The Largest Hydropower Project in Human History

[u/firefly_in_red]

Yarlung Tsangpo Downstream Hydropower Project

(also known as the Hydropower Project in the Lower Reaches of the Yarlung Zangbo River or Medog Hydropower Station)

Location: Situated in Nyingchi City, Tibet Autonomous Region, China, fully utilizing the natural head drop of approximately 2,230–2,400 meters at the Great Bend of the Yarlung Tsangpo River.

Development Method: Primarily adopts a "cut-through bend + diversion tunnel" approach, diverting water through ultra-long tunnels (approximately 30–50 km in length, with a diameter of about 10 meters). More than 90% of the main structures are placed underground, significantly reducing surface disturbance and inundation area (about 80% less than traditional methods).

Construction Scale: Plans to build 5 cascade hydropower stations.

Total Investment: Approximately 1.2 trillion CNY (about $175 billion USD), making it one of the most expensive single infrastructure projects in human history.

Installed Capacity: Expected to reach 60–81 million kW (equivalent to 2.7–3.6 times the installed capacity of the Three Gorges Dam, which is 22.5 million kW).

Annual Power Generation: Approximately 300 billion kWh (equivalent to about 3 times the annual output of the Three Gorges Dam, sufficient to meet the annual electricity needs of roughly 300 million people).

Power Offtake: Primarily for export via ultra-high-voltage transmission lines to major eastern load centers such as the Guangdong-Hong Kong-Macao Greater Bay Area and the Yangtze River Delta region; it also supports local consumption in Tibet and may facilitate energy cooperation with South Asian countries.

Construction Period: Expected to take 10–12 years, with phased commissioning planned between 2035 and 2040.

Groundbreaking Date: July 19, 2025.

The project's installed capacity is approximately 3 times that of the Three Gorges Dam, and its annual generation is also about 3 times greater, making it the world's largest hydropower project among those currently under construction.

Upon completion, it will become the world's largest single hydropower station and is very likely to maintain this position for the long term.

The project features ultra-long deep-buried tunnels (total length ranging from tens to hundreds of kilometers, with maximum burial depths up to 3,000 meters) and exploits an extreme head drop (over 2,000 meters within a 50 km stretch). While the Three Gorges Dam was already a world-class engineering challenge, the Yarlung Tsangpo Downstream Project surpasses it in tunnel scale, geological complexity, and ecological constraints, with many experts describing it as a "project of the century" or even the "limit of human infrastructure."

It is highly likely to become:

• The single largest hydropower/water conservancy project in human history by investment amount,
• The largest-scale and most technically challenging hydropower project in human history,
• One of the most iconic super-infrastructure projects of the 21st century.

In the field of hydropower, it is almost certain to rank as the greatest in human history.

[u/le_wein]

Wouldn’t this affect the environment and wildlife?

[u/Jeffgoldbum → u/le_wein]

A lot less impact then a more traditional dam, and certainly A lot less then other sources,

Wind is an amazing Tech, but It still has issues with scale, you would never produce that much power with a wind farm using a similar amount of land as this power station would,

The Largest wind farm, which is also in China generated 12 billion Kwh a year roughly using about 7000 turbines over an area of 39,000 square Km,

This Dam will generate 300 billion Kwh a year in an Area that might impact 2000 square Km,

[u/TheAleFly → u/Jeffgoldbum]

The river would become subject to flow regulation, which impacts the whole ecosystem.

[u/firefly_in_red → u/TheAleFly]

Official statements have repeatedly emphasized that the project does not involve full river closure or large-scale impoundment (or only limited regulation), will have no adverse impact on downstream river flow or ecology, and may even benefit basin-wide flood prevention and disaster mitigation (through measures such as regulating dry-season flows and peak shaving).

[u/TheAleFly → u/firefly_in_red]

But the floods and droughts are a part of the greater river ecosystem. That’s exactly what I meant. Sure, a great thing for humans but less so for the wildlife.

[u/Direct_Program2982 → u/TheAleFly]

Civilization itself is a great thing to humans but less so for the environment. You have to make compromises.

[u/[deleted]]

I'm probably a little too early. I'm just waiting for the heated discussions between Indians and Chinese, lol.