Press Release

29 October 2025

Tokyo - ClassNK has released "Guidelines for Onboard CO2 Capture and Storage Systems (Edition 2.0)" first in the world, which assumes onboard CO2 capture systems (OCCS) using membrane separation method which are expected to be applicable to a wide variety of vessel types. The guidelines can be supported the safety development, manufacturing, and installation of relevant system.

Not only fuel transition, but interest in capturing CO2 from ships' exhaust gas is growing as a way to reduce GHG emissions, and the development of onboard systems for capturing and storing CO2 is being undertaken. In 2023, ClassNK published the first edition of the "Guidelines for Onboard CO2 Capture and Storage Systems" which outlined requirements for OCCS using amine absorption method.

In the newly issued Edition 2.0, the guidelines have been expanded to include requirements for OCCS using membrane separation method which is lower energy requirement compared to amine absorption method and does not require a permanent supply of amine solution.

In addition to that, ClassNK has reorganized the fundamental functional requirements for OCCS, extracted the common requirements across different capture methods, and compiled them into a set of generic requirements that should apply regardless of the specific capture method.

The guidelines are available to download via ClassNK's website www.classnk.com for those who have registered for the ClassNK "My Page".
https://www.classnk.or.jp/account/en/Rules_Guidance/ssl/guidelines.aspx



For inquiries about this press release:
ClassNK Machinery Department
Tel: +81-3-5226-2022
E-mail: mcd@classnk.or.jp

For media-related inquiries:
ClassNK Public Relations Team
4-7 Kioi-Cho, Chiyoda-Ku, Tokyo 102-8567 Japan
E-mail: eod@classnk.or.jp

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