Chinese news websites including Bohai Today reported in late September that the committee that governs the Nandagang Industrial Park of Bohai New District has signed a strategic cooperation framework agreement with a subsidiary of China Huadian Corporation. The deal will see the development of DG PV projects and a compressed-air energy storage (CAES) project. The signing of the agreement came after the two sides finished an in-depth negotiation over investment amount, project specifications, project sites, and development schedules. Huadian is one of the major state-own power generation companies in China. Bohai New District is part of Cangzhou, a prefecture-level city in Hebei Province.
Under the framework agreement, Huadian’s subsidiary will invest CNY 1.5 billion into Nandagang. Of that amount, CNY 1 billion will be used to construct a 200MW/1,600MWh CAES facility, and CNY 500 million will be used to set up PV systems on the rooftops of the buildings located within the industrial park. The planned PV generation capacity is 150MW, though the actual installations and the development timetable will depend on the available local resources as well as local conditions. As for the CAES project, it will be developed in two phases. The first phase will install 100MW/800MWh.
CAES has been in existence since the late 1800s, and Germany built the first utility-scale CAES project in 1970s. However, persistent technical and safety issues have hampered the progress in the development of the technology. The principle behind CAES is the creation and release of heat resulting from the compression and decompression of ambient air or a special gas within a confined space like a storage tank or an underground cavern. Hence, the electricity produced by renewable generation systems can be converted into stored compressed air during the off-peak period of power consumption. When the peak-load period arrives, the compressed air is expanded and releases the heat that is then used to drive generation turbines. Currently, the more advanced CAES projects have a thermal energy storage component instead of a combustion engine for reconverting the compressed air into electricity. They do not require additional fuel while providing a higher level of efficiency and a wider scope of applications.
China has been researching CAES and designated the technology as a critical part of the national energy infrastructure development within the 14th Five-Year Plan. In July last year, the Chinese Academy of Sciences announced that it completed the testing of a 100MW advanced CAES expander.