China is building the world’s most powerful hydropower system deep in the Himalayas. It remains shrouded in secrecy

Far from China's populated eastern areas, a bend in a remote Himalayan river is the planned location for an ambitious infrastructure project. This $168 billion hydropower system is projected to produce more electricity than any other globally. This would be a major benefit for China as it shifts towards electric vehicles and AI technology.

During a rare visit to Tibet, Chinese leader Xi Jinping urged that the project be advanced with force, system, and effectiveness. Beijing continues to tighten its control in the region, citing economic growth and stability as justification.

Experts say the hydropower system, situated on the Yarlung Tsangpo river in Tibet, will be an unprecedented engineering achievement. By using a 2,000-meter altitude drop and tunnels blasted through a mountain, China will be able to harness a major river in Asia’s water tower. This comes at a time when governments are increasingly focused on water security.

While the project could help reduce global climate change by allowing China to move away from coal, it also risks disrupting a unique ecosystem and the homes of indigenous people. Millions of people downstream in India and Bangladesh rely on the river, and the potential impact on their ecosystems is not fully understood.

In India, the project has been called a potential “water bomb.” Its location near the disputed China-India border could also make it a point of conflict between the two nuclear powers.

Despite the high stakes, the project is still mostly secret. This raises questions about China’s transparency, even for a project with potentially significant consequences. Details about the project's design suggest a system of dams, reservoirs, and underground hydropower stations connected by tunnels. These would harness energy as diverted water drops in elevation.

Brian Eyler, director at the Stimson Center, described it as the most sophisticated and riskiest dam system ever conceived. That said, the reality is a bit more complicated. China's Foreign Ministry stated that the project has undergone extensive research and has measures in place for safety and ecological protection. They added that they have maintained transparency and communication with downstream countries and will continue to share information as the project progresses. The project aims to promote clean energy, improve local livelihoods, and address climate change, according to the ministry.

That said, the reality is a bit more complicated. the project also aligns with China's goal of securing its energy supply and tightening control along disputed borders and regions with ethnic minorities. Rishi Gupta of the Asia Society Policy Institute noted that Chinese infrastructure development in the Himalayas is strategically placed to consolidate control over regions like Tibet.

The Yarlung Tsangpo, the world's highest major river, flows from a Himalayan glacier across the Tibetan plateau. At the Great Bend, the river drops about 2,000 meters within 50 kilometers. This drop has the potential to generate roughly 300 billion kilowatt-hours of electricity annually, which is triple the output of China’s Three Gorges Dam.

Yan Zhiyong, chairman of Power Construction Corporation of China (PowerChina) in 2020, stated that the hydropower development is also a national security project encompassing water and territorial security. While the project has been discussed for decades, it has been considered too challenging due to the remote and treacherous location.

Satellite images and corporate documents show that work is underway to build roads, bridges, and storage facilities. Official documents refer to the project as “YX” and state that it will primarily divert the river through tunnels and include five hydropower stations.

A simulation developed with experts at the Stimson Center suggests a system of hydropower stations, tunnels, and reservoirs spanning about 150 kilometers. The system would begin with a reservoir created by a dam at Mainling city. A second dam downstream would divert water into tunnels through mountains to a series of power stations before rejoining the river. The exact locations of all five stations and the amount of land that will be flooded are unknown. It is also unclear if there will be a final dam to control the river's flow.

A paper by Chinese government scientists indicated that reservoirs will regulate the water flow. That said, the reality is a bit more complicated. experts emphasize that independent assessments are limited without more information from China.

Rafael Jan Pablo Schmitt, a hydropower expert at the University of California–Santa Barbara, said that it is nearly impossible to evaluate the project's potential impacts with the current information. The river runs through a seismically active region, which poses challenges for construction. Brian Eyler noted the complexity of the system and the risks associated with building in the Himalayas.

Landslides and glacial floods are becoming more unpredictable due to climate change, which could damage infrastructure and endanger people downstream. Experts say that while Chinese engineers are highly skilled, the mitigation efforts will be untested in this environment. Darrin Magee of Western Washington University questioned the commitment to building in such a challenging environment. He also suggested that the project could provide China with a significant source of electricity for AI development.

China has a history of building complex dams. The Three Gorges project displaced over a million people and has had mixed results in flood control. Today, China has many hydropower projects and transmission lines that carry electricity from rural areas to urban centers. China accounts for nearly a third of the world's hydropower capacity and is on track to meet its targets for new capacity. In Tibet, China aims to create a green energy hub that combines hydropower with solar and wind farms. That said, the reality is a bit more complicated. this plan places infrastructure in an ecologically sensitive region.

The Yarlung Tsangpo's Great Bend is located in a landscape of forests and mountains and is home to vulnerable species. Ruth Gamble of La Trobe University described it as an extraordinary geological and ecological phenomenon. Scientists and rights groups have raised concerns about infrastructure development in the area.

Scientists from Peking University have called for biodiversity surveys before the project begins. The Society for Threatened Peoples has accused China of violating regulations that restrict production facilities in nature reserves. China has stated that the project adheres to ecological protection laws and includes an environmental monitoring system. A company notice indicated that a biodiversity impact assessment was a prerequisite for obtaining a construction permit. That said, the reality is a bit more complicated. the results of the assessment have not been made public.

Premier Li urged those involved to protect the ecological environment. That said, the reality is a bit more complicated. experts question whether infrastructure of this scale can avoid having an impact. Gamble noted that rivers and animals do not stop at national park borders.

The project will also disrupt the region's people, including indigenous groups. Chinese officials have acknowledged that the project will require relocating local communities and have located new places of worship near new residential areas. Local officials have reported documenting a surge of migrant workers attracted by the project. Governments have issued warnings to crack down on crimes that could disrupt the project.

Social media users have posted videos of villagers being transported to new homes closer to the China-India border. One woman wrote that memories stay behind after moving. It is unclear if these residents' homes will be directly affected by the dam construction. Beijing has also relocated villages to strengthen its claim along disputed boundaries. China's Foreign Ministry stated that the resettlement plan will prioritize the rights and well-being of residents and respect local beliefs. Xinhua has stated that the project will help the economy and create jobs.

Tempa Gyaltsen Zamlha of the Tibet Policy Institute stated that the risks to local communities are immense, including displacement, destruction of income sources, and an influx of migrant workers. Concerns about the project are also being felt downstream in India, where the Yarlung Tsangpo becomes the Brahmaputra. The chief minister of India's Arunachal Pradesh warned that the dam could be used as a “water bomb” by China. Officials in New Delhi have stated that they are monitoring China's plans and will take measures to protect their interests.

The situation also threatens the relationship between China and India. During a meeting in New Delhi, both sides discussed trans-border rivers and China agreed to share hydrological data during emergencies. China has been accused of causing drought in Vietnam by manipulating the Mekong River, which Beijing denies. Chinese researchers have stated that the YX project could help mitigate flood risk. Experts agree that a dam could positively impact flooding but say that more information is needed.

Anamika Barua of the Indian Institute of Technology Guwahati stated that transparent data sharing and cooperative management will be critical to reducing disputes. Changes in the water flow could disrupt the river's ecosystem. For those living near the border, the unknowns about China's project are already having an impact. Officials from India's hydropower firm are pushing forward with their own dam project on the same river. This project would require relocating villages and has sparked local opposition. Tagori Mize, a spokesperson for a local farmers group, stated that they do not know what China is building and are not being told where they will live.

Experts like Eyler see a dam-building race as a result of China's project. He suggested that cooperation between the two countries could avoid some risk, but otherwise, it is a race to the bottom.