China has brought a third unit online at the Shuangjiangkou hydropower station in Sichuan, raising output to 1.5 GW while 27 heliostats help keep the record-breaking dam's clay core warm during winter construction.
China Energy Investment Corp said that the third of the plant's four 500 MW Francis turbines had entered service, Global Times reported, citing China Media Group.
The operator describes the station on the upper reaches of the Dadu River, in Aba Tibetan and Qiang Autonomous Prefecture, as home to the world's tallest dam at 315 m.
The 315 m figure is the design height. The embankment had been filled to 260 m by late June, enough to hold back the water needed for power generation, Liu Haiyang, head of construction at China Energy's Shuangjiangkou project company, told People's Daily. He said it would rise another 55 m to an elevation of 2,510 m, with the fill expected to top out in 2027.
Guinness World Records still lists the 305 m Jinping-I arch dam, also in Sichuan, as the world's highest completed dam.
Shuangjiangkou would surpass it by 10 m on completion, though Water Power Magazine has noted the title would not last long: Tajikistan's Rogun dam is designed to reach 335 m, with completion projected for the 2030s.
The station has a total installed capacity of 2 GW and a reservoir designed to hold 2.9 billion cubic meters of water, according to China News Service, which reported that the fourth unit has yet to be commissioned. Full capacity is expected by the end of 2026.
The variation in hydraulic head runs to about 80 m by the operator's figures, forcing the turbines to work efficiently across sharply different conditions.
Since June the station has delivered 500 million kilowatt-hours, Global Times reported, feeding peak summer demand in the Chengdu-Chongqing economic circle.
Once all four units run, annual output is projected at about 7.7 billion kilowatt-hours.
Chinese state media has also credited the project with adding 6.6 billion kilowatt-hours a year at downstream cascade stations.
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The Shuangjiangkou hydropower dam in Sichuan Province, China. Photo courtesy of PowerChina |
Lin Boqiang, director of the China Center for Energy Economics Research at Xiamen University, told Global Times that the project's significance goes beyond clean power because the reservoir allows water to be stored when inflows are strong and released when demand climbs or during dry spells.
That flexibility becomes more valuable as wind and solar capacity expands, he said, since reservoir hydropower can absorb the swings of intermittent sources and keep the grid stable.
The site sits in a narrow mountain valley at roughly 2,200 m, where winter temperatures fall to about minus 20 C and frozen material cannot be compacted to the required density, leaving under six months a year for some work.
Engineers installed 27 heliostats that track the sun and direct light onto the clay core, raising temperatures there by around 3 C and buying roughly three additional working hours on suitable days, according to Xinhua News Agency. More than 46 million cubic meters of material is to go into the rockfill embankment.
Chinese experts cited by Global Times said the commissioning shows a domestic capability to build the world's highest-grade rockfill dams and high-head flood discharge systems without foreign technology.
China added 6.03 GW of hydropower capacity in the first half of the year, the National Energy Administration said on July 30, split between 3.03 GW of conventional hydropower and 3 GW of pumped storage.
Total installed hydropower capacity reached 454 GW at the end of June, a figure corroborated by Carbon Brief's analysis of China's latest five-year renewables plan, with major producers generating 588.6 billion kilowatt-hours over the six months.