China is building new reservoirs for a very modern reason: to store electricity.
The country’s wind and solar buildout has moved so quickly that the central challenge is no longer just adding generation. It is finding ways to keep that power available when the sun is not shining and the wind is not blowing. That is why pumped-storage hydropower, which uses electricity to move water uphill and then releases it later through turbines, has become a central part of China’s energy strategy.
The scale of the renewable buildout helps explain the urgency. In December 2020, Xi Jinping said China would reach 1,200GW of installed wind and solar capacity by 2030. China hit that level in July 2024, six years early. By the end of 2025, combined wind and solar capacity had passed 1,840GW, representing 47.3% of the country’s electrical capacity, according to one of the reports in the source set.
That expansion has continued at a remarkable pace. Reporting from The Guardian said that between January and May 2025, China added 198GW of solar and 46GW of wind. In May alone, it installed 93GW of solar capacity and 26GW of wind, figures large enough that analyst Lauri Myllyvirta said the month’s additions could generate as much electricity as Poland, Sweden or the United Arab Emirates, depending on conditions.
How Pumped-Storage Hydropower Works
Pumped-storage hydropower is a relatively simple idea with very large engineering requirements. When there is extra electricity on the grid, the system uses it to pump water from a lower reservoir to a higher one. When electricity is needed, that water is released downhill through turbines to generate power.
What makes the technology useful is not novelty but scale. One of the reports describes it as one of the most effective large-scale energy storage systems in use today, while the International Hydropower Association’s 2025 outlook places pumped storage at the center of the global hydropower pipeline. These projects are especially well suited to places with large changes in elevation, which helps explain why mountainous terrain is an advantage.
China’s plan is to use excess wind and solar electricity to pump water into elevated reservoirs, then release it when demand rises. That makes the reservoirs part of a storage system rather than just conventional water infrastructure. The same buildout is happening alongside a rapid expansion in batteries, which one of the source reports says grew by 75% in 2025 compared with 2024.
Why Storage Now Matters as Much as Generation
The logic behind the reservoir push is straightforward. Wind and solar power do not arrive on command. They depend on weather and time of day, while electricity demand follows a different pattern. The result is a growing need to move energy across time, not just generate more of it.
That is why one report describes storage as a national priority. It says China now has more pumped-storage projects under way than all other countries combined, and that the government is treating both batteries and pumped hydro as essential tools for integrating intermittent renewable power into the national energy system.
The Voltrush newsletter points in the same direction, even though the available text is limited by the paywall. Its subheading says Beijing’s new five-year plan outlines a large increase in pumped hydro storage that, together with batteries, will help integrate a huge rise in wind and solar power. That framing matches the broader picture in the other sources.
China’s Lead in Hydropower Storage
The 2025 World Hydropower Outlook adds the clearest global context. It says the worldwide hydropower development pipeline now exceeds 1,075GW, including 600GW of pumped storage and 475GW of conventional projects. It also says China added 14.4GW of new hydropower capacity in 2024, including 7.75GW of pumped-storage hydropower.
Those numbers matter because they show China is not simply adding renewable generation faster than other countries. It is also building the infrastructure needed to absorb and shift that power at large scale. The same report says China continues to dominate global hydropower development, which places the reservoir push inside a much broader effort to expand grid flexibility.
One of the source reports says China is aiming to add about 100GW of pumped-storage hydropower in five years, compared with 59GW currently. If that target is met, pumped hydro would become the base of the country’s long-duration storage system, while batteries continue to expand in parallel.
A New Phase of China’s Renewable Buildout
What these reservoirs show is that China’s energy transition has entered a new phase. For years, the headline was how many solar panels and wind turbines the country could install. Now the question is how to make that electricity usable across the day and across the grid.
That does not make generation any less important. It means generation and storage now have to grow together. China’s recent numbers in wind and solar show the supply side is still accelerating, while its pumped-storage plans show policymakers are trying to build the balancing system at the same time.
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