$20/kWh Compressed Air Energy Storage Undercuts Lithium-Ion

The world's largest compressed air energy storage (CAES) system has been built in Huai'an, Jiangsu, with 71% efficiency by reusing compression heat. Storage cost is about $20/kWh versus $300/kWh for lithium-ion batteries, but capacity is limited to four hours.

• Cycle efficiency is 71% by reusing compression heat
• Storage cost ~$20/kWh vs ~$300/kWh for lithium-ion batteries
• Capacity is 4 hours, suitable for grid balancing but not long-duration storage
• Air is stored in underground salt caverns, limiting geography