The distributed generation realized by renewable energy sources will be largely developed in the future years. This penetration poses different questions as the optimal sizing, maximum revenues and returns etc. Using meteorological data for a given site, this paper evaluates the productivity of different types of generators with small or medium rated power - wind generator, photovoltaic module and hydro power unit. Once this is done, an optimization of the system size is made with maximum annual revenue objective, based on the energy potential and the electricity purchase prices. These instructions give you basic guidelines for preparing camera-ready papers for symposium proceedings.