Pumped storage hydroelectric stations come as boon to satisfy growing demand

In late June, as a tunnel gate gradually closed, the upper reservoir of a pumped storage hydropower station in Zhejiang province began storing water for the first time. It is now ready to serve as a "super power bank" for nearby regions.

The same day, the construction officially began on a 1 million-kilowatt pumped storage hydropower project in Chongqing, the first of its kind amid the rocky limestone topography.

Three other pumped storage hydropower projects in Guangdong, Shanxi and Jiangsu provinces also received approvals for construction in June.

All these developments signal the final approvals for 100 million kilowatts of pumped storage hydropower capacity during the 14th Five-Year Plan (2021-25) period, bringing China a step closer toward its decarbonization goals.

The country's power storage industry has experienced explosive growth since 2021, as a series of large-scale, high-technology pumped storage hydropower stations have been made ready or have already started operating.

Approved as well as commissioned capacities hit record highs last year, said the National Energy Administration.

Projects such as the Yangjiang Pumped Storage Hydropower Station with a 700-meter ultrahigh water head and a single unit capacity of 400,000 kW, and the Changlongshan Pumped Storage Hydropower Station with the highest water head in China (756 meters) have begun operations.

Experts say this is a significant leap in the industry's technological level.

Unlike conventional hydropower plants, pumped storage hydropower stations serve as both power generators and consumers. Such facilities have two water reservoirs at different elevations. They pump water from the lower reservoir to the upper level when there is excess power on the grid, and release water to let it flow back downhill to generate power when there is greater demand for electricity.

This has earned pumped storage hydropower stations the nickname "super power banks".

As massive electricity is difficult to store in other ways, the stations help ensure safe and stable operation of the power system, especially after a large batch of intermittent, unstable new energies are used for power generation, experts said.

Xiong Minfeng, deputy head of the new energy and renewable energy bureau at the NEA, said China approved 48 pumped storage hydropower projects with an installed capacity of 68.9 million kW in 2022, surpassing the total approved capacity during the 13th Five-Year Plan (2016-20) period.

The total newly commissioned capacity reached 8.8 million kW last year — a record.

By the end of 2022, China's planned pumped storage hydropower sites had a total resource capacity of about 823 million kW.Among them, 45.79 million kW had already been built, and 121 million kW were under construction, according to a report jointly released by the China Renewable Energy Engineering Institute and the pumped storage hydropower branch of the China Society for Hydropower Engineering.