Demonstration of Emissions Filtering and Carbon Capture for At-Berth Ships

Demonstration tests recently completed on vessels at the Prot of Long Beach, confirmed the ability to combine maritime emissions capture with carbon capture for at-berth vessels. The project combines the technology of STAX Engineering, a pioneer in maritime emissions capture and control based in California, and Seabound, a UK-headquartered leader in onboard carbon capture, offering what the companies call a comprehensive, cost-effective solution for the maritime industry.

Trails on the solution began in March 2025 and the companies report they conducted three iterations, including with Wallenius Wilhelmsen and NYK Line. The latest demonstration took place in Long Beach, yesterday, April 16, serving a RoRo vehicle carrier operated by Wallenius Wilhelmsen. The companies said the end-to-end modular solution has now cleared its final trial.

The combined system integrates STAX’s mobile emissions control unit—which removes 99 percent of particulate matter and 95 percent of Nox from the vessel’s exhaust—with Seabound’s carbon capture technology. Connecting directly to a vessel's exhaust pipe, STAX technology first removes criteria pollutants, turning the exhaust into purified gas. The gas is then directed through Seabound’s capture unit, isolating and storing up to 95 percent of carbon and 90 percent of sulfur before releasing the cleaned exhaust. The companies report that all results were independently verified by Yorke Engineering, an environmental consultancy.

“Our partnership demonstrates that effective, scalable emissions solutions are a reality that we can implement now,” said Alisha Fredriksson, co-founder and CEO of Seabound.

Since its launch in early 2024, STAX has established itself as the only emissions solution servicing all major vessel classes in California. To date, STAX reports it has provided a critical pathway to CARB (California Air Resources Board) compliance in five major ports, and captured more than 126 tons of pollutants. CARB is expanding its in-port emissions regulations to cover all classes of merchant ships.

STAX positions a barge alongside the vessel which places a cap on the funnel to capture emissions. The company reports it will deploy its eighth barge this month. STAX also recently announced $70 million in funding to fuel fleetwide carbon capture integration and international expansion this year.

Founded in late 2021, Seabound has demonstrated its onboard carbon capture technology. Seabound recently installed its system for onboard carbon capture system together with Lomar Shipping and Hapag Lloyd, successfully capturing CO2 at approximately 80 percent efficiency onboard a 3200 TEU container vessel. Seabound will be launching its first full-scale commercial carbon capture systems this year.

“Today marks a landmark moment in our journey toward a zero-emissions future, and it’s just the beginning of a global maritime emissions' solution,” said STAX CEO Mike Walker. “As we expand our carbon capture capabilities across the fleet, our inaugural partnership with Seabound has been instrumental, and we look forward to partnering again with ABP in the Port of Southampton.”

STAX and Seabound report they will continue their partnership in the UK's Port of Southampton. In March 2025, ABP accepted STAX and Seabound into its Energy Ventures Accelerator, a program designed to explore clean energy hardware startups to clean up ABP’s ports nationwide as it works toward Net Zero by 2040.