China's First 2 GW Offshore HVDC Converter Platform Installed

COSCO Shipping Specialized Carriers has completed the transport and float-over installation of the offshore converter platform for the Three Gorges Qingzhou V & VII offshore wind project off Yangjiang City, Guangdong Province, marking the first installation of a 2 GW offshore high-voltage direct current (HVDC) transmission system anywhere in the world.

The platform, named Hai Feng Zhi Xin ("Heart of the Sea Wind"), was built by Shanghai Zhenhua Heavy Industries Co., Ltd. (ZPMC) using a modular construction approach that enabled simultaneous onshore assembly, equipment integration, and installation activities. The structure measures 85.5 metres long, 82.5 metres wide and 44 metres high, and weighs approximately 25,000 tonnes, placing it among the largest offshore structures ever installed in the offshore wind sector. The platform operates at ±500 kV and houses the HVDC conversion equipment required to transmit electricity from 163 offshore wind turbines to the onshore grid via ±525 kV DC subsea cables — the first offshore wind project to use cables of this voltage rating for long-distance renewable power transmission.

ZPMC has stated that the project establishes six industry records, including the world's first offshore converter station with a single-unit transmission capacity of 2,000 MW, the world's highest-voltage offshore wind flexible direct-current transmission system, and the first centralised offshore wind flexible DC transmission project to combine AC and DC technologies within a single system. The platform is designed for unmanned operation, with remote monitoring and intelligent maintenance systems, and incorporates electrical, ventilation and fire-control systems rated for high-salt, high-humidity offshore conditions.

The platform departed Nantong, Jiangsu Province, on 27 May 2026, travelling approximately 1,090 nautical miles to its installation site. COSCO deployed its DP2-class, 65,000-deadweight-tonne semi-submersible vessel Xiang Tai Kou for both the load-out and float-over installation phases. Prior to the voyage, the vessel completed the world's first skid-on loading of a 2,000 MW offshore converter platform — a stern-to operation with the structure at approximately 28,000 tonnes at that stage, making it the heaviest such skid-on load ever accomplished globally. The Xiang Tai Kou's advanced ballasting system and dynamic positioning capability enabled precise positioning and controlled submergence during the float-over installation offshore Yangjiang.

The Qingzhou V & VII project, developed by China Three Gorges, has a combined installed capacity of 2 GW and is expected to generate approximately 7.7 billion kilowatt-hours of electricity annually once fully commissioned — sufficient to supply more than one million households — and to reduce carbon dioxide emissions by approximately 6.3 million tonnes per year. The project represents China's move into ultra-high-voltage direct-current transmission for offshore wind, addressing the increased transmission losses associated with AC power delivery over the longer subsea cable routes required by deep-water and farshore wind developments.

COSCO has also confirmed that a new 70,000-tonne-class semi-submersible vessel is currently under construction, intended to support the installation of larger and more technically demanding offshore energy structures in future projects.