Microgrids are sustainable solutions for electrification of rural zones that can make use of their local renewable resources. In this paper, we propose a new method for microgrid planning which includes the effect of the uncertainties of the renewable resources explicitly. Fuzzy interval models are used because they can capture nonlinearities and systematically represent the uncertainties associated with renewable resources at a certain confidence level. Relying on interval fuzzy models and by considering a set of possible scenarios for the renewable resources, the solution to the microgrid planning problem is given through the optimal sizing and topology of the microgrid. This information, particularly the optimal sizes of generators and the economic analysis, is useful for the design phase of a microgrid project. The proposed methodology is applied to the microgrid planning of the rural Mapuche community, José Painecura, in Chile.@en