Seabound is a climate tech startup aiming to decarbonize the shipping industry with a compact, retrofittable carbon capture unit that traps up to 78% of CO₂ emissions from cargo ships. The maritime industry, responsible for about 3% of global greenhouse gas emissions—more than aviation—faces significant challenges in cutting emissions due to the massive size and energy demands of vessels. While long-term solutions focus on sustainable fuels and hydrogen, Seabound offers an immediate, scalable alternative to reduce pollution on existing ships.
In partnership with Lomarlabs, a subsidiary of Lomar Shipping, Seabound launched its pilot project in 2023 under the U.K. Department for Transport’s Clean Maritime Demonstration Competition. The system, inspired by industrial carbon-capture techniques, uses quicklime (calcium oxide) to bind with CO₂ in ship exhausts, converting it into stable calcium carbonate (limestone). The limestone can be offloaded at port and either sold or processed to recover the quicklime for reuse. This setup allows for minimal onboard space usage and is adaptable to existing vessels, making it a compelling retrofit option.
Initial tests demonstrated promising results: 78% carbon capture efficiency and over 90% sulfur capture. The company’s technology was deployed during a three-week voyage through the Suez Canal aboard a 3,200-container ship, where it captured about a tonne of CO₂ daily. The next-generation prototype is designed to fit inside standard 20-foot shipping containers, allowing the carbon capture units to travel alongside regular cargo. Ships can increase or decrease capture capacity during journeys by swapping limestone-filled containers with fresh quicklime ones at ports, offering flexibility for shipping companies.
To further reduce environmental impact, efforts are underway to produce quicklime using renewable energy, with kilns powered by green electricity and integrated carbon capture. Seabound is pursuing these sustainable sourcing methods to enhance the eco-friendliness of its solution.
Despite its innovation, Seabound’s approach is not without criticism. Environmental groups caution that short-term retrofits should not be seen as a reason to delay transitioning to zero-emission alternatives. They argue that relying on carbon capture could prolong the use of fossil fuels in shipping. However, co-founders Alisha Fredriksson and Roujia Wen maintain that their technology is a practical mid-term bridge. It can help meet tightening regulations while governments and companies scale up long-term solutions like hydrogen and green fuels.
As of 2025, the company is expanding its trials and refining its product. Each carbon capture unit costs tens of thousands of pounds, and shipping companies are showing increasing interest as they prepare for stricter emissions rules. Seabound’s goal is to have its technology deployed on thousands of vessels, serving as a critical transitional tool in the global effort to decarbonize maritime transport.
In the broader context, carbon capture should be seen as a complementary measure—not a substitute for comprehensive climate action. While Seabound’s innovation helps mitigate emissions now, the future of sustainable shipping depends on industry-wide shifts to renewable energy and next-generation propulsion systems.