By-production, emissions and abatement cost–climate benefit of HFC-23 in China's HCFC-22 plants

After the Kigali Amendment (KA) came into effect, HCFC-22 plants are obliged to limit HFC-23 emissions. Therefore, the study of cost-effective mitigation pathways for HFC-23 is important for the sustainable implementation of KA in China and other HCFC-22 producing countries. This study constructed an inventory of HFC-23 by-production, emissions, and abatement for HCFC-22 plants in China from 2006 to 2020, and predicted the costs and climate benefits of HFC-23 abatement in China's compliance with the KA between 2021 and 2060. Results showed that HFC-23 emissions from HCFC-22 plants in China contributed about 60% of the growth in global atmospheric mole fraction of HFC-23 observed by Advanced Global Atmospheric Gases Experiment (AGAGE) from 2007 to 2020. Furthermore, China's cumulative HFC-23 abatement was about 109 kt (1613 Mt CO2-eq) from 2006 to 2019, accounting for 53% of total by-production, which allowed the global atmospheric mole fraction and radiative forcing of HFC-23 in 2020 to avoid an uplift of 9.2 × 10−9 and 1.7 mW m−2, respectively, contributing to climate change mitigation. Under the baseline of the Kigali Amendment, less emission (LE), and resource utilization (RU) scenarios, the cumulative HFC-23 abatement from 2021 to 2060 would be 683 ± 29 kt (10,107 ± 431 Mt CO2-eq), 694 ± 29 kt (10,277 ± 427 Mt CO2-eq), and 702 ± 29 kt (10,385 ± 426 Mt CO2-eq), respectively. The cumulative net abatement costs for the KA, LE, and RU scenarios would be (5.0 ± 0.2) billion, (2.9 ± 0.2) billion, and (−2.7 ± 0.2) billion CNY (2021 prices), respectively. In the future, applying resource utilization technology to reduce HFC-23 emissions can achieve both climate and economic benefits.