Multi criteria sustainability assessment of biogas production in Kenya

Energy poverty is a global threat to sustainable development and improved livelihoods hence the availability of clean, affordable, reliable and sustainable energy is a central issue to Kenya’s national development objectives. Biogas technology in Kenya has been earmarked as one of the main drivers towards the elimination of energy poverty in majority of rural households and to this end different biogas digester models are actively promoted. Consequently, assessing the sustainability of the biogas systems in Kenya is one of the topical issues driving the discussion on biogas development. Hence developing an assessment technique capable of reliably screening the different alternatives and highlighting the sustainability hot spots is of critical essence in decision making for all biogas stake holders in the country. This paper comparatively analyses the common biogas production systems in Kenya by linking the biogas energy with infrastructures of production. A multi criteria perspective is employed for the analysis focusing on technical, economic and environmental sustainability dimensions. The evaluation in the work follows the Life Cycle Sustainability Assessment (LCSA) methodology based on the ISO 14040 and 14044 environmental management principles. It is observed that the tubular and the fixed dome digesters with respective cumulative multi criteria sustainability scores of 70% and 57% are the most sustainable with respect to animal manure as the predominant feedstock. The multi criteria sustainability assessment approach as presented in this study can constitute a vital tool for interventions in the biogas energy sector. The biogas multi-criteria sustainability assessment approach as presented in this work might be a very vital tool for biogas policy formulation in Kenya and a wide range of developing countries.

► To produce biogas from waste in Kenya, energy inputs are limited to 1.89MJ/mbiogas3.
► The energy invested in biogas production for 20 years can be recouped in 26 months of digester operation.
► Kerosene replacement by biogas resulted in GHG reduction of up to 1.09KgCO2eq/mbiogas3.
► Biogas production yielded a fossil energy replacement saving of up to 37$Cents/mbiogas3.
► Tubular biogas digester scored better in six of the nine impact criteria considered.