Building work on what will be the world's second largest hydropower station started Thursday.

The Baihetan project is located downstream of the Jinsha River, the upper section of the Yangtze, in Ningnan county of southwest China's Sichuan Province and Qiaojia county of neighboring Yunnan Province, according to the China Three Gorges Corporation.

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, which is equal to two-thirds of Beijing's electricity consumption in 2015.

According to the construction plan, the first group of units of the project are expected to start operation in 2021 and all units 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.