Why are these provinces forming partnerships?

Recently, the back-to-back interconnection projects between Chongqing and Guizhou, Hunan and Guangdong, and Fujian and Jiangxi have successively started construction.

On December 27, the Hunan-Guangdong back-to-back interconnection project officially kicked off in Chenzhou, Hunan. After the project is put into operation, it will achieve flexible mutual support between the State Grid and the China Southern Power Grid, promote the optimized allocation of power resources in Hunan and Guangdong provinces, and effectively enhance Hunan's stable power supply capacity.

Previously, on December 26, the Chongqing-Guizhou back-to-back interconnection project started construction in Chongqing. After the project is completed, it will strengthen the interconnection between the State Grid and the China Southern Power Grid and assist in the power mutual support between Chongqing and Guizhou.

On December 25, the Fujian-Jiangxi back-to-back interconnection project started construction in Ruijin, Jiangxi. The project will build Jiangxi's first flexible DC back-to-back converter station, creating a high-speed channel for the interconnection between the Fujian and Jiangxi power grids, and helping to optimize the allocation of regional energy resources and the efficient development and utilization of new energy.

What is a "back-to-back interconnection project"?

Put simply, it is a power project that safely and efficiently connects two non-synchronously operating power grids through the conversion of "AC - DC - AC" within a converter station.

For example, the power grid systems of Jiangxi and Fujian provinces are respectively affiliated with the central and eastern regional power grids of the State Grid. There are situations where different regional power grids operate asynchronously. Therefore, power cannot be directly transmitted between the two regional power grids. The back-to-back interconnection project is equivalent to installing a high - efficiency "power converter" for the two major regional power grids, enabling two - way power transmission across regions and optimizing resource allocation.

Not long ago, five back-to-back interconnection projects, including those between Chongqing and Guizhou, Hunan and Guangdong, Hunan and Guizhou, Fujian and Jiangxi, and Anhui and Hubei, with a total investment of 24.4 billion yuan, were approved by the National Development and Reform Commission.

According to the plan, the five projects with a total investment of 24.4 billion yuan will build five flexible DC converter stations with a capacity of 3 million kilowatts, and the line length will reach 1,227 kilometers. Except for the Fujian-Jiangxi and Anhui-Hubei projects, which will be built within the operating area of the State Grid, among the three projects involving the operating areas of both the State Grid and the China Southern Power Grid, the Chongqing-Guizhou and Hunan-Guangdong projects are led by the State Grid, and the Hunan-Guizhou project is led by the China Southern Power Grid.

Previously, there have been precedents for building back-to-back interconnection projects in China. For example, the Chongqing-Hubei DC back-to-back interconnection project, which was completed and put into operation in 2019, is the world's first commercially operating flexible DC back-to-back project with the highest voltage level and the largest capacity; the Fujian-Guangdong interconnection project, which was put into operation in 2022, is the first interconnection project between the State Grid and the China Southern Power Grid.

Currently, China is accelerating the construction of a unified national power market, allowing power to cross provincial boundaries for free trading and optimized allocation on a larger scale.

In July this year, the National Development and Reform Commission and the National Energy Administration issued a reply on the plan for the regularized power trading mechanism across power grid operating areas, pointing out that realizing regularized trading across power grid operating areas is of great significance in breaking market segmentation and regional blockades and optimizing the allocation of power resources across the country.

Industry insiders analyze that after the above-mentioned power flexible mutual support projects are put into operation, they will significantly improve the power complementary support and emergency assistance capabilities between regions. In particular, they will provide a more solid physical foundation for regularized power trading across power grid operating areas and better meet the green energy consumption needs for high - quality economic and social development.

This article is from the WeChat official account "Urban Evolution Theory". Author: Liu Yanmei. Republished by 36Kr with permission.