On February 28, the lower reservoir project of the Zhejiang Tiantai Pumped Storage Power Station, the pumped storage power station with the largest single-unit capacity in China, designed and constructed by PowerChina, successfully passed the impoundment acceptance, marking another major phased achievement in the project's construction and laying a solid foundation for achieving the goal of putting the first unit into operation for power generation by the end of 2025.

The Tiantai Pumped Storage Power Station is a key implementation project under the national Medium- and Long-Term Development Plan for Pumped Storage (2021-2035) and a key project in Zhejiang Province. The station is located in Tiantai County, Taizhou City, and mainly consists of an upper reservoir, a lower reservoir, a water conveyance system, an underground powerhouse, and a switchyard. The design and construction of the station's water conveyance system and the design and manufacture of its units are highly challenging and have set multiple records. Its pumped storage units with a single-unit capacity of 425,000 kilowatts are the largest among domestic pumped storage units, and its rated head of 724 meters and the length of its upper and lower diversion inclined shafts of 483.4 meters are both the largest among pumped storage stations under construction in China.

The station has a total installed capacity of 1.7 million kilowatts. Upon completion, it is expected to generate 1.7 billion kilowatt-hours of electricity annually, save approximately 520,000 tons of coal, and reduce carbon dioxide emissions by approximately 1.04 million tons. This is of great significance for optimizing the power source mix, improving the safe and stable operation of the power grid, and achieving the "dual carbon" goals. Upon completion, the station will undertake peak shaving, valley filling, frequency regulation, phase modulation, energy storage, and emergency accident reserve for the Zhejiang power grid, and will provide flexible dispatch capability for the East China power grid.

Overall view of the lower reservoir