Inside Baihetan: China’s mega dam powering 75 million homes

Wedged into a steep gorge on the Jinsha River, China’s Baihetan Hydropower Station had generated more than 250 billion kilowatt-hours (kWh) of electricity by June 2026, according to its operators.

They call it the world’s largest clean energy corridor, one that has met the household demand of 75 million people.

“This is the largest clean energy corridor of the world, which met the household demand of 75 million people,” Luo Yuanwang, Shift Supervisor of Shift 1, Operations Department of Baihetan Hyropower Station, told Prothom Alo on Wednesday.

While talking to him during the visit of the Baihetan Hydropower Station, he told this reporter that currently some 400 people working in the project.

Baihetan Hydropower Station is the second of the four hydropower cascade projects downstream of the Jinsha River, following Wudongde and preceding Xiluodu and Xiangjiaba.

It is located in Ningnan County, Sichuan Province, and Qiaojia County, Yunnan Province, approximately 182 km from Wudongde and 195 km upstream of Xiluodu Hydropower Station.

The project controls a catchment area of 430,300 square kilometres, accounting for 91 per cent of the Jinsha River basin upstream of the dam site.

The primary purpose of Baihetan Hydropower Station is electricity generation, while also serving flood control and navigation functions and promoting local economic and social development.

The reservoir has a total storage capacity of 20.627 billion cubic metres including 10.436 billion cubic metres of regulating storage and 7.5 billion cubic metres of flood-control storage.

The power station has an installed capacity of 16,000 MW, with an average annual power generation of 62.443 billion kWh and a guaranteed output of 5,500 MW.

The project’s major structures comprise the river-blocking dam, flood-discharge and energy-dissipation facilities, and the water-conveyance and power-generation system.

The dam is a concrete double-curvature arch dam, with a crest elevation of 834.00 metres and a maximum height of 289.00 metres. Its foundation includes a cushion slab and two auxiliary dams.

The flood-discharge and energy-dissipation facilities consist of six surface outlets in the dam body, seven deep outlets, and three flood-discharge tunnels on the left bank.

The underground powerhouse is symmetrically arranged on the left and right banks, with each powerhouse containing eight 1,000 MW Francis turbine-generator units. During construction, diversion through tunnels was maintained throughout the year.

Officials and operators at the site present Baihetan as a symbol of China’s push towards large-scale clean energy. Hydropower of this scale, they say, supplies stable, low-carbon electricity to distant load centres while also helping manage floods on one of the country’s major rivers.

Complex climatic conditions: The project site experiences extreme weather, with maximum air temperatures reaching 43°C, ground-surface temperatures approaching 70°C, and maximum wind forces reaching Beaufort Force 13.

Steep terrain at the dam site: The site lies within an asymmetrical V-shaped valley, making project planning and layout exceptionally difficult.

Unprecedented foundation geology: For the first time, a dam foundation was constructed on columnar-jointed basalt characterized by hard, brittle and highly fractured rock, making excavation relatively easy.

World-leading underground powerhouse scale: The underground powerhouse cavern complex ranks first in the world in terms of span. Surrounding rock stability posed particularly significant challenges.

High geological disaster risks: The project hub area faces substantial risks from geological hazards, including landslides and debris flows. The project is also subject to stringent seismic design and fortification requirements.

In 1991, Preliminary work on Baihetan Hydropower Station commenced in full.

In October 2010, the National Development and Reform Commission (NDRC) approved preliminary work on Baihetan Hydropower Station.

In December 2010, the Sichuan Provincial People's Government issued the project’s construction approval document, followed by the Yunnan Provincial People's Government in January 2011.

In June 2011, China Three Gorges Corporation began preparatory work for the project. River closure was achieved in November 2015.

August 2017, Full-scale construction of the main works commenced.

In May 2021, Concrete placement for the main dam was completed to the crest, and reservoir impoundment began.

In June 2021, the first batch of generating units was commissioned.

In December 2022, all generating units were commissioned.

In June 2023, the project was completed in June 2023.