World's Largest 'Air Battery' Goes Live
The world's largest compressed air energy storage (CAES) station is now fully operational in Jiangsu, China. The facility, which uses salt caverns to store pressurized air, represents a major milestone for grid-scale energy storage, with core equipment provided by Shanghai Electric.
The Guoxin Suyan Huai'an project, with a power rating of 600 MW and a storage capacity of 2.4 GWh, cost approximately $520 million to build. It utilizes two 300 MW non-combustion units to compress air into underground salt caverns, which are then released to generate electricity during peak demand. This facility alone can generate an estimated 792 GWh annually, enough to power around 600,000 households. This facility employs an advanced "adiabatic" CAES technology, which eliminates the need to burn natural gas during the energy release phase. The heat generated during air compression is captured and stored in molten salt and pressurized thermal water systems. This stored heat is then used to reheat the expanding air, achieving a round-trip efficiency of 71%—a significant improvement over older CAES designs. The project is a cornerstone of China's broader energy strategy, which aims to install over 180 GW of new energy storage (excluding pumped hydro) by 2027, backed by an estimated $35 billion in investment. This national push is a direct response to the rapid expansion of wind and solar power, which requires large-scale storage to ensure grid stability. The country's initial 30 GW energy storage target for 2025 was surpassed in 2023. For long-duration storage (over 8 hours), advanced adiabatic CAES is becoming more cost-effective than lithium-ion batteries. Analyst estimates place the capital cost for recent CAES projects in China between CNY 800–1,500/kWh, with a lifecycle electricity cost of CNY 0.20–0.30/kWh (approx. $28-42/MWh). This positions CAES as a competitive alternative to natural gas "peaker" plants for grid balancing. The project is led by the state-owned Jiangsu Guoxin Group, which focuses on energy investment. While Shanghai Electric provided key components like the air turbine, generators, and molten salt tanks, the primary equipment supplier for the advanced CAES system was Harbin Electric Corporation. The essential underground storage is provided by the China National Salt Industry Group, leveraging its expertise in creating and managing stable salt caverns ideal for high-pressure air storage.
