Applying a correction factor to the IPCC default methodology for estimating national methane emissions from solid waste disposal sites

The Intergovernmental Panel on Climate Change (IPCC) 1996 Revised Guideline s for National Greenhouse Gas Inventories proposes two methodologies for es timating methane emissions from solid waste disposal sites (SWDS): (1) the mass-balance method; and (2) the first-order kinetics method. This first me thod is the default methodology and is the easiest method to apply for esti mating country-specific methane emissions and requires the least amount of data. Alternatively, the second method is more complex and requires more in formation than the first method. As many countries do not have detailed inf ormation on solid waste disposal practices, it is anticipated that most cou ntries use and will continue to use the mass-balance approach for estimatin g time-series of methane emissions. The mass-balance approach uses an assum ption regarding annual waste disposal that can overestimate methane emissio ns. In this paper a correction factor is presented for adjusting the mass-b alance approach to account for non-steady state conditions in annual waste disposal. Use of such a correction factor results in estimates that approac h those generated by more complex methods. In summary, the analysis perform ed indicates that the modified approach typically results in more than a 20 % reduction in the methane emissions inventory and methane emissions that a re within the range of estimates based on the more complex first-order kine tics approach.