Technicians check equipment at an energy storage station in Yongzhou, central China's Hunan province. (Photo/Lei Zhongxiang)

On a mountain pass in Jiawa village, Qusum county, Shannan, southwest China's Xizang autonomous region, rows of energy storage units hum quietly beside a solar-storage power station.

"These facilities are designed to work with photovoltaic power generation. The electricity produced during the day is temporarily stored here and then released at night when demand peaks, thereby maximizing efficiency and preventing waste," explained Cui Guangze, general manager of a new energy company under China Huaneng Group, which manages these energy storage units.

This process of charging during off-peak hours and discharging during peak times exemplifies the function of large-scale battery storage systems, which are now being deployed across a rapidly expanding array of applications.

According to China's National Energy Administration (NEA), by the end of 2024, the total installed capacity of new energy storage projects in China reached 73.76 million kilowatts, representing an increase of over 130 percent compared to the end of 2023. China has emerged as a global leader in new energy technology and equipment, with its new energy patents accounting for more than 40 percent of the world's total.

Photo shows an energy storage station in Guanyun county, Lianyungang, east China's Jiangsu province. (Photo/Ren Yigang)

As China accelerates the shift toward renewable energy and builds a new type of power system, energy storage has become indispensable. As solar and wind are inherently intermittent, storage units act as "power banks" and "dispatching stations," saving excess electricity on sunny or windy days and releasing it when skies are overcast or demand surges, keeping homes lit and factories running smoothly.

Since the start of the 14th Five-Year Plan period (2021-2025), China's total installed capacity of new energy storage projects has expanded twentyfold. By the end of June this year, capacity had climbed further to 94.91 million kW/222 million kWh, up about 29 percent from the end of 2024.

"The importance of new-type energy storage is becoming increasingly evident. In 2024, we observed a significant improvement in utilization rates compared to 2023. In provincial-level regions such as Zhejiang, Jiangsu, Chongqing and Xinjiang, annual equivalent utilization hours exceeded 1,000, making storage a key driver of renewable energy integration and consumption," said Bian Guangqi, deputy director of the NEA's energy saving and technology equipment department.

This summer, as power demand repeatedly hit record highs, breaking records 36 times across 16 provincial grids, the NEA organized a centralized dispatch trial to leverage new-type energy storage for peak summer demand. The trial effectively validated the system's capacity to guarantee supply security.

By the end of July, within the service area of China's State Grid, the maximum dispatchable power from new-type energy storage reached 64.23 GW, with a real-time maximum discharge of 44.53 GW, up 55.7 percent from last year.

Photo shows China's largest "coal-to-power plus molten salt" storage project in Suzhou, east China's Anhui province. (Photo/Li Bo)

During the trial, the peak-shaving capacity of these storage systems was nearly equivalent to the output of three Three Gorges Dams, sustaining supply for an average of 2.4 hours during evening peaks and bolstering grid stability at critical moments.

In a significant technological advancement, the country's largest "coal-to-power plus molten salt" storage project, located in Suzhou, east China's Anhui province, recently completed a 168-hour trial run and officially began operation. This marks China's first gigawatt-hour-level molten salt thermal storage and exchange system integrated with a coal-fired unit.

"The molten salt system is like connecting a 'thermal battery' to a conventional cogeneration unit," explained a manager from the Suzhou Power Plant under the Anhui branch of China Energy Investment Corporation. During periods of low demand, steam heats the molten salt to store thermal energy. This energy is then released during high-demand periods, enhancing operational flexibility and addressing the long-standing challenge of balancing heating with power generation.

China's energy storage sector is rapidly diversifying project applications and accelerating the rollout of multiple technological pathways. Bian noted that in 2024, the NEA approved 56 pilot projects covering more than a dozen technical approaches, providing strong momentum for breakthroughs in core technologies and equipment.

"China's advances in new-type energy storage are moving from isolated breakthroughs to a more systematic framework," said Rao Hong, chief scientist at China Southern Power Grid.

Lithium battery technologies, he noted, are undergoing generational upgrades, with rapid progress in battery cells, thermal management, and grid integration. Meanwhile, compressed-air storage, flow batteries, and flywheel storage have achieved engineering breakthroughs, supporting the long-duration regulation needed for high-renewable systems.

Meanwhile, cutting-edge technologies such as semi-solid and all-solid-state batteries, as well as hydrogen storage, are advancing rapidly to meet future demands for multi-timescale flexibility, high safety, and resilience in extreme environments.