1500TEU Carbon Capture
Wärtsilä Exhaust Treatment

Onboard carbon capture and storage

The international maritime industry is exploring various solutions to rapidly reduce Greenhouse Gas (GHG) emissions and meet global climate goals. The focus is now on technology that can reduce GHG emissions from ships in the shortest possible timeframe, and preferably starting well before 2030.

Tackling CO2 with exhaust gas abatement technology

As the leading manufacturer of exhaust gas abatement technologies, Wärtsilä Exhaust Treatment already enables ship owners and operators to reduce their SOx, NOx and Particulate Matter (PM) emissions. Utilising this long-standing experience and in-depth knowledge of abatement technologies, we are developing the industry’s first onboard carbon capture and storage (CCS) technology.

While the industry waits for future fuels to be developed and scaled up – requiring sufficient renewable energy sources to produce carbon-neutral fuels and the build out of extensive supply chain infrastructure to ensure availability worldwide – CCS provides an immediate opportunity for sustainable shipping.

Onboard CCS is also dependent on infrastructure but can integrate with existing solutions that are already in place for land-based CCUS projects.

Control room

Onboard carbon capture is a solution with immediate potential to enable marine decarbonisation for both existing and newbuild vessels.

Sigurd Jenssen, Director of Wärtsilä Exhaust Treatment

CCS lift-off

To succeed in reducing maritime CO2 emissions by 70% by 2050, the target set by the International Maritime Organization (IMO), the industry will be dependent on several technologies, most of which are currently under development.

Wärtsilä Exhaust Treatment is taking a central role in developing CCS technologies. From our years of experience in SOx scrubbing and installing technologies that tackle pollutants at the point of exhaust, we are uniquely positioned to pioneer CCS in maritime and unlock immediate decarbonisation benefits for owners and operators.

Engineer in lab

CCS-ready scrubbers

To futureproof vessels for compliance with current and expected environmental regulations while ensuring profitability and efficiency, we are providing ship owners with CCS-ready scrubbers. The solution builds on a standard scrubber installation platform by conducting the groundwork for future CCS integration.

As a technology platform, scrubbers act as a springboard for other environmental abatement technologies to support marine decarbonisation. In a CCS-ready configuration, the scrubber will not only tackle SOx emissions but can also be built upon to tackle PM, NOx and the filtration of microplastics. By using a scrubber as the first building block, modification requirements of the tower for CCS integration are minimised and can be accounted for in the design phase.

Ship owners who invest in a scrubber today are laying the foundations to easily upgrade their systems with additional technologies to improve maritime sustainability, ensure compliance and futureproof their assets.

Service engineer inspecting scrubber

A scrubber will serve as excellent preconditioning of the exhaust gas, optimising CCS performance in addition to its inherent environmental benefits.

Stian Aakre, General Manager, Technical & R&D

Engineering principles

At Wärtsilä Exhaust Treatment’s world-class research centre and test facility in Moss, Norway, we can emulate vessel installations of exhaust treatment technologies in a variety of configurations and set ups.

The first challenge for our R&D team was to demonstrate the capture of CO2 into an amine-based solvent. Amine is a liquid made of organic nitrogen base, and has been used for the stripping of H2S in the oil and gas industry since the 1980s.

The principle behind the solvent is to capture CO2 in a spray tower. The CO2 saturated solvent is then transported to a separate column where the captured CO2 is stripped off. By regenerating the solvent with heat, the CO2 is released from the solvent, liquefied and stored; and the solvent is re-used in the capture process loop.

The test installation was initially dimensioned to achieve a capture rate of at least 70% of CO2 from the exhaust gas. We believe that this is an initial optimum target, enabling us to balance commercial viability with regulatory targets. Our testing shows that the capture rate can likely reach 80% with a solvent optimised for marine engine exhaust gas.

Numerous configurations

Flexibility and modularity are key, which is why Wärtsilä Exhaust Treatment offers different configurations for CCS units and the technology can be suitable for all ship types.

This is possible because the SOx scrubber acts as the first building block for CCS. By providing scrubber-enabled CCS technologies, ship owners and operators will be empowered to reduce emissions in the short and medium term before low-carbon fuels emerge.

Meanwhile, onboard storage of the captured CO2 can be achieved in different ways – for example by using deck tanks or container tanks. All of this is explained and planned for by our experts during the design phase of a CCS-ready scrubber.

