Research report 13 July 2026

Applying Onboard Carbon Capture & Storage Systems to ships

As carbon pricing tightens and fuel transition options remain constrained, shipowners face growing pressure to reduce emissions from vessels that will continue operating well into the 2030s and beyond. Retrofitting Onboard Carbon Capture and Storage (OCCS) is emerging as one of the few solutions capable of delivering meaningful CO₂ reductions for ships already in service.

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This Retrofit Research Programme report provides the most comprehensive assessment to date of OCCS as a real-world retrofit option, grounded in operational evidence, classification experience and an honest assessment of technical, regulatory and commercial constraints.

Based on current projections, much of the global fleet will continue to burn carbon-containing fuels for years to come. Energy efficiency improvements alone cannot deliver the reductions required, and fuel switching is often constrained by vessel design, fuel availability and remaining asset life. Onboard Carbon Capture addresses the carbon after combustion, making it applicable across Heavy Fuel Oil (HFO), Very Low Sulphur Fuel Oil (VLSFO), Marine Diesel Oil (MDO), Liquefied Natural Gas (LNG) and others.

This report focuses on the central question facing shipowners today: What does it really take to retrofit onboard carbon capture on an operating vessel – and when does it make commercial sense? Subjects covered in the report include:

Technology readiness: Independent assessment of all major OCCS technology routes, with a focus on what can actually be installed today. With comparison of post-combustion, pre-combustion, cryogenic, membrane and solid-sorbent systems. Marine technology readiness levels, from pilot concepts to classed commercial installations are reference
Retrofit integration : Practical guidance on integrating OCCS into existing ships, taking account of space, weight, stability and cargo trade-offs explained by vessel type. Including information on energy penalties and how waste-heat recovery changes the picture. Plus safety, hazardous-area management and crew considerations
Regulation and classification – How OCCS is treated under EU ETS, FuelEU Maritime, UK ETS and IMO frameworks. What captured CO₂ needs to qualify for compliance credit. The role of classification while international rules are still evolving and how risk-based approval enables projects to move ahead today
Economics and decision-making - Capital and operating cost drivers, with uncertainty clearly stated. Carbon abatement costs under different carbon price scenarios and which vessel segments and trade patterns are most likely to make OCCS viable first
The carbon value chain – beyond the ship factors are key such as port reception, transportation to storage facilities. Why access to offloading infrastructure is often the limiting factor, with lessons from the first end-to-end demonstrations of ship-captured CO₂