On August 20 this year, the ±800 kV ultra-high voltage direct current (UHVDC) power transmission project from Ningxia to Hunan (hereinafter referred to as the “Ningxia-Hunan Project”) was officially fully commissioned and began delivering electricity. Functioning as a massive green “power bank,” this project has a rated maximum transmission capacity of 8 million kilowatts and can transmit 36 to 40 billion kilowatt-hours of electricity to Hunan annually. Notably, new energy sources account for no less than 50% of this transmitted power.
the Hengyang ±800-kV converter station in Hengnan County, Hengyang City, Hunan Province. Photo by Yang Juzheng
The Ningxia-Hunan Project is China’s first approved UHVDC transmission channel primarily designed to deliver new energy from massive wind and photovoltaic power bases located in desert, Gobi, and barren areas. The project starts at the Zhongning Converter Station in Zhongning County, Ningxia, and ends at the Hengyang Converter Station in Hengnan County, Hunan, passing through six provincial-level regions: Ningxia, Gansu, Shaanxi, Chongqing, Hubei, and Hunan, covering a total transmission distance of 1,616 kilometers.
Construction on the project officially commenced in June 2023. It includes supporting power generation facilities with a total installed capacity of 17.64 million kilowatts, of which 13 million kilowatts come from new energy sources (4 million kilowatts from wind power and 9 million kilowatts from photovoltaic power generation). The proportion of new energy in the project’s total installed capacity exceeds 70%, setting a new record among similar projects.
It is reported that by traveling along this “electricity superhighway,” the abundant green electricity generated in Ningxia can be transmitted to Hunan in just 0.0054 seconds. Annually, this can replace approximately 6 million tons of standard coal in Hunan and reduce carbon dioxide emissions by about 18 million tons. This emission reduction is equivalent to the annual carbon absorption of 1 billion trees.
On June 19, the Ningxia-Hunan Project completed low-voltage bipolar commissioning, establishing a transmission capacity of 4 million kilowatts before the peak summer electricity consumption period. Throughout the entire summer, the project’s average transmission power reached nearly one-tenth of Hunan’s total electricity load, with a cumulative transmitted electricity volume exceeding 3.5 billion kilowatt-hours, playing a crucial role in ensuring Hunan’s power supply.
It is reported that to address safety risks associated with manual excavation for the large-diameter and deeply-buried foundations required for the UHVDC line, 95% of the 1,355 foundation pile locations in the Hunan section were constructed using mechanized methods. For the 25 ecologically sensitive areas and 11 water source protection zones that the project crosses or traverses, efforts were made to minimize the number of erected towers within the boundaries of these protected areas. (By Zhang Xueying)