Building work on what will be the world's second largest hydropower station started Thursday.
The Baihetan project is on the Jinsha River, the upper section of the Yangtze, straddling Sichuan and Yunnan provinces.
With a total installed capacity of 16 million kilowatts, the project is expected to generate more than 60 billion kilowatt hours of electricity per year, equal to about two-thirds of Beijing's electricity consumption in 2015.
The power will be generated in 2021 and the plant fully operational by the end of 2022.
With a 300-meter-high dam, the project can manage a basin area of 430,000 square kilometers, 91 percent of the Jinsha River's basin area.
Nearly 100,000 residents in Sichuan and Yunnan will be relocated to make way for the project.
Baihetan, one of four hydropower stations in the lower reaches of the Jinsha River, is downstream of the Wudongde plant that is under construction.
Xiluodu and Xiangjiaba started operations in 2013 and 2012 respectively.
With a combined installed capacity of more than 46 million kilowatts, the four projects can generate 190 billion kilowatt hours each year, doubles that of the Three Gorges, the world's largest hydropower project.
Baihetan is significant in development of the Yangtze River Economic Belt and adjustment of China's energy structure, according to Lu Chun, chairman of the China Three Gorges Corporation.
The new project will be equivalent to nearly 20 million tonnes of standard coal, cutting carbon dioxide emissions by 52 million tonnes per year, according to Lu.