Three Gorges Dam

Construction of the Three Gorges Dam on the Yangtze River began in 1994 and the dam wall was completed in 2006, though the last of its 32 main generators did not come online until 2012. The project had been debated in China for nearly a century—Sun Yat-sen proposed it in 1919 and Mao Zedong championed it again in the 1950s. Final approval came from the National People's Congress in 1992, with one of the largest dissenting votes in the body's history. The total cost was officially around 180 billion yuan (roughly US$30 billion at construction-era exchange rates), though independent estimates run significantly higher.

At 22,500 MW of installed capacity, Three Gorges produces more electricity than any other power plant on Earth—roughly the output of 22 large nuclear reactors. The dam plays three roles simultaneously: it generates about 2% of China's total electricity, it provides flood control for the lower Yangtze (which has historically killed hundreds of thousands of people in major flood years), and it allows ocean-going ships to navigate 2,400 km upstream to Chongqing. As a single piece of infrastructure, few projects in human history match its combined impact on industry, transportation, and disaster mitigation.

The 660-km reservoir submerged 13 cities, 140 towns, and over 1,600 villages, displacing roughly 1.4 million people. Sediment that historically traveled to the Yangtze delta is now trapped behind the dam, contributing to coastal erosion in Shanghai and beyond. The reservoir has been linked to landslides on its steep banks and to changes in regional rainfall and temperature. On the positive side, the dam displaces roughly 90 million tonnes of coal burning per year, avoiding an estimated 180 million tonnes of CO2 emissions annually compared to a coal-equivalent alternative.

The project was opposed inside China by hydrologists, archaeologists, and writer Dai Qing, who was jailed in 1989 after publishing a book of critical essays. Reports of induced seismicity, methane release from rotting flooded vegetation, and the loss of habitat for the now-functionally-extinct Yangtze river dolphin have continued to draw scrutiny. In 2020, China's Ministry of Water Resources publicly denied viral claims of dam deformation seen in satellite imagery.

• The reservoir behind the dam holds 39.3 km³ of water—enough that it has slowed Earth's rotation by a measurable 0.06 microseconds per day.
• Each of the 32 main generators weighs about 6,000 tonnes, the equivalent of an Eiffel Tower per turbine.
• The ship lift on the dam can lift a 3,000-tonne vessel through a 113-metre height difference in about 40 minutes.
• The dam wall is 2,335 metres long and 185 metres tall—roughly the height of a 60-storey building.
• Three Gorges has been struck by lightning over 100,000 times since opening.