The European Maritime Safety Agency (EMSA) estimates that onboard carbon capture and storage systems (OCCS) could reduce shipping emissions on a Well-to-Wake (WtW) basis by between 29% and 44%. In its study published on February 13, 2026, the Agency goes even further, suggesting that when OCCS is combined with biofuels, lifecycle emission reductions could theoretically reach “up to 120%.”
These figures position onboard carbon capture as one of the most promising technological pathways for cutting maritime emissions. However, the opportunity comes with important trade-offs.
Emission Reductions vs. Energy Penalty
While OCCS can significantly curb CO₂ output, the process itself requires energy. According to EMSA’s analysis, the additional energy demand ranges from 9% to 30%, as ships must burn extra fuel to power the capture, conditioning, and storage of CO₂ onboard.
Beyond the energy penalty, the report also highlights environmental considerations that must be factored into system design and operation. These include solvent degradation and waste management, both of which can influence long-term sustainability performance and operational complexity.
In short, carbon capture reduces emissions — but it does not come without technical and environmental costs.
Technology Landscape: What’s Ready and What’s Emerging
EMSA’s study reviews the main carbon capture technologies currently under consideration for maritime use: pre-combustion, post-combustion, oxy-fuel combustion, and several emerging alternatives.
The most mature solution today is post-combustion capture via chemical absorption. Depending on configuration and operating conditions, capture rates between 30% and 90% have been demonstrated. The report identifies more than 15 pilot projects and installations using chemical absorption, underscoring its relative readiness for deployment.
Other technologies — such as membrane separation, cryogenic capture, and mineralization — are seen as promising but less technologically advanced at this stage.
Pre-combustion approaches, including LNG reforming or methane pyrolysis, introduce significantly higher technical complexity. These systems require deeper integration with propulsion architectures, particularly those involving hydrogen, making them more challenging to implement in the near term.
Economic Considerations: Retrofit vs. Newbuild
From a financial perspective, EMSA notes a clear distinction between retrofitting existing vessels and designing new ships prepared for OCCS integration.
Newbuild vessels configured from the outset for carbon capture generally show lower abatement costs compared to retrofit projects. Retrofitting is often penalized by integration challenges, higher fuel consumption impacts, and operational constraints.
Although capital expenditure remains substantial, the long-term competitiveness of OCCS will depend heavily on carbon pricing. As emission allowance costs rise and the technology matures, onboard capture could become increasingly attractive from a cost perspective, particularly over the medium to long term.
Infrastructure and Regulatory Gaps
Technological feasibility alone is not enough. Large-scale adoption of OCCS depends on the development of a functioning CCUS (Carbon Capture, Utilization and Storage) value chain.
This includes:
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Port infrastructure capable of handling liquefied CO₂ (LCO₂) discharge
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Transportation networks
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Permanent storage solutions
Without these elements in place, onboard capture risks becoming a stranded solution.
On the safety front, risk assessments indicate that OCCS can operate within acceptable thresholds, provided hazardous zones are properly classified and crews receive appropriate training. Nevertheless, EMSA points to regulatory gaps that will require coordinated international action. Without alignment, fragmented regulatory frameworks could create uncertainty and slow adoption.
A Transitional Technology with Strategic Implications
Onboard carbon capture is not a silver bullet, but it could play a meaningful role in shipping’s decarbonization pathway — particularly as a transitional solution for vessels operating on conventional fuels.
Its ultimate success will depend on three interconnected variables: energy efficiency penalties, carbon pricing dynamics, and the parallel build-out of CO₂ infrastructure. As these elements evolve, OCCS may shift from pilot-stage experimentation to a commercially viable decarbonization tool.
The coming years will determine whether onboard carbon capture becomes a niche technical option — or a structural component of maritime climate strategy.