Cumulative power generation of six cascade hydropower stations on the main stream of the Yangtze River surpasses 35000TWh

Picture1: Wudongde Hydropower Station. Photo courtesy of China Three Gorges Corporation

Picture2: Baihetan Hydropower Station. Photo by Chen Xinbo(Xinhua News Agency)

Picture3: Xiluodu Hydropower Station. Photo by Zeng Sandong (VideoChina)

Picture4: Xiangjiaba Hydropower Station. Photo by Wu Xin (VideoChina)

Picture5: Three Gorges Hydropower Station. Photo by Zheng Kun (VideoChina)

Picture6: Gezhouba Hydropower Complex. Photo by Wang Geng (VideoChina)

Source: China Three Gorges Corporation

The mighty Yangtze River, gathering big rivers and traversing long gorges, contains abundant resources of water energy, shipping, and fresh water.

Wudongde, Baihetan, Xiluodu, Xiangjiaba, Three Gorges, and Gezhouba - these six large hydropower stations are arranged from upstream to downstream along the main stream of the Yangtze River, forming the world’s largest clean energy corridor: spanning over 1,800 kilometers, with a water level drop of over 900 meters, and a total of 110 hydro-generator units operating successively, bringing continuous green electricity with the mighty river waters.

Not long ago, the deployment of an industrial internet platform was completed at the six cascade hydropower stations, marking the basic completion of the “industrial brain” of the world’s largest clean energy corridor, significantly improving the operation efficiency and operational safety reliability of these stations.

The cumulative power generation of the six cascade hydropower stations has surpassed 35000TWh, equivalent to saving over 1 billion tons of standard coal and reducing carbon dioxide emissions by over 2.8 billion tons.Additionally, the coordinated operation of the cascade reservoirs has comprehensively released benefits in shipping, water resource assurance, and ecological protection.

Total installed capacity of 71.695GW

“One drop of water generates electricity six times”, the coordinated operation of six reservoirs makes the “green engine” even stronger

At Baihetan Hydropower Station, nestled between deep canyons, the double-curvature concrete arch dam with a maximum height of 289 meters harnesses the rushing water. The water plunging from over 200 meters height drives the turbine runners of the hydro-generator units, with each rotation generating about 150 kWh of electricity.

With 161-gigawatthydro-generator units operating at full capacity, Wang Bin, the deputy director of the operation department of the Baihetan Power Plant under China Yangtze Power Co., Ltd., said: “Operating personnel are on duty 24 hours a day, sensors collect data in real-time, and the system automatically alerts when any operational indicators show abnormalities”.

“The hydro-generator unit is like a gyro powered by water, converting kinetic energy into electricity”, explained Kang Yonglin, former deputy director of the Baihetan Engineering Construction Department of China Three Gorges Corporation (CTG). With a rotation speed of 111 revolutions per minute, a coin balanced on the unit remains motionless, while the oscillation of all bearings during operation is less than 0.1 mm… “Key technologies concerning the overall layout, electromagnetism design, and the manufacturing of major components have achieved significant innovative results, demonstrating China’s leading position in the fields of equipment manufacturing, design, and installation in hydropower".

In December 2022, Baihetan Hydropower Station achieved full operation of all its units. Looking back from Baihetan, this clean energy corridor has witnessed numerous breakthroughs in China’s hydropower technology.

Completed in the 1980s, Gezhouba features hydro-generator units with a maximum single-unit capacity of 170MW. As the largest hydropower project in the world at its time, the Three Gorges Hydropower Station overcame design and manufacturing challenges for its 700MW units. Subsequent construction of Xiluodu, Xiangjiaba, and Wudongde Hydropower Stations saw the single-unit capacity of hydro-generator units successively surpass 770MW, 800MW, and 850MW.

Upgrading is not simply addition; each round of technological research presents geometric complexity. Achieving million-kilowatt-unit capacity relies on a series of new technologies and materials, upgrading the entire industrial chain in hydraulic design, generator ventilation, and overall unit design. “The water head impact ofgigawatt-level units is greater, the rotation speed faster, and the pressure endurance higher”, said Li Haijun, deputy director of CTG’s Electromechanical Technology Center. “CTG led the development of 800 MPa high-strength volute steel plates with major steel enterprises, ending long-term dependence on imports”.

The total installed capacity of the six cascade hydropower stations reaches 71.695GW, equivalent to the capacity oftripleThree Gorges Hydropower Stations, continuously strengthening energy supply security, with five of them becoming backbone power supply stations for the “West-East Electricity Transfer” project.

“Water from the Yangtze River flows through the six hydropower stations, equivalent to one drop of water generating electricity six times”, Kang Yonglin calculated: 1 cubic meter of water passing through the Three Gorges Hydropower Station can produce 0.25 kWh of green electricity; the coordinated operation of six reservoirs achieves a multiplier effect, generating up to 2 kWh, improving efficiency by 8 times.

“The operation and scheduling of the giant cascade power stations involve multiple aspects of ‘water, machine, and electricity,’ with extensive scale, time-space variability, cross-regional and cross-network complexities. Cascade hydropower stations concurrently take on peak and base load tasks, posing higher requirements for long-term safe and stable operation of hydropower”, said Tang Zhengyang, deputy director of the Science and Technology Research Center of China Yangtze Power Co., Ltd. The deep integration of the industrial internet platform empowers all business scenarios, including intelligent operation and maintenance, intelligent inspection, smart dispatching, and intelligent decision-making, comprehensively enhancing the level of intelligent equipment operation and maintenance, supporting the digital construction of hydropower stations.

