Features | 27.06.2025 | 3 min read
HVDC technologies from Hitachi Energy contribute to the world's first ultra-high voltage flexible direct current transmission line.
Hitachi Energy will provide High-Voltage Direct Current (HVDC) equipment for the Gansu-Zhejiang ±800 kV Ultra High Voltage Direct Current (UHVDC) Transmission project, designed and built by the State Grid Corporation of China (SGCC). This project will facilitate the development and transmission of energy from renewable energy bases in China’s Gobi Desert and other arid regions, while meeting the increased power demand driven by economic development in the Yangtze River Delta region.
As energy transition advances, China’s renewable energy industry is growing rapidly. According to the International Energy Agency (IEA), China is forecasted to be home to half of all renewable energy capacity installed worldwide by 2030.1 UHVDC transmission projects are crucial power infrastructures that will improve China’s energy structure and large-scale power transmission. In 2023, the share of renewable energy transmitted via national UHVDC lines had already surpassed 55 percent.2
The transmission project starts from northwest China’s Gansu province and extends to southeast China’s Zhejiang province, spanning approximately 2,370 km. Upon its operation in 2026, the project will deliver approximately 36 billion kilowatt-hours (kWh) of electricity annually to Zhejiang, which regularly faces power shortages. This is equivalent to the annual power consumption of around 33.7 million people in China. With more than 50 percent of the power sourced from renewable energy, the project will effectively optimize Zhejiang’s energy mix.
Furthermore, the construction of the UHVDC project will improve the utilization of renewable energy in Gansu Province, which is home to vast deserts, including the Gobi Desert, and barren lands rich in wind and solar resources, making solar and wind energy the dominant power sources in the province. As the world's first UHVDC project to adopt VSC-HVDC technology at both ends, the link aims to increase the proportion of renewables integrated while improving transmission flexibility and control. It is expected to enable the consumption of over 21.2 billion kWh of renewable energy electricity generated in Gansu upon completion.
Hitachi Energy will provide key technologies for the flexible transmission project, including converter transformers, power semiconductors, and Dry DC-link capacitors manufactured in China, Switzerland, and Sweden. The technologies will boost transmission capacity while ensuring the reliable, efficient, and smooth transmission and distribution of electricity over long-distance links.
“The development of UHVDC projects will help strengthen China’s power grid, meet surging electricity demand, and provide strong support for renewable energy integration and utilization. We are glad to participate in the Gansu–Zhejiang UHVDC project, the world’s first ultra-high voltage flexible direct current transmission line.
We look forward to closely working with our customers and partners, driving the development of VSC HVDC technology in China with our pioneering technologies, contributing to China’s energy transition.”
Hitachi Energy pioneered commercial HVDC technology over 70 years ago and delivered more than half of the world’s HVDC projects. The company enabled the integration of over 150 gigawatts of HVDC links worldwide into the power system. It has participated in over 50 HVDC projects in China, with around half of these being UHVDC power projects.
