Coal to gas: the influence of methane leakage

Carbon dioxide (CO2) emissions from fossil fuel combustion may be reduced by using natural gas rather than coal to produce energy. Gas produces approximately half the amount of CO2 per unit of primary energy compared with coal. Here we consider a scenario where a fraction of coal usage is replaced by natural gas (i.e., methane, CH4) over a given time period, and where a percentage of the gas production is assumed to leak into the atmosphere. The additional CH4 from leakage adds to the radiative forcing of the climate system, offsetting the reduction in CO2 forcing that accompanies the transition from coal to gas. We also consider the effects of: methane leakage from coal mining; changes in radiative forcing due to changes in the emissions of sulfur dioxide and carbonaceous aerosols; and differences in the efficiency of electricity production between coal- and gas-fired power generation. On balance, these factors more than offset the reduction in warming due to reduced CO2 emissions. When gas replaces coal there is additional warming out to 2,050 with an assumed leakage rate of 0%, and out to 2,140 if the leakage rate is as high as 10%. The overall effects on global-mean temperature over the 21st century, however, are small.

[1]  J. Edmonds,et al.  Scenarios of Greenhouse Gas Emissions and Atmospheric Concentrations , 2007 .

[2]  Alexei G. Sankovski,et al.  Special report on emissions scenarios , 2000 .

[3]  Steven J. Smith,et al.  Global Warming Potentials: 1. Climatic Implications of Emissions Reductions , 2000 .

[4]  C. Brooks.  Climatic Change , 1913, Nature.

[5]  H. L. Miller,et al.  Climate Change 2007: The Physical Science Basis , 2007 .

[6]  Tom M. L. Wigley,et al.  Global Warming Potentials: 2. Accuracy , 2000 .

[7]  M. K. Mann,et al.  Life Cycle Assessment of Coal-fired Power Production , 1999 .

[8]  M. Pastor,et al.  Cooling the Planet, Clearing the Air: Climate Policy, Carbon Pricing, and Co-Benefits , 2012 .

[9]  A. Ingraffea,et al.  Methane and the greenhouse-gas footprint of natural gas from shale formations , 2011 .

[10]  J. Edmonds,et al.  Uncertainties in climate stabilization , 2009 .

[11]  Atul K. Jain,et al.  Substitution of Natural Gas for Coal: Climatic Effects of Utility Sector Emissions , 2002 .

[12]  T. Wigley,et al.  Could reducing fossil-fuel emissions cause global warming? , 1991, Nature.

[13]  T. Wigley,et al.  Emulating coupled atmosphere-ocean and carbon cycle models with a simpler model, MAGICC6 - Part 1: Model description and calibration , 2011 .

[14]  Roberto Schaeffer,et al.  Global warming potentials: The case of emissions from dams , 1995 .

[15]  Lukas H. Meyer,et al.  Summary for Policymakers , 2022, The Ocean and Cryosphere in a Changing Climate.

[16]  Tasneem Abbasi,et al.  Anaerobic digestion for global warming control and energy generation—An overview , 2012 .