Breakthrough made in deep-sea clean energy

China has achieved a landmark breakthrough in the large-scale commercial development of deep-sea clean energy as the first batch of turbines for the Yangjiang Qingzhou Phase 5 and Phase 7 offshore wind project successfully connected to the power grid recently.

Featuring the world's highest voltage rating and largest transmission capacity for an offshore wind flexible direct current transmission system, the commissioning marks a decisive step forward in transmitting bulk green electricity across deep waters and long distances.

The project sets a new global benchmark for marine energy engineering, said its operator China Three Gorges Corp.

The massive clean power complex is situated in waters south of Yangxi county in Yangjiang, Guangdong province. The project comprises 163 wind turbines with a total installed capacity of 2 gigawatts. Operating at a site roughly 70 kilometers offshore with water depths exceeding 50 meters, the facility must withstand complex and volatile sea conditions.

The project employs an advanced 500-kilovolt flexible DC transmission architecture. Electricity generated by the turbines is channeled through 66-kV inter-array cables into the "Heart of Sea Breeze" — the world's largest offshore converter station — where it is stepped up and converted from alternating current into direct current.

The power is then transmitted directly to an onshore central control station via 500-kV subsea DC cables, representing the first commercial deployment of such high-voltage DC marine cables worldwide, it said.

Industry experts believe that beyond structural milestones, the megaproject showcases China's escalating industrial self-reliance, achieving significant domestic manufacturing breakthroughs in structural steel foundations, high-power turbine units, high-voltage submarine cables and advanced power electronics.

"Since completing turbine installations in early August, our engineering team has overcome formidable marine challenges, including severe swells, dense salt-spray corrosion and frequent typhoons," said Gu Pengcheng, an engineer at CTG's Yangjiang division. "Successfully synchronizing this initial batch of turbines lays a solid foundation for delivering full-capacity commercial operations as scheduled."

Once fully operational, the 2-GW complex is expected to supply approximately 6 billion kilowatt-hours of clean electricity annually to the Guangdong-Hong Kong-Macao Greater Bay Area — equivalent to offsetting nearly 5 million metric tons of carbon dioxide emissions each year.

The breakthrough arrives as China's clean energy expansion accelerates toward marine frontiers. Energy analysts note that driven by continuous engineering leaps, offshore wind and deep-sea development has become essential engines for safeguarding national energy security while decarbonizing load centers along the economically vibrant eastern seaboard.

This momentum is reflected in broader macroeconomic trends. According to data from the Ministry of Natural Resources, China's gross ocean product reached 5.5 trillion yuan ($820 billion) in the first half of the year, expanding 5.1 percent year-on-year.

Outpacing overall GDP growth by 0.4 percentage point, the marine economy accounted for 7.9 percent of total GDP, demonstrating the structural strength of coastal industries.

Coastal industrial powerhouses such as provinces of Guangdong, Jiangsu, Shandong and Fujian have cultivated advanced manufacturing clusters spanning turbine fabrication, subsea cabling, installation and offshore maintenance. This industrial foundation has enabled specialized enterprises to overcome bottlenecks in high-end components, establishing an autonomous and resilient deep-sea supply chain.

According to industry consultancy BloombergNEF, global wind capacity additions hit an all-time high of 169 GW last year.

Wind installations over the past decade are increasingly concentrated in China, with stable long-term policy support, it said.