On May 19, China’s first geothermal energy project adopting supercritical carbon dioxide for heat extraction, developed and built by China Huaneng Group, was officially commissioned in Zhengzhou, Henan Province, marking a new breakthrough in the efficient development and utilization of geothermal energy in China.

Replacing water with supercritical carbon dioxide as the heat transfer medium, the project delivers supercritical carbon dioxide to the bottom of 2,500-meter-deep geothermal wells. After absorbing underground heat, it flows back to the ground to transfer heat to heating water.

Compared with the traditional water-based geothermal heating method, supercritical carbon dioxide features higher density and lower flow resistance, delivering higher heat extraction efficiency. Its heat extraction capacity rises by around 20% while energy consumption per heating unit drops by 10%. In addition, the whole process requires no extraction of underground water, causes no stratum pollution or geological disturbance, realizing clean and safe geothermal heat harvesting.

Upon operation, the project can supply central heating for residential buildings covering over 18,000 square meters in winter. It can save approximately 288 tons of standard coal and cut carbon dioxide emissions by about 750 tons annually.