| Grid-scale 
 World’s largest compressed air energy storage facility commences full operation in China
 
 A 300 MW compressed air energy storage (CAES) power station   utilizing two underground salt caverns in central China’s Hubei Province   was successfully connected to the grid at full capacity, making it the   largest operating project of the kind in the world.
 
 
   
 By
 Marija Maisch
 
 Jan 10, 2025
 
 Grid-scale
 Projects & Applications
 
 
   Image: Harbin Electric Corporation
 
 
 A landmark 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 the official   commencement of its commercial operations.
 
 The “Energy  Storage No. 1” project utilizes the caverns of an  abandoned salt mine,  reaching up to 600 meters of depth, as its gas  storage facility. This  allows for a gas storage volume of nearly 700,000  cubic meters,  translating into a single unit power output of up to 300  MW and a  storage capacity of 1,500 MWh. The system conversion efficiency  is  about 70%. It can store energy for eight hours and release energy  for  five hours every day, and generate about 500 GWh of electricity   annually.
 
 According to the project operator China Energy  Engineering Corp  (CEEC), Nengchu-1 has set three world records in terms  of the single  unit power, energy storage capacity and conversion  efficiency.
 
 The Yingcheng project started construction in  July 2022 with the  technical support of the Institute of Rock and Soil  Mechanics (IRSM) of  the Chinese Academy of Sciences (CAS). Its  operational life is expected  to reach 25 years.
 
 The  announcement related to the Yingcheng project closely follows  progress  on another landmark compressed air project in China – the  Jintan Salt  Cavern CAES project in Changzhou, Jiangsu province. In late  December,  construction commenced on phase two of the project   freaturing two 350 MW non-fuel supplementary CAES units, with a total storage volume of 1.2 million cubic meters.
 
 This scale makes the Jintan project the world’s leading CAES project   in terms of single-unit power generation capacity, total storage   capacity, and integrated efficiency of any CAES facility worldwide.   Namely, the plant’s storage capacity will allow for up to 2.8 GWh of   electricity per full charge, with an estimated annual 330   charge-discharge cycles.
 
 CAES is considered a mature  technology for deep decarbonization and  GW-level deployment with  technological components that are proven and  used in industry for  decades. Its operational principle is similar to  the one of pumped  hydro. During periods of low electricity demand,  electrical energy is  used to compress air and store it in underground  salt caverns.
 
 However, the fact that CAES relies on underground caverns, making it   geology dependent, has been a major hurdle to widespread global   adoption. With its abundant salt mine resources, China offers   significant potential for the deployment of CAES, which can in turn   mitigate geological hazards such as land subsidence and collapse in the   salt mines and transform the mined-out areas into valuable resources.
 
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