DUNG AVAILABILITY FOR BIOGAS PRODUCTION IN RURAL NEPAL

The lack of scientific assessments of livestock dung is hindering evaluation of the actual potential of biogas in Nepal and also formulation of effective energy strategies and policies. This study evaluates the potential of biogas production based on cattle and buffalo dung in three topographical regions of Nepal, i.e. mountains, hills, and lowland (Terai). A survey was carried out in 240 livestock-holding households. Data of daily fresh dung yield were obtained from 210 livestock individuals classified into four categories: mature buffalo (> 3 yrs), young buffalo (≤ 3 yrs), mature cattle (> 3 yrs) and young cattle (≤ 3 yrs) for three different seasons (winter, pre-monsoon and monsoon).

As expected, the average daily dung yield per livestock in the monsoon is higher than that of the other seasons for all regions because of higher fodder availability. Despite the highest livestock number per household in the mountains (5.2) as compared to the hills (2.7) and lowland (2.6), the net annual availability of dung in the mountains is only about 30% of that of the other two regions due to the relatively lower availability of fodder there. The analyses reveal that through dung-based biogas production, the annual per capita fuelwood consumption can be reduced by 114 kg DM, 344 kg DM, and 324 kg DM in the mountains, hills and lowland, respectively. The households with biogas plants use only 50% of the net available dung for biogas production, which contributes to about 25% of their total energy consumption. The findings of the study can support implementation of regionally differentiated clean energy policies and programs.