The growing demand for energy, the reduction of fossil fuels and the need to reduce carbon dioxide emissions, have determined the increase of interest for energy efficiency. A key element of smart grids is represented by near-zero energy buildings and in the last years the focus is towards positive energy buildings and cluster of buildings. In this regard, the educational campuses equipped with small size renewable energy sources and hybrid systems can become positive energy campuses, becoming an important player capable of providing the distribution network with useful information such that to optimize the operation. This paper deals with the analysis of a cluster of educational buildings, equipped with photovoltaic installations and hybrid systems, optimized such that to minimize the operational costs. This model uses an integer linear programming method, based on different production and consumption patterns. The optimization model is applied to a cluster of buildings for university purposes, located in the south-east of Romania, near the seaside where the environmental conditions are favorable for use of renewable energy sources in conditions of electricity market operation.