Zhejiang Power builds world’s first floating overhead transmission tower to boost deep-sea wind power delivery

State Grid Zhejiang Electric Power Company has developed the world's first floating overhead transmission tower, pioneering a brand-new technical solution for the long-distance delivery of deep-sea wind power.

In late September, the silvery transmission tower known as "Qinghai No 1" stably stood amid rolling waves off the coast of Taizhou in East China's Zhejiang province. As the world's first overhead transmission tower built on a floating platform, it marks a groundbreaking engineering practice in the global power industry. Deployed and towed from Kanmen Port in Yuhuan, Taizhou, in December 2025, the innovative floating tower has maintained stable operation at sea for more than 290 days.

Moving toward deep waters has become an irreversible trend for China's offshore wind power development. As nearshore wind resources approach saturation, Zhejiang is ramping up large-scale deep-sea wind power development, with a planned installed capacity of 28 million kilowatts. Nevertheless, power transmission remains the biggest bottleneck restricting deep-sea wind exploitation. Submarine cables face technical and economic limitations, with costs surging rapidly as transmission distance increases. Meanwhile, conventional fixed transmission towers are difficult to install on deep, silty seabeds. The lack of efficient and reliable power delivery has long hindered the transformation of deep-sea wind power plans into practical operational projects.

State Grid Zhejiang Power has cracked the dilemma with an innovative floating tower solution. The Qinghai No 1 tower is mounted on a semi-submersible floating platform and fixed to the seabed via a flexible mooring system. The structure allows slight swinging with ocean waves while sustaining normal power transmission. It also supports on-site wind-solar complementary self-power supply, significantly cutting offshore maintenance frequency and operational costs.

According to Gu Miaosong, project leader at the Economic and Technological Research Institute of State Grid Zhejiang Power, the floating transmission technology eliminates the need for large-scale underwater marine construction. Adopting an "onshore fabrication and offshore anchoring" model greatly shortens offshore construction windows. It offers a lightweight, replicable engineering pathway for power transmission from far-reaching offshore wind farms.

Harsh real marine conditions have fully validated the technology's reliability. From July to August 2026, three successive typhoons — Bavi, Dolphin and Saudel — swept directly across the operational sea area, bringing maximum wind force up to Level 14. Despite sustained violent wind and wave impacts, Qinghai No 1 remained intact with all operational parameters stable.

On-site monitoring shows the tower's swing angle stays within 1 to 2 degrees under normal sea conditions. Even during the direct strike of the Level 14 typhoon, its attitude remained within the designed safety range. The world's first field measurement data obtained near a typhoon center provides crucial references for the future engineering design and optimization of floating transmission technologies.

Preliminary calculations show that the floating overhead transmission technology can extend offshore wind power transmission distance from 70 kilometers to over 200 kilometers. In addition, the overall project cost can be reduced to approximately one-quarter of that of traditional submarine cable solutions, offering a cost-effective alternative for large-scale deep-sea wind power development.

From land-based networks to shallow seas and further to deep oceans, China's power transmission technologies continue advancing alongside the country's energy expansion. The stable long-term operation of Qinghai No 1 has fully verified the technical and engineering feasibility of floating overhead power transmission in complex real marine environments.