Accounting socio-economic benefits of household biogas towards net zero energy transition in developing countries: A case study of Nepal

Household biogas contributes significantly to the cooking energy transition, enhances rural livelihoods, and promotes sustainable development. However, the lack of comprehensive studies on monetizing and accounting for the overall direct and indirect cost benefits of biogas plants often hinders benefit communication to people and the preparation of appropriate policy measures for net zero energy transition in many developing countries. To address these issues, this study conducted a nationwide household survey comprising 1392 primary samples in Nepal, using a benefit-accounting framework based on different biogas sizes in three ecological belts (mountains, hills, and Terai). The results revealed that an average household biogas plant replaces 4.5 tons of biomass annually. Direct annual economic savings by a one cubic meter biogas plant in the Terai region were found to be NRs 9000 (USD 69.23). In contrast, in the hilly and mountainous regions, the benefits increased by NRs 2250 and NRs 4500 respectively. Annual displacement of fuel wood by the total household biogas plants installed in Nepal accounted for 1.8 million tons and saved 2.8 million tons equivalent CO₂ emission. Besides the direct benefits, many indirect and social benefits linked to crop productivity, timesaving for economic activities, improved health, and the environment were investigated. Accounting for integral benefits, biogas plants had significant (35 to 43 %) additional benefit contributions over direct savings, which are often neglected in accounting frameworks. Government subsidies have improved the feasibility of biogas plants. Outcomes beyond these accounting values only, this study provides several policy implications for the wider-scale promotion of household biogas in developing countries for meeting net zero energy transition goals.