

Date:
June 24, 2013
Subject:
Analysis of Default Biogenic CO2 Fraction for Municipal Solid Waste (MSW)  
EPA Contract No. EP-W-11-054; Task Order No. 04

From:
RTI International

To:
Mike Hannan
U.S. Environmental Protection Agency
Washington, DC 20460 

   I. Introduction
      Several commenters disagreed with EPA's recent proposal to reduce the default municipal solid waste (MSW) biogenic CO2 fraction to 0.55 and requested that EPA use the actual MSW fractions reported by all municipal waste combustors (MWCs) for the first three years of the GHGRP (2010-2012) to determine an appropriate default. EPA performed an analysis of all quarterly MSW biogenic CO2 fractions (determined using ASTM D7459-08 and ASTM D6866-08) submitted through the GHGRP in reporting years 2010 through 2012. 
      
   II. Summary of Analysis and Findings
      The initial data set for Subpart C was reviewed to identify all units that combusted MSW from 2010 to 2012.  The quarterly MSW biogenic CO2 fractions were then averaged for each MWC to determine each unit's annual average MSW biogenic CO2 fraction. Weighted averages (based on the reported unit level biogenic CO2 emissions) and straight averages were then determined for all MWC for each year and for the entire three year period for which data is available.  
      Substitute data was used for units that did not report biogenic fractions (as required by rule), but did report emissions from the combustion of MSW.  In this event, biogenic fractions from the same unit, but a different year were substituted (e.g., Unit A reported biogenic fractions for 2012, but not 2011.  2012 fractions were substituted for Unit A in 2011). RY 2012 is the first year that reporting of quarterly MSW biogenic CO2 fractions is required. Retroactive submittals for RY 2010 and 2011 are also required.  Verification of the MSW fraction data is currently on-going. Table 1 summarizes the results of this analysis.
      

    Table 1  -  Summary of Findings from MSW Biogenic CO2 Fraction Analysis
Parameter
                                     2010
                                     2011
                                     2012
                                   2010-2012
Total Units in Analysis
                                                                            133
                                                                            139
                                                                            144
                                                                            416
Number of Substitute Units
                                                                              2
                                                                              5
                                                                              2
                                                                              9
Percent Substituted
                                                                           1.5%
                                                                           3.6%
                                                                           1.4%
                                                                           2.2%
Minimum Biogenic Fraction
                                                                           0.52
                                                                           0.38
                                                                           0.52
                                                                           0.38
Maximum Biogenic Fraction
                                                                           0.87
                                                                           0.79
                                                                           0.72
                                                                           0.87
Weighted Average Fraction
                                                                           0.64
                                                                           0.62
                                                                           0.61
                                                                           0.62
Average Fraction 
                                                                           0.64
                                                                           0.62
                                                                           0.61
                                                                           0.62
      
