Some energy projects became in causes of possible social conflicts during its implantation; in this way and in order to prevent social conflicts, it should conduct a social impact assessment (SIA) before developing an energy project. In this work, we conducted a social impact assessment on a renewable energy project in Lima, Peru, by applying of the grey systems theory. In the case study, four stakeholder groups and five evaluation criteria, for SIA, were identified. Consequently, the results showed that the energy project would have a positive social impact from the point of the view affected population. In addition, the criterion more valuated by population under analysis, was the impact on the research. Moreover, the method applied in this study showed interesting results that could help to authorities from university under study and local authorities to make the best decision about the energy project. In addition, the method could be used to assess social impact from other type of energy projects.