Construction started Saturday on the main structure of a 2.24-GW hydropower station on the Jinsha River, the upper section of the Yangtze River.
A cofferdam was built upstream of the construction site on Saturday in preparation for further building work.
The Yebatan Hydropower Station is located at the junction of Baiyu County in southwest China's Sichuan Province and Konjo County in Tibet Autonomous Region.
It will be the largest hydropower station on the upper reaches of the Jinsha River upon completion.
With a total installed capacity of 2.24 GW, the power station will be able to generate about 10.2 billion kWh of electricity per year.
The project is undertaken by China Huadian Corp., with a total investment of about 33.4 billion yuan (about 5 billion U.S. dollars).
Wei Yongxin, of Huadian Jinsha River Upstream Hydropower Development Co. Ltd., said the project was approved by the National Development and Reform Commission in 2016, and the power station's first generating unit is expected to start operation in 2025.
Wei added that the project had contributed to local infrastructure building and poverty alleviation.
About 240 km of roads were built by Huadian in the area around the power station. The company also upgraded an 84.5-km road linking Baiyu County and Batang County in Sichuan, cutting the travel time from over five hours to two hours for local residents.
"I earn more than 200 yuan each day working at the construction site, which is better than herding and farming," said Jampa, a Tibetan herder from Konjo County who works for the project. "More importantly, I have the chance to learn some techniques."
The power station is expected to replace 3.99 million tonnes of coal and reduce 7.37 million tonnes of carbon dioxide emissions per year after it is put into operation, said Jia Zhongqi, another Huadian official.
To protect the fragile ecosystem along the upper reaches of the Jinsha River, more than 1.5 billion yuan will be invested in environmental protection projects such as fish ladders and fish breeding stations during the construction of the power station, Jia added.
A thorough environmental impact assessment of the power station was conducted before construction started.
A total of 13 hydropower stations have been planned on the upper reaches of the Jinsha River, Wei said. The first such station, Suwalong Hydropower Station, has a designed capacity of 1.2 GW, and its first generating unit is expected to start operation in 2020.