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World’s first commercial supercritical CO2 power generator now online
3/12/2025
News
China National Nuclear Corporation (CNNC) has brought online the world’s first commercial supercritical CO2 power generator, it has been reported.
The generator, which uses CO2 instead of steam to transfer heat, has been connected to the grid from a steel production plant in China’s south-western province of Guizhou to produce electricity from waste heat, the South China Morning Post has reported.
Once operational, the two 15 MW power units are expected to be 50% more efficient at capturing and using waste heat from steel production to generate electricity than existing steam power technology.
The supercritical CO2 waste heat power generator is located at the state-owned Shougang Shuicheng Steel plant in the city of Liupanshui. It is thought to be the world’s first commercial grid-connected unit of its kind.
The teams behind the project – CNNC’s Nuclear Power Institute and Jigang International Engineering and Technology – believe these efficient, compact power systems could be fitted to produce power from mobile nuclear power sources, spacecraft and concentrated solar plants.
Thermal power plants typically rely on two main thermodynamic cycles. The Rankine cycle, used in steam power plants, involves heating water contained in a closed circuit until it changes into water vapour or steam, which is used to drive a turbine and produce electricity.
The Brayton cycle, used in gas turbines and jet engines, involves compressing gas to a high pressure and then heating it, causing it to expand and drive a turbine.
Supercritical CO2 has the properties of both a gas and a liquid, as it has been taken above a critical pressure and temperature.
This can be powered by waste heat, including that generated by sintering – a process used to compact and bond powdered steel. The waste heat can reach temperatures above 700°C.
When using high-temperature heat sources, the efficiency of the Rankine cycle used in steam power plants is limited to about 40%, according to the Institute of Mechanics of the Chinese Academy of Sciences.
In comparison, the properties of supercritical CO2 allow for power generation efficiency to reach over 50%, even with high-temperature heat sources.
Supercritical CO2 is also denser than steam, meaning units can be made with smaller turbines and other components for the same amount of power generation.
The Nuclear Power Institute of China has been researching and developing supercritical power units for more than a decade. In 2019, the Institute achieved stable, full-power supercritical CO2 power generation in a laboratory. It began construction on the new units in October 2023.
