World’s largest salt cavern compressed air storage project breaks ground

Compressed air energy storage (CAES) is expected to play a key role in China’s clean energy push and the latest project announcement attests to the fact.

According to a media statement from the state-owned Assets Supervision and Administration Commission of the State Council, construction started on a 350 MW/1.4 GWh CAES project in the province of Shangdong on September 28.

Once completed, the Tai’an demonstration project is expected to be the world’s largest salt cavern CAES project, comprising two units for a total of 600 MW. The 350 MW system, which will be delivered in the first phase, is being jointly built by China Energy Engineering Group and Tai'an-based Taian Taishan New Energy Development to the tune of CNY 2.23 billion ($311 million).

The unit is based on the 325 C low-melting point molten salt high-temperature thermal insulation compression technology. It has a designed energy storage and charging time of eight hours and a discharging time of four hours.

Once both units are delivered, the Tai’an project will be capable of generating about 1 billion kWh of power annually.

According to the Commission’s announcement, the project “will help boost advanced new-type energy storage technology, encourage consumption of renewable energy and improve recycling of the waste salt cavern resource.”

CAES is not a new technology. The first system (290 MW) was installed in Huntorf, Germany, in 1978 and is still in operation today. In 1988, the Alabama Electric Cooperative’s 110 MW CAES plant also began operations in North America. However, CAES seems to have been given a new lease on life in recent years with several large-scale projects announced in the United States, Israel and Canada.

China’s CAES ambitions are particularly big. Last month, the Chinese Academy of Sciences switched on a 100 MW compressed air energy storage system in China’s Hebei Province. The facility can store more than 132 million kWh of electricity per year.

The country's largest operational CAES system is currently a 60 MW plant built by Chinese state-owned energy group Huaneng, Tsinghua University, and China National Salt Industry Group in Changzhou, Jiangsu Province. The facility features a salt cavern, situated 1,000 meters underground and owned by China National Salt Industry Group. The system has an efficiency of more than 60% and is expected to reach a power generating capacity of 1 GW.