China has connected its first 100 MW-class compressed carbon dioxide (CO₂) energy storage project to the grid, marking the commissioning of a 100 MW/1,000 MWh facility in Mulei Kazakh Autonomous County, Xinjiang. Developed by China Huadian, the project was connected to the grid on October 2, 2026, and uses a closed-loop CO₂ system to store and generate electricity through gas-liquid phase conversion.
Located in the Gobi Desert, the facility covers an area of more than 840 mu (approximately 138 acres). Its configuration includes five gas storage chambers, 141 liquid storage units and 97 thermal storage units. The system uses carbon dioxide as its working medium and does not depend on specific geological conditions for installation.
During off-peak hours, surplus electricity powers compressors that compress CO₂, generating heat that is captured and stored. The compressed gas is then converted into liquid form for storage. During periods of electricity demand, the liquid CO₂ is vaporised and expanded to drive generators, releasing electricity into the grid.
According to project details reported by CCTV News, the facility can store around 290 million kWh of electricity annually during off-peak periods and discharge approximately 180 million kWh during peak periods. It can provide continuous power generation for more than six hours, with a response time measured in minutes.
Once fully operational, the project is expected to generate approximately 200 million kWh of electricity annually. It is also projected to save around 50,000 tonnes of standard coal and reduce carbon dioxide emissions by approximately 170,000 tonnes each year.
The project uses a system comprising gas storage, liquid storage, compression, thermal storage, heat exchange and expansion power generation units. Its gas-liquid two-phase storage process enables energy to be stored by converting CO₂ between gaseous and liquid states. The project team has also highlighted the system’s energy density, safety and operating cost characteristics.
The facility has been selected for the fourth batch of the National Energy Administration’s first-of-its-kind major technical equipment list in the energy sector. Its commissioning is intended to support grid peak shaving, valley filling, and frequency and voltage regulation.
With the increasing share of wind and solar power in China’s electricity mix, the project is designed to provide long-duration energy storage and support the integration of renewable electricity. Its connection to the grid adds compressed CO₂ storage to the range of technologies being deployed to improve power system flexibility and accommodate renewable energy generation.
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