768-km deep-water channel

Releasing the ‘golden waterway’s golden benefits,’ supporting the Yangtze River’s leading freight volume

At the Three Gorges Dam, the double-line five-step ship lock sits on the left bank. In 2023, the ship lock has safely operated over 11,000 lock cycles, passing over 42,000 vessels - how to ensure safe and efficient operations as over 900-ton leaf gates open thousands of times and giant thousand-ton ships climb a 113-meter water level drop?

“The Three Gorges ship lock is the largest, has the most continuous levels, the highest water head, and the most complex operating conditions of all inland waterway locks in the world”, said Yang Hua, deputy director of the Hub Management Department of the Watershed Hub Operation Management Center of China Three Gorges Corporation (CTG), adding, “To ensure the safety and reliability of all structures and equipment, the Three Gorges ship lock undergoes regular planned maintenance halts”. On April 5, the planned maintenance halt of the Three Gorges north ship lock in 2024 was successfully completed, marking the longest, most demanding, and most complex maintenance halt since planned maintenance began in 2012. Sixteen units and over 800 participants, within 45 days, primarily completed the upgrade and renovation of the Three Gorges ship lock control system, maintenances of 12 leaf gates and 12 reverse-arc gates, and replacements of 9 sets of oil cylinders, further enhancing the safety and reliability of ship lock operations.

Passing through the Three Gorges, ships can “climb stairs” and “take elevators”. To the right of the ship lock is the Three Gorges ship lift. Yang Hua explained, a boat chamber with a height of 10 meters and a water depth of 3.5 meters can accommodate a 3,000-ton ship, lifting it to nearly 40 floors in just 10 minutes. From January to April this year, the freight volume passing through the Three Gorges ship lock exceeded 41.4 million tons, the ship lift safely operated 1,685 cycles, with a freight passing volume of over 1.96 million tons, an increase of 127.73% year on year.

The Xiangjiaba ship lift, China’s second giant ship lift after the Three Gorges ship lift, saw an increase in freight volume of 15.51% year on year in 2023; over its 40-plus years, the number of daily lock cycles of the Gezhouba ship lock has increased from 8 to 49. An official from the Watershed Hub Operation Management Center of CTG introduced that the Three Gorges, Xiangjiaba, and Gezhouba hubs have promoted the Yangtze River’s shipping and economic development along the river, supporting the Yangtze River’s freight volume to consistently rank first among the world’s inland waterways.

The six cascade hydropower stations form a 768-kilometer deep-water channel within the reservoir area, steadily improving navigation conditions on the Yangtze River.

Sections of dangerous shoals and rapids have turned into smooth waterways. Following the construction of the Three Gorges Project, the channel depth from Chongqing to Yichang has increased from 2.9 meters to 3.5-4.5 meters, the tonnage of ships has risen from 1,000 tons to 5,000 tons, and 109 shoals, 34 single-lane controlled sections, and 12 stretchers in need of hoisting have been eliminated, making “no night sailing onJinsha River” a thing of the past.

Ports have grown from small to large, then stronger. On the Yangtze River channel within Chongqing, multiple deep-water wharves of over 5,000 tons have formed. Ports in the Three Gorges Reservoir area, such as Yichang in Hubei, Fuling and Wanzhou in Chongqing, have thrived. The low energy consumption, large transportation capacity, and low costs of Yangtze River shipping have been fully utilized, further releasing the “golden waterway’s golden benefits”.

Total reservoir capacity of 91.9 billion cubic meters

Forming a strategic freshwater resource reservoir, providing support for water supply, replenishment, and ecological dispatching

The Yangtze River Basin is a strategic water source region for water resources allocation in China, with an average annual water resource volume of 995.9 billion cubic meters, accounting for about 36% of the nation’s total. Among which, this clean energy corridor forms a cascade of reservoirs with a total capacity of 91.9 billion cubic meters, acting as a strategic freshwater resource reservoir.

The benefits of water supply and replenishment are significant. Li Peng, deputy chief engineer of the Three Gorges Reservoir Scheduling of China Yangtze Power Co., Ltd., said: “We reasonably balance the storage and energy supply requirements to ensure the full play of comprehensive benefits in water supply, power generation, navigation, and ecology”.

Ecological dispatching continues to be conducted. Fish resources are vital indicators of river health, and reservoirs orderly increase discharge flow to create gradual water level rise conditions that facilitate the natural reproduction of fish. In 2023, the second year all reservoirs of Wudongde, Baihetan, Xiluodu, Xiangjiaba, and Three Gorges were included in ecological dispatching, relevant units successively coordinated and organized 12 ecological dispatching experiments, including layered water withdrawal and temperature regulation, promoting the reproduction of adhesive and drift-egg fish species. The world’s largest clean energy corridor is becoming an ecological protection corridor.

The scope of ecological dispatching continues to expand. An official from the Changjiang Water Resources Commission of the Ministry of Water Resources introduced, currently the targets of dispatching have expanded from promoting fish reproduction to layered water withdrawal and temperature regulation, algae bloom prevention, sediment reduction in the reservoir area, and controlling the overgrowth of submerged plants, among others, stretching from the Three Gorges Reservoir to cascade reservoirs on the Jinsha, Yalong, and Han Rivers, significantly advancing the protection and restoration of water ecology in the Yangtze River Basin.

An official from China Three Gorges Corporation stated that the comprehensive benefits of the world’s largest clean energy corridor provide strong support at a higher level, wider field, and larger range for flood control, navigation, energy security, and ecological safety in the Yangtze River Basin, continuously aiding the high-quality development of the Yangtze River Economic Belt.