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Horizons article 01 June 2023

Carbon capture’s role in maritime’s energy transition

  • Maritime energy transition
  • Carbon Capture & Storage
Issue 64
Carbon molecules being caught in a net graphic.

Carbon capture techniques can allow traditional fuels to play a significant role in shipping’s decarbonisation, turning carbon-intense fuels into a transitional energy source.

Sean van der Post

Sean van der Post

Global Offshore Business Director, Lloyd's Register

Shipping is responsible for 2.5% of the world’s total greenhouse gas emissions. Technology to reduce the impact of LNG and diesel vessels emissions is crucial if the industry is to achieve the IMO mandated target of a 50% cut in greenhouse gas emissions from the global fleet by 2050 compared with 2008 levels.

While alternative low and zero carbon fuels are gaining traction, the industry, supply chain and technology readiness is not there for an overnight transition. Carbon capture and storage (CCS), where fossil fuel emissions are captured before they enter the atmosphere, offers a solution using technology that’s available now, in the run-up to the adoption of green fuels.

But the positioning of CCS as a near-term transitional solution could be a problem for investors, who may question whether investment will be worth it, if the technology is only used for a short period. The stark reality, however, is that ships must comply with intensifying carbon regulations over a long term. There will be ships running on diesel or LNG for decades to come, and CCS will allow them to remain operational in alignment with these regulations.

What is CCS?

Carbon Capture and Storage (CCS) systems are technologies that can capture CO2 from a vessel’s exhaust for future use or safe storage.  

Shoreside CCS involves the capture of carbon emissions from industrial processes, such as steel and cement production, or from the burning of fossil fuels in power generation. This carbon is then transported from where it was produced, via ship or in a pipeline, and stored deep underground either in geological formations or derelict excavations.  

Traditionally, CCS has been focused on onshore applications, but the same technology can be applied to reduce the carbon footprint of the global fleet operating on fossil fuels. We have already seen some progress, including Value Maritime’s Filtree system, which has been fitted on Eastern Pacific Shipping’s carriers Pacific Cobalt and Pacific Gold, making them the largest ocean-going vessels to be fitted with carbon capture technology. 

The three main types of CO2 capture systems for the maritime sector are post-combustion, pre-combustion, and oxyfuel combustion. Oxy-fuel and pre-combustion remove carbon from the fuel before use. These  systems typically require complete engine redesign, because they need to be integrated into a fuel supply and power generation system of a vessel. They are costly and time-consuing, so may not be suitable for the shipping industry.  

The post-combustion process, however, captures CO2 from flue gas produced after combustion and can be added to traditional engine design without the need for large changes. Value Maritime’s Filtree is an example of this method, making CCS technology less costly and more attractive for ship owners.  

Carbon molecules balancing on a white scale.
Carbon dynamite graphic

CO2 captured, what next?  

Once carbon is captured by CCS technology, there are a number of ways to store and use the CO2. Vessels are limited by space and power, making  storage and liquification an issue. At present vessels need to make frequent stops to offload the CO2 from the CCS process. If they don’t, the technology will cease to capture CO2. Although the ship’s engine will not be affected, all the vessel’s emissions will be released into the atmosphere.  

The transportation and onward usage of captured carbon provides an interesting scenario. As a commodity, CO2 will likely have a negative value - not unlike hazardous waste. But it could be a crucial component of establishing maritime’s circular economy.  

Converted carbon from the combustion process is in demand from greenhouse produce growers across Europe along with plastic and cement production.  Perhaps the most interesting possibility is the production of green methanol and renewable electricity from CO2. This further underlines CCS technology’s credentials as an intermediate tool for maritime’s decarbonisation journey.  

There are, of course, safety issues associated with the discharge of carbon dioxide from vessels at scale which would need to be carefully managed. The industry does have experience of offloading other hazardous materials from vessels. Updating mandatory regulations for the handling of CO2 and other hazardous materials will be the key to ensuring best practise when it comes to the lifecycle of captured carbon.  

Value Maritime’s Filtree CCS system  

In 2022, LR gave approval in principle for Value Maritime’s Filtree carbon capture system. It is fitted to two Eastern Pacific Shipping carriers. They are the largest ocean-going vessels to be fitted with carbon capture technology.  

The Dutch maritime engineering firm have adopted a ‘plug and play’ solution. The compact Filtree system is connected directly to the exhaust,  and is designed for small to medium sized vessels. The technology allows vessels to capture up to 40% of CO2 emissions, with the potential of exceeding 90% in the future. 

The unique technology does not liquefy the gas – instead, it uses a CO2 absorber (monoethanolamine). The solvent mixture is stored in tank containers for simple offloading in port, or in onboard tanks for pumping ashore. Value Maritime then takes responsibility for the next stage, including extracting and liquefying the CO2 which can be used for a wide variety of purposes such as fertiliser or biodiesel production. 

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