The world's first ultra-high voltage flexible direct current (UHVDC) transmission project has commenced construction on Monday, said its operator State Grid Corporation of China, the country's largest power utility firm.

The project, the Gansu-Zhejiang ±800 kV UHVDC Transmission Project, will enable the transmission of over 36 billion kWh of electricity annually from Gansu to Zhejiang once completed, with more than half of this amount generated from renewable energy sources, it said.

Ultra-high voltage transmission lines refer to power transmission cables operating with greater than 800 kilovolts of direct current, or 1,000 kV of alternating current. Compared with traditional transmission lines, ultra-high voltage lines not only increase transmission capacity and extend transmission distances, but also reduce transmission losses.

The project, with a rated capacity of 8 million kilowatts and a total investment of about 35.3 billion yuan ($4.82 billion), passes through six provincial administrative regions, namely Gansu, the Ningxia Hui autonomous region, Shaanxi, Henan, Anhui, and Zhejiang provinces, it said.

The project stretches for a total length of 2,370 kilometers, with converter stations being constructed in Wuwei, Gansu, and Shaoxing, Zhejiang.

The project will further facilitate the large-scale development and utilization of clean energy in Gansu, optimizing the region's energy supply structure, and increasing the proportion of green electricity consumption.

After the project is put into operation, it is expected to promote the consumption of over 21.2 billion kWh of new energy electricity in the Northwest region annually, replace 6.4 million tons of coal consumption, and reduce carbon dioxide emissions by 17 million tons, it said.

The company said last week that its annual grid investment surpassed 600 billion yuan for the first time this year, 71.1 billion more than that of the previous year.

This is part of the company's efforts to accelerate the construction of a new type of power system, promote high-quality development of new energy and drive large-scale equipment upgrades and renovations, it said.

The additional investment is primarily allocated to the construction of ultra-high voltage power transmission projects, strengthening the connection between county-level grids and the main grid and upgrading grid digitalization and intelligence, said the Beijing-based State-owned enterprise.