Construction of a 350 MW/1.4 GWh Compressed Air Energy Storage (CAES) unit has begun in Shangdong, China.
The Tai’an pilot project began construction in September and is expected to be the largest CAES project in a salt cave in the world, according to a statement from China’s State Council’s Public Assets Supervision and Administration Commission. Media say the project is expected to go into operation in 2024.
Although described as a “2×300 MW” project, the initial investment and construction is for a 350 MW/1.4 GWh system with CAES high temperature molten salt thermal insulation technology and a point low melting point of 325 degrees Celsius. It takes eight hours to charge and can be discharged for four hours..
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How it works.
CAES technology works by pressurizing and channeling air into a sealed unit, in this case a salt cavern, to charge the system.
When power is needed, air, which is cooled during the charging process, is released through a heating system to expand the air which then spins a turbine generator.
The project developers are China Energy Engineering Group Co., Ltd. and Taian Taishan New Energy Development Co., Ltd., which are jointly investing 2.23 billion yuan ($311 million) in the first of two construction phases.
The Commission said the project will help promote new energy storage technologies, encourage the use of renewable energy and take advantage of the disused salt cave.
China has taken a favorable stance on this technology. Last month, a 300 MWh CAES unit in Jiangsu was connected to the grid. There are nine projects in operation or under construction totaling nearly 700MW of power and more than 5GW in the planning stage, the Asia Times reported earlier this month.
CAES technology has much lower round-trip efficiency than the two predominant forms of existing energy storage, lithium-ion batteries and pumped hydroelectric storage.
But Hydrostor, a Canadian company, says a proprietary Advanced CAES (A-CAES) solution it has developed can boost that to around 65%. A 1,600 MWh project developed by Hydrostor in Australia has just obtained funding from the Australian Renewable Energy Agency (ARENA).
