Trade-offs between Manure Management with and without Biogas Production

Table 6: Average life-cycle GHG profiles for manure management systems.

Components	Average GHG Emissions (kg CO₂-eq FU^-1)
-	I. Without biogas	II. With biogas
Manure management ^a	20.55 (19.19) ^a	16.24 (16.11) ^a
Wood-fuel	33.41 (33.32)	-
Residues-fuel	17.65 (17.16)	-
Dung-fuel	15.37 (14.94)	-
Biogas loss ^b	-	9.77 (9.74)
Biogas use	-	15.16 (14.74)
Biogas digestate	-	1.92 (2.17)
Total	86.98 (84.61)	43.09 (42.76)
Saving (I- II)	43.89 (41.85) kg CO₂-eq FU^-1
Reduction factor	50.5% (49.5%)
kg CO₂-eq _saved m^-3_{biogas-available}	4.99 (4.68)

FU: 365 kg _{fresh-manure AU}^-1yr^-1. Figures in the parentheses are for buffaloes. ^aThe N₂O emission has a considerable higher share (>85%) of the total GHG emissions. This is not unusual in the solid manure management which is a common practice in developing countries [³⁹]. ^bAccounts for the 10% biogas leakages which contains ~55% methane (0.67 kg m^-3) and ~40% CO₂ (1.98 kg m^-3).