There is a growing research interest in studying microgrids in rural areas as a means to promote energy access. These microgrids could be the key to energy access on a global scale because of their many advantages compared to classic grid expansion. Despite all these qualities, feedback from microgrids in rural areas shows that most fail to reach sustainability, but the reasons for their long-term failure are still not a consensus in the literature. This work intends to contribute to understanding microgrids' sustainability and their expansion by modelling them using a systemic vision approach. For this purpose, we propose a diagnosis tool that includes energy, financial, information and social aspects. A series of study cases are analyzed through this approach, showing it as a possible diagnostic tool for microgrids in the short and long term.