23. For the quantification of avoided CH4 emissions attributable to the project, the promoter must calculate the CH4 emissions in the project scenario using Equations 8 to 11:Equation 8: Calculation of CH4 emissions from the anaerobic digestion of manure
Where:
PE = CH4 emissions from the project, in metric tonnes CO2 equivalent;
CLE = CH4 emissions attributable to constant leaks of biogas during normal operation of the project facilities, calculated using Equation 9, in metric tonnes CH4;
DE = CH4 emissions attributable to the decomposition of liquid digestate in the manure pits, calculated using Equation 11, in metric tonnes CH4.
Equation 9: Calculation of CH4 emissions attributable to constant leaks of biogas
Where:
CLE = CH4 emissions attributable to constant leaks of biogas during normal operation of the project facilities, in metric tonnes CH4;
n = Number of agricultural facilities;
i = Agricultural facility;
QCH4 max, i = Maximum CH4 production from eligible manure by agricultural facility i, calculated using Equation 4 or Equation 6 for the correction of the volatile solids rate, in cubic metres CH4;
MCFdigester = Conversion factor for CH4 in the digester, default value = 0.70;
0.02 = Default leak factor at anaerobic digestion facility;
WAE = Weighted average efficiency of all CH4 reclamation and destruction devices used, calculated using Equation 10;
0.668 = Density of CH4, in kilograms per cubic metre;
0.001 = Conversion factor, kilograms to metric tonnes.
Equation 10: Calculation of the weighted average efficiency of all CH4 reclamation or destruction devices
Where:
WAE = Weighted average efficiency of all CH4 reclamation and destruction devices used;
y = Number of reclamation or destruction devices used;
d = Reclamation or destruction device;
BGd = Biogas sent to reclamation or destruction device d, in cubic metres of CH4 at standard conditions;
DEFd = Efficiency factor for CH4 reclamation or destruction device, determined in Appendix A.
Equation 11: Calculation of CH4 emissions from digestate storage
Where:
DE = CH4 emissions attributable to the decomposition of digestate while in storage, in metric tonnes CH4;
a = Number of digestate storage systems;
S = Digestate storage system;
n = Number of agricultural facilities;
i = Agricultural facility;
QCH4 max, i = Maximum CH4 production from eligible manure at agricultural facility i, calculated using Equation 4 or Equation 6 for the correction of the volatile solids rate, in cubic metres CH4;
0.668 = Density of CH4, in kilograms per cubic metre;
MCFdigester = Conversion factor for CH4 in the digester, default value = 0.70;
DS = Fraction of digestate sent to storage system S;
MCFS = CH4 conversion factor achieved in the digestate storage system, determined in Table 1 of Appendix D.