Integrating life cycle assessment into biogas policy and practice: a systematic review and pathways for sustainable anaerobic digestion in Uganda

Abstract

Anaerobic digestion turns organic waste into biogas energy and Life Cycle Assessment (LCA) offers a standardised way to evaluate its environmental impacts across the full system. Global AD – LCA studies (2014–2025) written in English excluding non-LCA, non-AD, non-English, irrelevant policy were systematically reviewed until 29 July 2025 to inform policy for Uganda. Searches of Scopus, Web of Science, Google Scholar, and PubMed, plus targeted grey-literature screening, identified 124 studies though screening, full text assessment and citation mining out which 49 AD-LCA studies were analysed in depth. Most evidence came from Europe (61%), Asia (24%), and none originated from Uganda or sub-Saharan Africa. Methodologically, 88% used cradle-to-grave boundaries and 84% used attributional LCA, with climate-change impacts most frequently reported; few studies addressed Uganda’s abundant feedstocks or alignment with national development goals. Risk of bias was low in 45 studies, moderate in 2, and high in 2. A five-phase roadmap was proposed to address the context gaps including capacity development, adoption of open-access LCA tools, generation of local data, integration into regulatory and planning frameworks, and circular-economy applications. Limitations include English/time restrictions, heterogeneity precluding meta-analysis, and lack of prospective registration. This review was not registered and was funded by TWAS and DFG.