Emission characteristics of methane point sources at coal mines in Shanxi Province based on Gaofen-5 satellite

Methane is one of the long-lived greenhouse gases, with a global warming potential 28 times that of carbon dioxide, accounting for about 16% of the global warming effect. Coal production activities are one of the main sources of methane emissions in China. As one of the main coal production bases in China, Shanxi Province’s coal industry emits a large amount of methane. Using the high-resolution remote sensing data to estimate the methane emission from the coal industry in Shanxi Province can lay a data foundation for establishing a refined methane emission inventory of the coal industry and provide scientific basis for formulating effective emission reduction measures. Using the Advanced Hyperspectral Imager (AHSI) carried by China’s GF–5–02 satellite, 838 methane plumes from 408 factories and mines in Shanxi Province’s coal mining areas were detected and their emission rates were calculated using data from October 2021 to March 2023. The results show that: ① the methane plume emission rate in Shanxi Province’s coal mining areas shows asymmetry, with 84% of the plumes having emission rates between 0.5−3.0 t/h, but there are also a few extreme cases, with the highest emission rate exceeding 10.0 t/h.② Shanxi Province has six dense areas of point source emissions of methane, five of which correspond to the high-value areas of XCH4. ③ Methane emission point sources are detected, with coal mines and coking enterprises being the majority of emission sources. The average emission rate of different types of emission sources differs greatly, and the emission rate fluctuates with time and source changes. Methane emissions may occur in all stages of the coal mining. ④ Highly persistent emission sources account for only 13% of all point sources, but contribute 41% of the total emission rate. Conversely, highly intermittent emission sources account for 59%, but contribute only 25% of the total emission rate. The comprehensive methane emission rate of the coal industry in Shanxi Province is 177.17±56.35 t/h, mainly contributed by the methane emissions from coal mines, coking and thermal power enterprises.