Carbon emission reduction requires attention to the contribution of natural gas use: Combustion and leakage

Abstract. Natural gas will continue to replace coal in the process of global energy structure reform, but its leakage potential can delay the realization of global carbon neutrality. To quantify its impact, we established a carbon dioxide (CO2) and methane (CH4) flux detection platform on the 220 m platform of the Institute of Atmospheric Physics, Chinese Academy of Sciences, located in northwestern Beijing. The observation results indicated that the daily mean CO2 and CH4 fluxes were 12.21 ± 1.75 µmol m−2 s−1 and 95.54 ± 18.92 nmol m−2 s−1, respectively. The fluxes were significantly correlated with natural gas consumption, indicating that natural gas has become a common source of CH4 and CO2, the combustion of which releases CO2, while its leakage processes emit CH4. Vehicle-based identification demonstrated that CH4 can escape at the production, storage and use stages of natural gas. Based on natural gas consumption data, the upper limit of the calculated natural gas leakage rate in Beijing reached 1.12 % ± 0.22 %, indicating that the contribution of CH4 to climate change could reach 23 % of that of CO2 on a 20-year scale. Natural gas leakage was estimated to delay the time for China to achieve carbon neutrality by at least almost four years.