Overlooked CO₂ emissions induced by air pollution control devices in coal-fired power plants

China's efforts to mitigate air pollution from its large-scale coal-fired power plants (CFPPs) have involved the widespread use of air pollution control devices (APCDs). However, the operation of these devices relies on substantial electricity generated by CFPPs, resulting in indirect CO₂ emissions. The extent of CO₂ emissions caused by APCDs in China remains uncertain. Here, using a plant-level dataset, we quantified the CO₂ emissions associated with electricity consumption by APCDs in China's CFPPs. Our findings reveal a significant rise in CO₂ emissions attributed to APCDs, increasing from 1.48 Mt in 2000 to 51.7 Mt in 2020. Moreover, the contribution of APCDs to total CO₂ emissions from coal-fired power generation escalated from 0.12% to 1.19%. Among the APCDs, desulfurization devices accounted for approximately 80% of the CO₂ emissions, followed by dust removal and denitration devices. Scenario analysis indicates that the lifespan of CFPPs will profoundly impact future emissions, with Nei Mongol, Shanxi, and Shandong provinces projected to exhibit the highest emissions. Our study emphasizes the urgent need for a comprehensive assessment of environmental policies and provides valuable insights for the integrated management of air pollutants and carbon emissions in CFPPs.