World's Largest Compressed Carbon Dioxide Energy Storage Project Tops Out

The main structure of the world's largest compressed carbon dioxide (CO₂) energy storage facility-jointly developed by China Huadian Corporation and Dongfang Electric Corporation-has officially topped out. The project is contracted by Dongfang Turbine Co., Ltd., a subsidiary of Dongfang Electric, marking a major milestone that lays a solid foundation for upcoming equipment installation and commissioning.

Located in Mulei Kazakh Autonomous County in the Changji Hui Autonomous Prefecture of Xinjiang, the project is a flagship new-type energy storage demonstration initiative supporting large-scale wind and solar bases in desert, Gobi, and arid regions. It is designed with an integrated capacity of 600 MW of wind power, 400 MW of solar power, and 1 GWh of energy storage. Upon completion, it will become the world's largest compressed CO₂ energy storage facility.

The project utilizes an advanced, large-scale non-combustion compressed CO₂ energy storage system. Since construction began in September 2024, all stakeholders-including project managers, supervisors, designers, equipment suppliers, labor providers, and frontline workers-have worked collaboratively and efficiently, overcoming key challenges and bottlenecks. Through rigorous planning and execution, the construction schedule has been shortened from the original 16 months to under 12 months, successfully achieving the structural topping-out milestone and paving the way for the next phase.

A spokesperson for Dongfang Turbine emphasized that the project is treated as a "top-priority initiative." The company will continue to strengthen safety and quality management, mobilize all resources, and focus efforts on critical tasks to ensure the project meets its "1130" commissioning target, aiming to deliver a high-quality, model benchmark project.

The facility adopts a non-combustion compressed CO₂ energy storage process, with an energy storage duration of up to 8 hours and a power generation window of 10 hours. It is expected to be fully operational by the end of the year, providing vital support for large-scale renewable energy integration into the grid and China's West-to-East power transmission program.

CO₂ energy storage is a novel two-phase (gas–liquid) energy storage technology. Its core principle involves compressing CO₂ gas into liquid form during off-peak electricity periods using surplus power, while simultaneously storing the heat generated during compression. During peak demand periods, the stored heat is used to re-vaporize the liquid CO₂ to drive turbines and generate electricity. This method offers several advantages, including short construction cycles, long service life, and zero carbon emissions.