A compressed air energy storage (CAES) power station utilizing two underground salt caverns in Yingcheng City, central China's Hubei Province, was successfully connected to the grid at full capacity on Thursday, marking its official commencement of commercial operations. The project, also called Nengchu-1, utilizes the caverns of an abandoned salt mine, about 600 meters deep, as its gas storage facility. This approach creates a super "power bank" with a single unit power output of up to 300 megawatt, a storage capacity of 1,500 megawatt-hours, and an underground gas storage volume of 700,000 cubic meters, according to China Energy Engineering Corporation (CEEC), one of the project's major investors. The single unit power, energy storage capacity and conversion efficiency of this project, which broke ground in 2022, has set three world records among similar salt cavern CAES power plants, the company said. "Nengchu-1 stands out with ten features, including high power, large capacity, deep energy storage capacity, strong grid-forming capacity, and being complete green, reliable and safe. We have opened up a new track and path, and solved key technological bottlenecks as well. In the next step, we will make comprehensive plans focusing on higher efficiency, lower cost, larger-scale deployment, and broader application scenarios," said Song Hailiang, chairman of the CEEC. The principle of CAES in salt caverns is similar to that of conventional pumped storage power plants. During periods of low electricity demand, electrical energy is used to compress air and store it in underground salt caverns. The compressed air can then be released during periods of peak demand to generate electricity, experts explained. "After the CAES was put into use in Yingcheng, it can store energy for eight hours and release energy for five hours every day, with its conversion efficiency reaching almost 70 percent. It is estimated to generate an annual average of approximately 500 million kilowatt-hours of electricity, which can meet the annual power demand of 750,000 residents in Yingcheng," explained Yang Xuan, deputy chief engineer at Hubei Electric Power Dispatching and Control Center of State Grid. Utilizing the existing cavities not only mitigates geological hazards such as land subsidence and collapse in the salt mines, but also transforms the mined-out areas into valuable underground resources, said experts, thus effectively turning waste into treasure.
Song also poined out that the initiative will serve as a strong driving force for the construction of a new energy system and modern power grid in China, significantly aiding the country's transition toward a green, low-carbon future.
World's first 300-MW compressed air energy storage station fully operational in China
