The transition to net-zero carbon emissions necessitates innovative strategies to decarbonize sectors heavily reliant on fossil fuels. Biomethane, a biogenic renewable gas, emerges as a crucial alternative for these sectors, particularly in the context of Southern Africa’s energy landscape. This research proposes the development of a decision-making tool that integrates Life Cycle Assessment (LCA), techno-economic analysis and infrastructure and logistics requirements for biomethane production and injection into natural gas grid, focusing on Southern Africa. The study will use a multicriteria decision analysis approach to create an integrated model encompassing the entire biomethane supply chain—from feedstock sourcing to production, grid injection, and distribution. Key objectives include optimizing the location and design of biomethane production facilities, assessing the economic viability through a detailed techno-economic analysis, and evaluating the environmental impact using life cycle assessment (LCA). The research will address the challenges of integrating biomethane into existing gas infrastructure, considering grid injection standards, infrastructure modifications, and the economic and environmental benefits of a distributed biomethane system. Importantly, the model will consolidate findings from different submodels, providing key insights for developing a roadmap to reduce greenhouse gas emissions through biomethane injection into gas grid.