Methane Leakage Measurement of Natural Gas Heating Boilers and Greenhouse Gas Emissions Accounting of “Coal-to-Gas” Transition for Residential Heating in Rural Beijing

Abstract

The “coal-to-gas” transition, a widely advancing replacement of coal with natural gas (NG) for residential heating in northern China since 2017, has been confirmed to have significant environmental and health benefits. Since China proposed carbon peaking and carbon neutrality targets, the importance of accurately measuring the emissions of greenhouse gases (GHGs), mainly carbon dioxide (CO2) and methane (CH4), has been highlighted. However, due to the deficient estimates of CH4 leakage from natural gas heating boilers (namely, “gas boilers”), there is still a lack of reliable assessment of its GHG emissions. Here, applying a high-precision CO2–CH4 analyzer, we examined 30 gas boilers in Beijing, China. Based on stoichiometry, emission factor, and global warming potential (GWP) methods, we estimated the CH4 leakage rates of gas boilers and reassessed the reduction in GHG emissions from the transition. Considering the CH4 leakage rate of gas boilers, which was 0.22% [0.13, 0.30]%, the “coal-to-gas” transition for residential heating in rural Beijing reduced GHG emissions by 44.8% in end use. Our findings fill the gaps in CH4 leakage measurement and GHG emissions accounting and provide data support for the amendment of NG appliance standards and the evaluation of energy transition policies in China.