Hydroelectric facilities totaled 8.8 million kW in installed capacity last year, leading to safe, stable power generation

Amid rolling hills and tranquil valleys in Hebei province nestles a grand structure. Capable of harnessing the power of nature and storing and releasing energy as needed, the structure — Fengning Pumped Storage Power Station — is known as the world's largest "power bank".

In the valley where the station stands, a pair of reservoirs have been constructed at different elevations. When there is excess energy in the grid, the station uses that energy to pump water from the lower reservoir to the higher one. And when there is a surge in demand for electricity, the station releases the stored water to generate electricity, just like a power bank discharges its energy to charge a phone.

Since being put into operation, the station has stored and generated 1.4 billion kilowatt-hours of electricity over the past 14 months, supplying electricity sufficient for a year's use for about 500,000 households.

In the past year, 28 facilities for storing power using hydroelectricity, like the Fengning plant, were put into operation, totaling 8.8 million kW in installed capacity, said the China Electricity Council.

As the country continues to move toward a more sustainable energy mix with renewables taking up an increasing share, China's power storage industry is experiencing rapid growth.

As a conventional form of power storage, pumped hydro — which makes up 77.6 percent of the country's total power storage projects — saw its installed capacity reach 45.79 million kW by the end of 2022, ranking tops worldwide, the council said.

The development of new types of power storage like lithium-ion batteries is also on a fast growth track. The latest data from the National Energy Administration showed that as of the end of 2022, the installed capacity of new energy storage projects put into operation nationwide had reached 8.7 million kW, with an average energy storage time of about 2.1 hours, an increase of over 110 percent from the end of 2021.

"Differing from fossil fuels, new energy power generation has higher requirements for the safe and stable operation of power systems. That's because most new energies are intermittent resources, which undergo sudden and random fluctuations. This makes it difficult to realize stable and steady power generation. In addition, it presents challenges to grid stability, such as voltage fluctuations, during power transmission," said Lin Boqiang, head of the China Institute for Studies in Energy Policy at Xiamen University in Fujian province.

In the past, fossil fuels like coal were virtually the only source of electricity, and many grid operators did not store energy because it could be an expensive undertaking. Instead, grid operators had dispatch centers that consistently managed supply to meet demand, and would burn additional coal to ramp up power generation during peak hours.

However, as concerns about climate change and resource depletion grew, the focus of power generation is gradually shifting toward renewable energy resources, such as solar and wind. The problem with these modalities is that they are intermittent and not always available when needed.

The power storage systems being developed in China can store vast amounts of energy generated from renewable sources, such as solar and wind, making it possible to use this clean energy even when the sun isn't shining or the wind isn't blowing. This will help mediate the intermittency issue that has been a major challenge in the widespread adoption of renewable energy.

With massive wind and solar projects set to be installed in the Gobi Desert and other arid areas, the development of power storage is becoming more prominent.