In this paper an optimal sizing and operation strategy for a smart Microgrid equipped with renewables/non-renewables generators and storage is presented. The general optimization objective is to define the best architecture of the Microgrid and the optimal size of the components, in order to maximize the self-consumption of the energy produced by RES. The possible arrangement of the Microgrid includes a photovoltaic system, a wind turbine, a diesel generator and a storage system. In order to assess the different configuration options and components sizing, a long-term period planning is considered. A technical and economic analysis is performed by means of the software HOMER (Hybrid Optimization Models for Energy Resources) which allows exploring several design and operation alternatives.