The Global Centre for Maritime Decarbonisation has successfully completed the world’s first maritime pilot of ship-to-ship transfer of onboard capture and storage (OCCS) of CO2, demonstrating the full value chain of OCCS in China. Shanghai Qiyao Environmental Technology conducted a ship-to-ship (STS) transfer of 25.44 metric tons (MT) of captured CO2 from the container vessel MV Ever Top to the receiving vessel Dejin 26.
The CO2 was subsequently offloaded from Dejin 26 to a tank truck at a jetty in Zhoushan, Zhejiang Province. Next the captured CO2 was taken to a joint venture plant between GreenOre and Baotou Steel in Inner Mongolia where the liquid CO2 (LCO2) was used in the production of low-carbon calcium carbonate, a key component in sustainable construction materials.
Onboard Carbon Capture and Storage (OCCS) systems allow a vessel to trap and store carbon from its own exhaust gasses during voyages. The ship-to-ship transfer is significant because, as stated by Lloyd’s Register, if vessels don’t offload the CO2 at regular intervals from the CCS process, the technology will cease to capture CO2 and the emissions will be released into the atmosphere. Ship-to-ship transfer means the vessel could offload the CO2 at sea without having to come into port.
This is especially important for larger vessels that can’t always dock in smaller ports where buyers for the CO2 are located. With ship-to-ship transfer, the vessels taking on the CO2 can then take it to buyers who may use it for a variety of products. Lloyd’s said converted carbon from the combustion process is in demand from greenhouse produce growers across Europe along with plastic and cement producers. Captured CO2 is also used in methanol, one of the most promising new low-emission fuels for shipping.
Developed by the Shanghai Marine Diesel Engine Research Institute, the company said the Ever Top’s OCCS system captures over 80% of a ship’s CO2 emissions at 99.9%. In 2023, Ever Top completed the world’s first ship-to-shore transfer of captured CO2 at the same port.
“We are proud to leverage our role as a neutral convener to bring together stakeholders from various sectors to address the technical and operational challenges of offloading and utilisation of CO2 captured onboard vessels,” said Professor Lynn Loo, CEO of GCMD. “This pilot marks a major step in demonstrating how onboard captured CO2 can be integrated into the broader circular economy. With a rigorous life cycle assessment underway, we are quantifying the climate impact across the entire value chain to show how OCCS can serve as a meaningful decarbonisation lever—when applied thoughtfully and transparently.”
The maritime industry contributes about 3% of global greenhouse gas (GHG) emissions, mostly from the burning of fossil fuels. With stricter emissions regulations from the International Maritime Organization and EU, shipowners often face costly choices—either retrofitting vessels to run on new fuels investing in entirely new ships.
Discharging carbon dioxide from vessels at scale does come with risks. CO2 is a pollutant in water as well as air. According to the International Tanker Owners Pollution Federation there were six large spills in 2024, over 700 tons each, and four medium spills of seven to 700 tons.
