The race is on to decarbonise shipping, a hard-to-abate industry in which it is extremely difficult to cut emissions. Over 50,000 cargo ships are at sea at any moment, and these ships produce around 3 percent of global greenhouse gas emissions, which is even more than aviation, showing the dire need to clean up the industry. The long-term focus is on developing sustainable fuels, hydrogen fuel cells, or batteries big enough to power these giant vessels. However, one company believes it may have a short-term solution for reducing emissions as it rolls out its carbon-capture technology on board ships.
In 2023, the climate tech start-up Seabound partnered with Lomarlabs, a subsidiary of UK-based shipowner Lomar Shipping, to trial a new technology that it hoped would capture carbon emissions to help decarbonise its shipping activities. The pilot project was part of the U.K. Department for Transport’s 2022 Clean Maritime Demonstration Competition Round 3, which allocated $82 million to 19 flagship projects.
Seabound’s compact carbon capture device can be retrofitted into a ship’s engine exhaust at the funnel, giving it the potential to be used on a wide range of preexisting vessels. The technology takes up little space on board but can make a big difference. Carbon dioxide, which comes from the diesel that is burnt to power the vessel, chemically reacts with little calcium oxide (quicklime) pebbles, which are used to convert the CO2 into calcium carbonate, or limestone, to lock it in and stop it being released into the atmosphere. The pebbles can be stored easily on the ship until it returns to port, where the limestone is offloaded to be sold in its pure form or to be reseparated into quicklime and CO2 for the quicklime to be reused on other vessels.
Co-founders Alisha Fredriksson and Roujia Wen took the idea from the quicklime-based carbon-capture technology often used at industrial plants. They developed a prototype that helped them raise $4 million in funding from investors who were looking for a way to decarbonise shipping.
During pilot projects, Seabound was able to improve the rate of emissions capture to 78 percent carbon capture efficiency and over 90 percent sulphur capture. The team hoped to improve this to up to 95 percent emission capture. Seabound’s prototype captured around one tonne of carbon dioxide emissions a day during the test.
In 2025, the project is still advancing. Since the initial tests, Seabound has advanced its prototypes and tested its technology in Turkish shipyards, on the deck of a 3,200-container ship, and a three-week trip down the Suez Canal. The company’s new prototype is being developed to the dimensions of a standard 20-foot shipping container, meaning that it will be able to slot in with the cargo on deck.
Several containers with quicklime will be stacked alongside regular cargo so that the ship can incrementally increase carbon capture as the journey progresses, as containers holding limestone can be traded out for containers of fresh quicklime. This means shipping companies can manage the level of carbon capture during a ship’s journey by purchasing and using more or fewer quicklime containers.
To make the project even cleaner, companies are working on producing quicklime using kilns heated with renewable energy or incorporating carbon capture technology into manufacturing operations. Seabound hopes to source this green quicklime for future projects to make its operations more sustainable.
However, some environmental groups are concerned that incorporating carbon capture technology into vessels could deter the maritime sector from investing in long-term decarbonisation options. Blánaid Sheeran at Opportunity Green said, “The potential for short-term use of carbon-capture retrofits on existing vessels should not become a justification to extend the lifespan of fossil fuels or delay the shift to truly sustainable alternatives.”
However, Fredriksson and Wen believe that their technology can be used in the mid-term, while governments increase shipping regulations and invest in long-term decarbonisation technologies. As stricter regulations on maritime emissions are introduced, the founders plan to roll out more containers to help decarbonise.
The next challenge for Seabourne is to scale up operations. Each of the company’s quicklime units is priced at tens of thousands of pounds. Nevertheless, Fredriksson and Wen believe the units are cost-effective, and they are seeing increasing interest from shipping companies that are looking to decarbonise. The founders hope their technology will eventually be used on thousands of ships all over the world.
While innovative carbon capture technology cannot be used as a preventative method for carbon emissions, it may be useful in helping prevent large quantities of CO2 from being released into the atmosphere as a mid-term solution. Meanwhile, governments must introduce stricter regulations on the maritime sector and shipping companies should invest in research and development into sustainable fuels and other long-term solutions.
By Felicity Bradstock for Oilprice.com