COSCO Shipping Specialized Carriers has completed the transport and float-over installation of an offshore converter platform for the Qingzhou V & VII offshore wind project, a key milestone in what the company described as the world's first 2 GW offshore high voltage direct current (HVDC) transmission system.
The converter platform, weighing about 25,000 tonnes, is among the largest offshore structures installed for the offshore wind industry and was transported and installed using an integrated heavy transport and offshore installation solution provided by COSCO.
The operation was carried out by the DP2-class 65,000-deadweight-ton semi-submersible vessel Xiang Tai Kou, which is designed to function both as a heavy transport carrier and an offshore installation vessel.
COSCO said the vessel's dynamic positioning and advanced ballasting systems enabled accurate positioning of the platform and controlled submergence during the float-over installation.
The company said the project required precise coordination and real-time operational control throughout both the transportation and installation phases.
The Qingzhou V & VII offshore wind project is expected to generate approximately 7.7 billion kilowatt-hours of electricity annually when fully commissioned, enough to supply more than one million households. The project is also expected to reduce carbon emissions by about 6.3 million tonnes per year.
COSCO said the successful installation demonstrates the capability of the Xiang Tai Kou to support the deployment of next-generation offshore infrastructure, including HVDC converter stations, oil and gas topsides and other large-scale offshore energy assets.
The company added that a new 70,000-tonne-class semi-submersible vessel is currently under construction and is expected to enter service in the future, expanding its capacity to support larger and more complex offshore installation projects.