China’s 600 MW/2.4 GWh storage plant becomes world’s largest CAES site

With 600 MW of installed capacity and 2,400 MWh of storage, the Huai’an Salt Cavern project is now the world’s largest compressed air energy storage (CAES) facility, surpassing the 300 MW/1,500 MWh project commissioned earlier this year that previously held the title.

March 5, 2026 Marija Maisch

Image: Shanghai Electric

From ESS News

While CAES remains a relatively small share of China’s total energy storage market compared with batteries and pumped storage, the sector is expanding rapidly as larger long‑duration projects move forward.

The newly commissioned 600 MW/2.4 GWh Huai’an Salt Cavern project dramatically increases deployed CAES capacity, claiming the title of the world’s largest such project. Earlier, in January 2026, the record was held by a 300 MW/1.5 GWh CAES plant using two underground salt caverns in central China’s Hubei province.

Huai’an’s lead may be short‑lived, however, with a 700 MW/4,200 MWh CAES project in Sanmenxia’s Shanzhou district already in development.

For now, the Huai’an Salt Cavern CAES demonstration project in Jiangsu Province stands as the largest operating facility of its kind globally. The project features two 300 MW CAES units, utilizing roughly 980,000 cubic meters of salt caverns located 1,150–1,500 meters underground. It employs non‑supplementary combustion high‑temperature adiabatic compression technology, based on molten salt and pressurized thermal water, achieving approximately 71% conversion efficiency.

To continue reading, please visit our ESS News website.

This content is protected by copyright and may not be reused. If you want to cooperate with us and would like to reuse some of our content, please contact: editors@pv-magazine.com.