Access to sustainable and affordable energy services is a crucial factor in reducing poverty in developing countries. In particular, small-scale and community-based renewable energy projects are recognized as important forms of development assistance for reaching the energy poor. However, to date only a few empirical evaluations exist which analyze and compare the impact of these projects on local living conditions and their sustainability ex-post implementation. To better understand the impacts and the conditions that influence sustainability of these projects, the research presented in this paper evaluated 23 local development projects post implementation. By applying an standardized evaluation design to a cross-sectional sample in terms of renewable energy sources (solar, wind, biomass, hydro), user needs (electricity, food preparation, lighting, productive uses), community management models, finance mechanisms and geographical locations, the review results provide valuable insights on the underlying conditions that influence the success or failure of these small-scale local energy interventions. The empirical evidence suggests that the sustainability of small-scale energy implementations (≤100 kW) in developing countries is determined by the same factors, independent of the socio-cultural, political and ecological context. These findings allow to better predict the long-term success of small sustainable energy projects in developing countries, this can help to improve project designs and increase the certainty for future investment decisions.