Uncovering the CO₂ emission evolution and reduction trends of industrial boilers in China

Industrial boilers are an important anthropogenic source of CO₂ emissions globally due to their considerable energy consumption. This study investigated the spatio-temporal heterogeneity and future reduction potential of CO₂ emissions using the first established long time-series CO₂ emission inventory of Chinese industrial boilers based on the updated localised emission factors and sub-fuel type activity level databases. Results showed that CO₂ emissions from Chinese industrial boilers were estimated at 786.9 Mt in 2022, with coal-fired industrial boilers (CFIBs) contributing the most at 83.15 %, followed by gas-fired industrial boilers (11.71 %) and oil-fired industrial boilers (5.14 %). The hotspots with high CO₂ emissions were primarily located in the northern regions with high heating demand and in the eastern coastal regions with a developed industrial economy. In addition, CO₂ emissions exhibited an evolution of fluctuating increase followed by a decline from 1980 to 2022, with CO₂ emissions peaking at 1637 Mt in 2012. Intense changes were observed in the structure of CO₂ emissions of industrial boilers, with the contribution of CFIBs dropped yearly despite the historical dominance of CFIBs in CO₂ emissions. CO₂ emissions were predicted to maintain a downward trend under energy adjustment and environmental control scenarios. CFIBs would be the leading sector for achieving future CO₂ emission reductions, with the potential expected to be 17-132 Mt, 141-302 Mt, and 223-588 Mt in 2030, 2050, and 2060, respectively. The results could provide the data basis for the scientific formulation of pollution reduction and carbon reduction policies for industrial boilers.