An aerial view of the construction site of the Baihetan hydropower station, the world's second-largest hydropower project, which is located on the border of Sichuan and Yunnan provinces. [Photo/Xinhua]

KUNMING - The construction of the Baihetan hydropower station in southwest China is proceeding smoothly, with the main part of the spillway tunnel project completed on Saturday.

The hydropower station is equipped with three spillway tunnels, with a maximum discharge capacity of about 12,000 cubic meters per second and a flow speed of about 47 meters per second.

Baihetan is on the Jinsha River, the upper section of the Yangtze, straddling the provinces of Yunnan and Sichuan. Baihetan is the second-largest in China after the Three Gorges Dam project in the central province of Hubei in terms of installed capacity.

The first batch of Baihetan's generating units is scheduled to start operation in July 2021. The mega power station is expected to generate more than 62 billion kilowatt-hours of electricity per year on average after its completion and will play a vital role in reducing emissions and preventing floods.