Engineers with laptop

World-first maritime CCS pilot leads the way for product launch in 2025

The next stage of this ambitious journey is to pilot the CCS system on a ship of a representative size, age, and complexity. During 2023, the system will be installed on the 21k-cbm ethylene carrier Clipper Eos for full scale testing and optimisation. The ship is owned and operated by Norwegian Solvang Shipping. This test will prove the technical viability of the system, and provide vital learnings on crew training and handling in-operation. The trial will also enable us to test how the technology can integrate with land-based CCS infrastructure.

Our CCS pilot unit aims to deliver a carbon capture rate of 70% of CO2 emissions, which will ensure compliance with the IMO’s decarbonisation targets, as well as Solvang’s ambition to decarbonise their deep-sea fleet.

With a successful CCS pilot, further commercialisation and scaling will follow. Our CCS solution will be on the market in 2025, allowing CO2 capture on ships to have a major impact well ahead of 2030.

Clipper EOS

IMO’s targets build momentum for CCS efforts

In 2018, the IMO adopted its initial GHG strategy to reduce CO2 emissions per transport work, targeting a cut in vessel carbon intensity by 40% by 2030, and a reduction in total annual GHG emissions from international shipping by at least 50% by 2050, compared to 2008.

This strategy is now under revision and the new strategy is expected to require more rapid emission reductions as well as to contain another intermediate milestone in 2040. The revised strategy is expected to be presented at MEPC 80 in July 2023.

As so-called short-term measures (leading up to the first milestone in 2030), IMO is implementing EEXI (Energy Efficiency Existing Ship Index) and CII(Carbon Intensity Indicator). These regulations will require all vessels to calculate their EEXI to improve their energy efficiency, in addition to collect data for their annual operational CII rating. The regulations enter into force from January 2023, making 2024 the first year for reporting and rating.

Developing the framework and regulation for decarbonising the maritime industry is a continuous process within IMO and during MEPC 79 in November 2022, important steps were taken towards adopting a life cycle approach to ship-generated emissions. This means including the entire value chain of the energy source; “from well to wake”. This takes into account energy related to production and logistics of the fuel in addition to the emissions created by combustion onboard. From a global perspective, this is very important and ensures better utilization of available energy and technologies.

In this context, IMO also started discussing how onboard carbon capture solutions and their related carbon accounting principles can be implemented in the EEXI and CII regulations. Several flag states, such as Korea, Japan, Liberia and Norway, have submitted papers to MEPC with proposed approaches and solutions. The main discussion of this important topic was deferred to MEPC 80 in July 2023 to make sure the outcome is properly aligned with the ongoing development work of the overall strategy and the life cycle approaches.

EEXI is a one-off exercise for vessels to document and calculate their energy efficiency. By some called "ticket to play".

CII measures how energy efficiently a vessel transports goods and or passengers and is measured in grams of CO2 emitted per cargo-carrying capacity and nautical mile. Ships will get a CII rating of their energy efficiency of A, B, C, D, or E, where A is the best. To ensure industry improvement, the rating baseline is lowered each year with 2019 as reference:


With environmental pressure and stricter regulations, we must embrace technology to tackle shipping’s key sustainability issues.

Sigurd Jenssen, Director of Wärtsilä Exhaust Treatment

EU and other carbon reducing efforts

As part its Green Deal, the European Union has put forward a plan to further reduce emissions by at least 55% by 2030. By 2050, Europe aims to become the world’s first climate-neutral continent. Under the Fit for 55 program, EU has decided to include shipping in the ETS (Emissions Trading Scheme). This will be done through a three year phase-in, starting from 2024 with 40% of verified emissions. From 2026, allowances for 100% of verified emissions must be surrendered. The same year, smaller vessels (>400 gross tonnage) as well as non-CO2 emissions (methane and N2O) will be included in the scheme. It is expected that other important regions worldwide will implement similar fiscal incentives for emission reductions.

Leading classification societies are working to provide regulations and guidelines for owners and operators to navigate through the challenging waters of decarbonising possibilities and technologies. DNV published in their 2021 edition of the “Maritime Forecast to 2050” report a recognition of onboard carbon capture and temporary storage and suggested this as a viable option for decarbonising deep-sea vessels towards 2050. ABS released in December 2022 their first set of regulations for installation of onboard carbon capture systems. Bureau Veritas is known to do the same in 2023.

Contact us

Please email us at karl-einar.jensen@wartsila.com. We will respond as soon as possible. For CCS in combination with an existing scrubber installation, provide details to identify the ship and the equipment.

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