China State Shipbuilding Corporation (CSSC) has announced a shipbuilding agreement covering four tri-fuel ships.

CSSC subsidiaries Qingdao Beihai Shipbuilding Heavy Industry Co., Ltd. (Beihai Shipbuilding) and China Shipbuilding Trading Co., Ltd. (CSTC) signed a contract with South Korea’s Polaris Shipping for four 210,000-tonne tri-fuel ore carriers.

The vessels form part of Beihai Shipbuilding's independently developed Sirius series. The ships are designed around a tri-fuel propulsion arrangement combining ethanol, methanol, and fuel oil, and are said to accommodate future conversion to ammonia or LNG.

According to CSSC, using ethanol as the primary fuel will reduce greenhouse gas emissions by approximately 90% compared with traditional heavy fuel oil. The vessels are also equipped with a wind-assisted propulsion system using rotor sails, alongside frequency conversion technology, high-voltage shore power, and shaft-driven generators, all intended to reduce operational carbon emissions.

The cargo hold structure has been designed to accommodate Category A cargoes that may liquefy under the International Maritime Solid Bulk Cargoes Code (IMSBC Code), and a structural stress monitoring system has been integrated to support the vessel’s structural integrity during voyages.