China on Tuesday commenced the construction of an ultra-high voltage (UHV) direct current transmission line linking northwest China's Xinjiang Uygur Autonomous Region and southwest China's Chongqing Municipality, said the State Grid Corporation of China (SGCC).

Stretching 2,290 km, the transmission line will pass through five provincial-level regions across the country.

The project has a rated voltage of ±800 kV, with a total investment of 28.6 billion yuan (about $3.97 billion), said the company.

Lyu Xindong, deputy general manager of State Grid Xinjiang Electric Power Co., Ltd., said that the project will be bundled with 10.2 million kilowatts of new energy, such as wind power and photovoltaics, of which new energy accounts for over 50 percent.

Once completed, the transmission line is estimated to supply electricity of over 36 billion kWh annually to central China's Henan Province, east China's Anhui Province, and Chongqing, reducing more than 16 million tonnes of carbon dioxide emissions, said Qin Shuai, deputy general manager at State Grid Chongqing Electric Power Company.

Pumped storage plant construction

A pumped storage plant, another major project of the SGCC, also started construction on Tuesday.

Pumped storage plants store energy in two water reservoirs at different elevations and generate power as water moves down from one to the other.

Located in Dufeng Country, Chongqing Municipality, the plant can supply energy to the local grid during peak usage hours. It can regulate and guarantee a safe and stable operation of the power grid in the country's southwest region, said the company.