The Fengning Pumped Storage Power Station, located just north of Beijing, is officially up and running as of 2025. After over 11 years of construction and an investment of $2.6 billion, the station is now the largest of its kind globally, surpassing the previous record-holder in Bath County, Virginia, according to the International Hydropower Association (IHA).

Pumped-storage hydropower stations are often referred to as “water batteries” because they offer a reliable method for storing renewable energy, such as wind and solar power, which can be intermittent. By storing this excess energy, the grid experiences less stress, reducing the likelihood of blackouts. The Fengning station, for instance, supports a nearby wind and solar farm, contributing to the efficient use of clean energy.

With a total capacity of 3.6 gigawatts, Fengning has set a new benchmark in renewable energy storage. Pablo Valverde, deputy CEO of the IHA, praised the achievement, saying, “It’s inspiring to see how the first of the renewable energies continues to break new records, support new technologies, and come up with innovative solutions.”

Pumped-storage plants consist of two large reservoirs—one positioned higher than the other. The Fengning station’s upper reservoir holds nearly 59 million cubic yards of water, while the lower reservoir stores 93.6 million cubic yards. During periods when power plants produce excess energy, water is pumped from the lower reservoir to the upper one. This stored water can remain there until needed.

When demand for electricity spikes—like during a heatwave when air conditioners are running full blast—the stored water is released from the upper reservoir. As it descends, it spins turbines that generate electricity. This process allows for efficient, on-demand power generation without the need for new water supplies, as the same water is recycled in the system.

Unlike traditional hydroelectric plants, which rely on large rivers and dams, pumped-storage stations like Fengning are designed to be more eco-friendly by reusing the water in a closed-loop system.

Pumped-storage hydropower already plays a significant role in energy storage, accounting for approximately 93% of all energy storage capacity in the United States. The capacity of these stations is enough to power every video game played in the U.S. for an entire week. And with more projects in development worldwide—such as in Nevada, Kentucky, and Scotland—pumped-storage is poised to grow even further.

As the world continues its transition to renewable energy, innovations like the Fengning Pumped Storage Power Station are crucial in ensuring that this energy is stored and distributed efficiently, helping to stabilize power grids and reduce carbon footprints.

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By Impact Lab