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Many countries are still facing a common hurdle: last-mile rural electrification. Great skill is required to face this challenge, which generally involves the most isolated, inaccessible and complex regions. Many Latin American countries have already undertaken universal access to energy schemes and have built an experience base that, if shared, can add a wealth of knowledge to facilitate the implementation of future initiatives. In this regard, this work evaluates the sustainability of the main electrification initiatives developed in Brazil and Venezuela, by performing an ex-post comparative multicriteria evaluation on 18 quantitative and qualitative social, institutional, economic, technical and managerial indicators. Eight discussion threads are drawn from the programs’ design and implementation strategies and outcomes. The main insights are: the suitability of renewable-based distributed energy resources for covering last-mile rural electrification; the effectiveness of a private context for the development of the technological market and the creation of policy instruments; and the effectiveness of a public context to implement a greater diversity of technological solutions focused on improving social well-being. The lessons learned aim to guide rural electrification promoters and decision makers in developing more sustainable and successful last-mile electrification initiatives. Peer Reviewed Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant

Low-tech digesters are sustainable technologies to produce a clean fuel (biogas), which can be used for cooking and heating. Moreover, the degradation of organic waste in the digester also produces a liquid effluent (digestate), which can be reused in agriculture as a biofertilizer. The direct application of digestate to the soil may not be either feasible due to regulations or safe due to poor quality. The study aims to apply, for the first time, a multicriteria analysis to select the most suitable solution for the post-treatment and reuse of digestate from low-tech digesters implemented in small-scale farms. The post-treatments considered are: a degassing tank, a sand filter, a vermifilter, digestate recirculation, a facultative pond, and combinations of them. Ten criteria and twenty-one sub-criteria including technical, environmental and socio-economic aspects are defined to be weighted by experts. The analysis employs triangular fuzzy numbers to consider uncertainty and increase the robustness of the results, and it is validated using three case studies in Colombia. The alternatives are designed using data collected in-situ on the design and operation of the digesters and the quality of the digestates. Results confirm the robustness of the rankings and show that vermifiltration is the best alternative for the post-treatment of digestates from low-tech digesters implemented in small-scale farms. It is due to the fact that it produces a high-quality biofertilizer, it is easy to manage and it is implemented using local materials. Other prominent alternatives are sand filtration, recirculation and a degassing tank coupled with vermifiltration. Peer Reviewed Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant::7.1 - Per a 2030, garantir l’accés universal a serveis d’energia assequibles, confiables i moderns Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant::7.a - Per a 2030, augmentar la cooperació internacional per tal de facilitar l’accés a la investigació i a les tecnolo­gies energètiques no contaminants, incloses les fonts d’energia renovables, l’eficiència energètica i les tecnologies de combustibles fòssils avançades i menys contaminants, i promoure la inversió en infraestructures energètiques i tecnologies d’energia no contaminant Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant::7.b - Per a 2030, ampliar la infraestructura i millorar la tecnologia per tal d’oferir serveis d’energia moderns i sos­tenibles per a tots els països en desenvolupament, en particular els països menys avançats, els petits estats insulars en desenvolupament i els països en desenvolupament sense litoral, d’acord amb els programes de suport respectius