China installs 840-ton rotor of world's largest hydro turbine at 3,000 meters altitude

Assembly of the rotor for the world's most powerful hydro turbine has been completed at the under-construction Zala hydropower station in China. The component, measuring 9.285 meters in diameter, 3.487 meters in height and weighing 840 tons, is comparable to a small house in size and to 560 passenger cars in weight.

The plant sits in a mountain gorge at an altitude of nearly 3,000 meters. Due to cold, thin air and limited space on site, the equipment cannot be delivered in one piece, so it is transported in parts and welded together at the location. Installation of the rotor demands millimeter-level precision: even the slightest displacement risks severe vibration during operation.

Zala is set to become a key facility in China's program to transmit electricity from Tibet. The station will host two 500 MW impulse turbine units — the first of their class in the country. Unlike conventional turbines, impulse units are designed for extremely high head differences: the design head reaches 671 meters, with water striking the runner directly.

Once fully operational, the station will generate about 4 billion kWh per year. That is expected to save roughly 1.3 million tons of standard coal and prevent 3.42 million tons of CO₂ emissions annually.