All units brought online at Zhejiang hydroelectricity station

Marking a monumental technological leap in ultra-high head and large-capacity energy storage, the Zhejiang Tiantai Pumped-storage Hydroelectricity Station brought all its units online last week.

As the first facility of its kind to become fully operational during the 15th Five-Year Plan (2026-30) period, the 1.7-gigawatt project, located in Taizhou, Zhejiang province, boasts the world's highest rated water head at 724 meters, according to its operator China Three Gorges Corp (CTG).

In hydroelectric engineering, water head refers to the vertical drop between the upper reservoir and the turbine units. A higher water head means greater water pressure and potential energy, allowing the station to generate more power using less water.

However, a massive 724-meter drop creates immense pressure, demanding state-of-the-art materials and cutting-edge engineering to ensure safe operation.

The mega project features four 425-megawatt reversible pump-turbine units, representing the largest single-unit capacity domestically, and utilizes a domestic record 483-meter single-stage inclined penstock, it said.

Primarily tasked with peak-shaving, valley-filling, frequency regulation, and emergency backup for the Zhejiang power grid, the station is expected to generate 1.7 billion kilowatt-hours of clean electricity annually.