World's Tallest Dam Shuangjiangkou Starts Second Unit, Boosts Clean Power and Cuts Emissions

The Shuangjiangkou hydropower station in Sichuan, China, has brought its second generating unit online. This is the world's tallest dam at 312 meters. When fully operational, its total capacity will be 3 million kilowatts, producing an estimated 7.7 billion kilowatt-hours annually. The project also boosts downstream generation by 6.6 billion kWh per year and cuts regional CO2 emissions by about 7.18 million metric tons annually, equivalent to removing 1.5 million vehicles from the road. The dam uses a gravel-core rockfill design and features records like the highest in-situ stress underground powerhouse and largest-capacity hydraulic hoists. It also strengthens flood control on the upper Yangtze River and improves grid frequency regulation. The first unit connected to the grid on June 26, 2026, and the second followed within two weeks, showing rapid commissioning progress. The project supports China's carbon peaking and neutrality goals and supplies clean power to the Chengdu-Chongqing economic circle.