CO2 emissions retrieval from coal-fired power plants based on OCO-2/3 satellite observations and a Gaussian plume model

The CO2 emissions from coal-fired power plants are a major source of carbon emissions in China. However, the existing emission inventory does not accurately reflect current emissions because of a lag in the statistical data and the accuracy limit for emissions factor. This study aims to provide a method for estimating CO2 emissions from coal-fired power plants based on an improved Gaussian plume model and the Orbiting Carbon Observatory 2/3 satellite. We quantified CO2 emissions from six coal-fired power plants (>3000 MW) in China using 14 plumes from the OCO-2 (2014.09.06–2021.10.01) and OCO-3 (2019.08.06–2021.10.01) datasets. Four of the plumes are in good agreement with those from co-located the Tropospheric Monitoring Instrument measurements of co-emitted NO2. The estimated CO2 emissions ranged from 31.81 to 99.71 kt/d with correlation coefficient of 0.47–0.95. The uncertainty of individual plumes varied from 8% to 42% (1σ), with wind speed being the greatest source of uncertainty, and the average XCO2 enhancement of all power plants in this study is less than 1 ppm when the wind speed increases to about 10 m/s. After validation, our results show high agreement with the existing emission inventory. However, this study found that the Carbon Monitoring for Action may have underestimated the CO2 emissions from Tuoketuo due to the timing of the update, and carbon brief may have underestimated the emissions from Wujiaqu by ignoring the high emission factor of lignite. This study helps monitor and estimate important point source carbon emissions, which is not only a prerequisite for the power industry to carry out carbon reduction efforts, but also helps develop specific regional carbon reduction policies, which are important for reducing anthropogenic carbon emissions.