Assessing Methane Emissions From the Natural Gas Industry: Reviewing the Case of China in a Comparative Framework

In order to achieve a 1.5°C warming scenario, many countries have announced their ambition to achieve net-zero greenhouse gas (GHG) emissions in the next few decades. However, in addition to carbon dioxide, other key GHGs such as methane will require attention in order to achieve this goal. In the past 20 years, global methane emissions have increased by 10 percent. Although methane has a lower concentration and a shorter atmospheric lifetime compared to carbon dioxide, the 20-year global warming potential of methane is 85 times that of carbon dioxide. As a coal-dominated country, China’s coal mines represent the largest source of domestic methane emissions. Given China’s “coal-to-gas” policy promotion, natural gas is expected to play an important role in China’s coal replacement process.

In a new journal article published in Current Climate Change Reports, Xi Yang, Yiying Gao, Mingzhe Zhu and Cecilia Springer compare methane emissions from China’s fossil fuel industry with the US and Canada, with a focus on the methane emission mechanisms, calculation methods, mitigation potential and abatement technologies.

Main findings:

• Methane emissions from the natural gas production phase are the largest in the whole natural gas supply chain. 
• When it comes to measurement and estimation methods, methane emissions in the gas industry in the US and Canada typically achieve a Tier 3 level, while China tends to be at the Tier 1 and Tier 2 levels. 
  • For the three-tier system, both Tier 1 and Tier 2 quantify methane emissions based on emission factors and use a “bottom-up” method, but Tier 1 adopts Intergovernmental Panel on Climate Change (IPCC) factors and Tier 2 adopts region-specific emission factors. 
  • Tier 3 is the most accurate method for measuring methane emissions in the field, including both “top-down” methods such as “aircraft mass balance method” and “bottom-up” methods such as “point-to-point detection.”
• There is large mitigation potential for methane emissions from the natural gas industry. 
  • More effective waste reduction technologies like green well completion should be implemented in the production phase, especially in China. 
  • More attention should be drawn to the need for leakage detection technologies of pipelines in all countries compared here.

As a large methane-emitting country, China lags behind the US and Canada in methane emission reduction. The authors urge Chinese scientists, policymakers and entrepreneurs to pay attention to methane emissions. They suggest stakeholders should enhance mitigation measures and leakage detection technologies in order to achieve climate targets.