Ship-to-ship CO2 transfer makes debut in China

June 27, 2025

In a world-first, Shanghai pulled off the first ship-to-ship transfer of liquid CO₂, marking a breakthrough in maritime decarbonization and turning ship emissions from waste into commodity.

The operation took place on June 19 at the Shengdong Terminal of Yangshan Deepwater Port, where the Panamanian-flagged EVER TOP, a 14,000-TEU container ship, offloaded captured carbon dioxide directly onto another vessel, the Dejin.

The container ship completed the transfer without using any pipes or port infrastructure—just open water and a direct handoff of captured emissions from one vessel to another.

Emission handoff at sea

This follows an earlier milestone in 2023, when EVER TOP completed the world’s first ship-to-shore transfer of captured CO₂ at the same port.

The vessel is equipped with an Onboard Carbon Capture and Storage (OCCS) system, which allows it to trap and store carbon dioxide from its own exhaust gases during voyages.

Developed by the Shanghai Marine Diesel Engine Research Institute, the OCCS system captures over 80 percent of a ship’s CO₂ emissions at 99.9 percent purity.

Retrofitting costs come in at around $10 million, which is less than half the cost of converting the same vessel to methanol or ammonia power.

“For scaled operations, ship-to-ship transfer offers clear advantages. It is significantly cheaper than land transport and much more efficient,” said Du Mingsai, project manager for the transfer operation. 

“A single CO2 carrier is able to handle dozens or even hundreds of times more volume than a tanker truck.”

Carbon becomes liquid currency

Crucially, the captured CO₂ can be sold for industrial use, with the potential to generate up to $8 million per year for a single ship.

However, offloading has been a longstanding challenge, as many buyers are located near smaller ports that cannot accommodate large container vessels. The ship-to-ship transfer offers a practical solution to this limitation.

 Transfers can now take place mid-voyage, without docking, using anchorages or sheltered sea lanes. The CO₂ can then be routed via smaller carriers to specialized terminals, closing the logistical loop.

From onboard storage to mobile transfer and reuse, the milestone gives Shanghai a full-chain ecosystem for maritime carbon capture.

It also positions the city as a global model for cutting shipping emissions and sets a new benchmark for the industry’s green transition.

With stricter emissions regulations from the International Maritime Organization, shipowners often face costly choices—either retrofitting vessels to run on methanol or investing in entirely new ammonia-fueled ships.

The OCCS system developed in Shanghai offers a more cost-effective alternative, cutting retrofitting expenses by half while extending vessel lifespan and turning captured emissions into a potential source of revenue.

The global shipping industry emits around 1 billion tons of CO₂ annually, making up nearly 3% of total global emissions, according to the International Maritime Organization (IMO).

Experts behind the project are already participating in a new IMO working group to help define carbon capture protocols for the entire shipping industry.