While still a couple years away from going live, China has just unveiled two turbines so massive it's hard to comprehend. With an outer diameter of 20 ft, 5 in (6.2 m), each turbine weighs 80 tons, is constructed from high-strength martensitic steel, and houses 21 water ladles.
Each one is rated at 500 MW – a world-first, but they are yet to be put to real-world use. These massive impulse turbines will be installed at the Datang Zala Hydropower Station on the Yuqu River – a smaller tributary of the Nu River in eastern Tibet.
With a vertical drop of 2,201 ft (671 m) from reservoir to turbine, it will qualify as a "high head" hydropower system, where the water source is 328 ft (100 m) or higher than the turbine, and the sheer force of gravity delivers water with enough force and speed to drive the turbines with incredible efficiency. Coupled with advancements in the ladle design, efficiency is expected to jump from 91 to 92.6%, generating an extra 190,000 kWh of electricity per day.
Each year, the Datang Zala Hydropower plant is expected to slosh out almost 4 billion kWh of energy. That's the equivalent of burning 1.3 million tons of coal, except with 3.4 million tons less CO2 in the air. The hydropower station will have a total installed capacity of 1,000 MW. China's goal is to be carbon neutral by 2060.
The project is being built by China Datang Corporation, and construction of the main section began in 2023. The Datang Corp expects it to go online by 2028. The record-breaking turbines themselves were built over four years by Harbin Electric using in-house technology.
Impulse turbines (in Datang Zala's case, it's a Pelton wheel impulse design) are a type of turbine where high-pressure water jets are aimed at the turbine's buckets to turn it. The turbine itself operates in the air, rather than being submerged in water. Impulse turbines work best with high heads. Given the sheer force the turbines have to endure 24/7, martensitic steel was chosen as it's generally stronger and more corrosion-resistant compared to other types of steel.
The most common turbine, however, is the reaction turbine – like the Francis turbine (which is what you'll find in the Three Gorges Dam). Those are fully submerged and generate torque from both pressure and moving water.
Currently, China leads the globe in new hydropower construction with 14.4 gigawatts of the 24.6 GW that came online in 2024, according to SCMP. Over half of that was from pumped storage hydropower, where reservoirs can be filled and then released into turbines on demand. China has just under 436 GW of installed capacity of hydropower. By contrast, the United States had a 103.1-GW capacity at the end of 2024.
A few months ago, I wrote a piece covering China's Yarlung Tsangpo hydroelectric project, which aims to be the largest hydroelectric dam in the world, at three times the power of the Three Gorges Dam. The trouble is, the Yarlung Tsangpo river, which later becomes the Brahmaputra, winds its way from China to India and Bangladesh. Raising a dam also raises the risk of downstream water shortages, ecological disruption, and international tension.
The Datang Zala Hydropower Station is being built on the Yuqu River, a tributary of the Nu River (known as the Salween downstream). It flows from Tibet into Myanmar, eventually draining into the Andaman Sea.
Sure, it crosses fewer borders than the Brahmaputra, but it's still an international waterway – one that has already fueled regional tensions in the past, especially with Myanmar's "complex" political landscape. The Nu/Salween river is one of the last major international rivers in Southeast Asia, and China was blocked by Myanmar from building a planned 6,000-MW hydropower project on the Irrawaddy River in 2011.
The Datang Zala project hasn't triggered the same level of global scrutiny as the proposed Yarlung project, but it still raises the same question: Who decides the fate of a river shared by millions that rely on it for drinking water, agriculture, and energy?
Source: South China Morning Post