LNG absorbs a significant amount of heat and releases substantial cold energy during regasification. Recovering and utilizing this cold energy has significant economic and environmental value. It is estimated that the usable cold energy from one ton of LNG is approximately one-quarter of the energy consumed in producing one ton of LNG; effective recovery can greatly save resources.
Cold energy utilization is mainly divided into two categories: direct utilization and indirect utilization. Direct utilization includes applying cold energy directly to refrigeration, air separation, cryogenic pulverization, dry ice manufacturing, and seawater desalination. Indirect utilization mainly refers to converting cold energy into electrical energy through thermodynamic cycle processes such as the cryogenic Rankine cycle, i.e., cold energy power generation.
In China, cold energy utilization technology has entered the industrial application stage. In 2025, my country's first domestically produced LNG cold energy power generation unit was put into operation at CNOOC's Ningbo "Green Energy Port." This unit uses a cryogenic Rankine cycle process, with propane as the working medium, utilizing the temperature difference between seawater and LNG to drive a turbine for power generation, achieving a cold energy utilization rate of over 70%. Its core equipment, such as the turbine expander and intermediate medium vaporizer, is 100% domestically produced. The device is designed to generate 23 million kilowatt-hours of electricity annually, meeting approximately 25% of the receiving terminal's power needs and saving over 10 million yuan in electricity costs annually.
Cold energy recovery and utilization also has significant environmental benefits. In traditional LNG regasification processes, seawater or air is typically used as a heat source. Directly discharged low-temperature seawater causes a drop in local sea surface temperature, creating "cold pollution" and damaging the marine ecosystem. Cold energy recovery technologies, such as cold energy power generation, utilize a closed-loop system to fully recover and utilize cold energy, completely eliminating this type of environmental pollution.
In the future, cold energy utilization models are developing towards diversification and integration. For example, exploring a "cold energy + hydrogen energy" model, utilizing LNG cold energy to reduce the energy consumption of hydrogen liquefaction; or combining it with liquid air energy storage technology, using cold energy to pre-cool air and improve energy storage efficiency. With the promotion of related projects in LNG receiving terminal-intensive areas such as the Yangtze River Delta and Pearl River Delta, and the development of skid-mounted devices adapted to inland storage tanks, the scale of the cold energy economy is expected to continue to expand.