CATL, COSL partner to electrify offshore support vessels

Gasgoo Munich- In mid-March, CATL signed a cooperation framework agreement with the vessel division of China Oilfield Services Limited ("COSL"), setting the stage for joint development of electrified offshore support vessels.

Image source: CATL

According to a post CATL issued on March 28 via its WeChat account, the partnership will focus on designing battery-powered and hybrid solutions tailored to offshore engineering and transport operations, with the aim of improving safety while reducing emissions across maritime oilfield logistics.

The collaboration builds on earlier retrofit projects in which CATL supported COSL in upgrading two offshore support vessels—“Haiyang Shiyou 545” and “Haiyang Shiyou 55” —with LNG-battery hybrid propulsion systems. These vessels integrate energy storage with cleaner fuel sources, using load-shifting strategies to optimize performance by charging during low-demand periods and discharging at peak loads.

After a year in operation, the Haiyang Shiyou 545 has demonstrated notable efficiency gains, cutting fuel consumption by around 170 tonnes and reducing carbon emissions by more than 500 tonnes compared with conventional fuel-powered ships. The hybrid system has also lowered engine runtime significantly, contributing to both cost savings and improved operational stability.

The new agreement signals CATL's deeper push into maritime electrification, extending its battery expertise beyond road transport into offshore energy applications. For COSL, the move aligns with broader efforts to decarbonize oilfield services while maintaining operational efficiency. Together, the companies aim to accelerate the adoption of low-carbon propulsion technologies in offshore fleets, positioning electrified vessels as a viable pathway toward more sustainable marine operations.