China's installed capacity of pumped storage hydropower reached 50.94 million kilowatts by end-2023, the highest globally, said the China Renewable Energy Engineering Institute on Friday.

Approved PSH projects for construction reached a scale of 179 million kW by the end of last year, the institute said.

A PSH project consists of two water reservoirs at different elevations that can store or generate power as water moves from one to the other, passing through a turbine. It plays an important role in adjusting power load on the grid, as an increasing share of intermittent new energy sources are used for power generation, experts said.

They said PSH — a well-established power storage technology with economic benefits and significant potential for large-scale development — has made notable progress over the past year. This includes advancements in development scale, operational management, engineering technology and new development models.

Zhao Zenghai, deputy head of the CREEI, said that 49 new PSH stations were approved for construction nationwide last year, with a total capacity of 63.4 million kW. Newly completed operational projects totaled 5.15 million kW last year, bringing total operational capacity to 50.94 million kW.

"PSH is expected to continue growing steadily. This year, the installed capacity is anticipated to reach 57 million kW. Looking ahead, the industry will focus on demand-driven development, enhancing project layouts, steadily advancing electricity price reforms and improving industry chain coordination to drive high-quality development," he said.

Guo Jianbo, an academician at the Chinese Academy of Engineering, said: "Over the past decade, China's annual new energy growth has surpassed 90 million kW, making it the fastest-growing and largest new energy market globally. Building a clean, low-carbon, safe, efficient and flexible new type of power system requires measures such as electricity storage for flexible power load adjustment to ensure energy security. As a primary energy storage method, PSH's importance is increasingly recognized."

Xi Hao, executive vice-secretary-general of the China Society for Hydropower Engineering, said: "PSH provides multiple functions in ensuring stable power loads on the grid, including peak shaving, valley filling, energy storage and frequency adjustment. It is essential for achieving China's carbon goals and addressing the challenge of the grid's insufficient absorption of power generated from new energy sources."

Zhao said China's PSH sector has developed a comprehensive supply chain with a clear trend toward diverse investment sources, broader application scenarios and quicker adoption of new technologies.

In addition to PSH, new types of power storage technologies like compressed air are also advancing rapidly, the CREEI said. By the end of 2023, the cumulative installed capacity of operating new-type energy storage projects reached 31.39 million kW, surpassing the 14th Five-Year Plan (2021-25) target ahead of schedule.

The institute expects total energy storage capacity, including PSH and new types of power storage, to reach 600 to 750 million kW by 2035.