departments to the rest of the company and even reaches beyond it.
Thinking about the NYK Group as a whole, Niimi explains that teamwork is crucial.
“This project is led by NYK, our parent company. Since we are an NYK Group company engaged in shipbuilding, we were tasked with converting the vessel. I believe that the success of the project is attributable to co-creation. As was the case with the hybrid tugboat Tsubasa and the LNG-fueled tugboat Sakigake, such new, specialized vessels are difficult for individual companies to realize on their own. I think the advantages of a large project in which everyone is focused on the same goal were fully demonstrated in the conversion of Sakigake.”
Pursuing Decarbonization as a Shared Goal
The recent conversion work was part of a project to develop vessels equipped with domestically produced ammonia-fueled engines to achieve net-zero emissions. But Keihin Dock is not limiting itself to ammonia-fuel tugs. The company is very interested in all next-generation fuel tugboats. The world's first commercial ammonia-fueled vessel has now been realized, and the search for the next advancement continues, stressed Niimi.
“We still do not know which energy source is most appropriate for tugboats. If we are affected by trends among automakers, all-solid-state batteries may eventually become the mainstream. I want to continue looking ahead to likely future trends in this area.”
Continuing, Niimi explains how shipyards can contribute to decarbonization.
“As these trends emerge and develop, shipyards can contribute to decarbonization not only in relation to fuel but also with respect to hull design. In other words, we can explore hull shapes that reduce drag and increase fuel efficiency without compromising ship performance. I believe that continuing to search for such solutions will be our contribution to ambitious decarbonization initiatives.”
The NYK Group will continue to progress toward realizing a decarbonized society by leveraging the strengths of each Group company while co-creating with other companies.
Through the pursuit of goals shared by the whole Group and an unwavering commitment to building high-quality ships, Keihin Dock will undoubtedly help decarbonize society and thereby open the way to a better future.
(Interview October 4, 2024)
- * HAZID（Hazard Identification Study）
HAZID is a safety assessment method whereby evaluations are conducted by identifying items based on potential risks. When creating new structures and systems, their impact on human life, property safety, and the environment is envisioned in various scenarios, and the magnitude of the risks is evaluated.