Understanding household biogas failures in Nepal: A socio-technical failure mode analysis

Household biogas offers a sustainable alternative to traditional biomass-based cooking in developing countries. However, their long-term functionality is often hindered by technical, socioeconomic, and institutional barriers. The aim of this study is to systematically identify and priorotize the major failure modes of household biogas systems in Nepal and understand how sociotechnical factors exacerbate these failures. Using failure mode and effects analysis integrated with sociotechnical systems theory, a field survey of 384 households was conducted across two ecological regions of Nepal. Twenty (20) key failure modes were identified and prioritized from system failure's perspective using risk priority number (RPN). The most critical failures were non-favorable anaerobic digestion conditions (RPN = 640), insufficient mixing (RPN = 467), and improper dilution ratios (RPN = 403). These technical issues were intensified by socioeconomic barriers such as limited affordability of maintenance, sociocultural stigmas related to waste handling, and institutional shortcomings in post-installation support. The findings suggest that performance-based subsidies, user training, localized design improvements, and stronger maintenance services are vital for sustaining household biogas adoption. Although the findings offer a diagnostic view of household biogas system performance in Nepal, their implications extend to national efforts in GHG emission mitigation, household air pollution reduction, progress toward sustainable development goals and nationally determined contributor targets. • Identified 20 key failure modes affecting household biogas sustainability in Nepal. • Integrated failure mode analysis with socio-technical systems theory. • Interpreted root cause analysis through Ishikawa (Fishbone diagram). • Emphasizes post-installation support, performance based financial incentives.