There is wide agreement in the literature that non-technical factors play a decisive role in the successful implementation of bioenergy projects. One underlying reason is that such projects require the involvement of many stakeholders, such as feedstock producers, engineers, authorities and the concerned public. We analyze the role of bioenergy-specific non-technical factors for the success of bioenergy projects. In a broad literature review we first identify potential success factors belonging to the five dimensions project characteristics, policy framework, regional integration, public perception and stakeholders. Using these factors as conceptual framework, we next analyze six Japanese pilot projects for bioenergy utilization supported by Japans Agriculture, Forestry and Fisheries Research Council. We apply Rough Set Analysis, a data mining method that can be used for small sample sizes to identify patterns in a dataset. We find that, by and large, non-technical factors from all five dimensions - such as the stability of the local policy framework - co-occur with project success. Furthermore, we show that there are diverging interpretations as to what success in a bioenergy project means. This requires tradeoffs between various goals, which should be identified and addressed explicitly at early stages of such a project.