Many biogas systems in Africa fail due to poor project and engineering design: insights from Southern Malawi

Abstract

Anaerobic digestion (AD) is often highlighted as a potential solution for waste management, sanitation, renewable energy production, and nutrient recovery in resource-limited settings. However, post-implementation performance of biogas systems in sub-Saharan Africa remains poorly documented., with many AD systems failing to achieve optimal outcomes. This study evaluates 61 small- and medium-scale biogas systems in Southern Malawi using a qualitative, on-site assessment combined with interviews, participatory observation, and socio-technical analysis. We develop and apply a holistic evaluation framework that integrates engineering design, system functionality, value creation, and user experience, moving beyond the commonly reported binary classifications of success and failure. None of the systems achieved what we term “blue-ribbon success,” defined as which represents an ideal scenario where a system flawlessly delivers all anticipated benefits. Instead, a small number approached “contextual success,” where systems maximised benefits, minimised negative environmental impacts while adapting to local constraints and user realities. Across the spectrum of outcomes, underperformance was most strongly associated with poor design and implementation practices, underpinned by fragmented knowledge and weak coordination among developers, installers, users, and policymakers. These gaps encompass issues around training, maintenance, and operation, ultimately affecting the success and long-term sustainability of biogas systems. Addressing these deficiencies through improved design practices, targeted education, and sustained technical support is essential to improving the viability and value of AD systems where they are needed, suitable and feasible. In fact, ascertaining where they are needed, suitable, and feasible may be the most important step during project and engineering design.