This paper presents an energetic and economic analysis of grid-connected renewable sources with storage. The goal is to increase the self-production of a hybrid photovoltaic (PV) and wind system, avoiding a large usage of the grid to supply the loads of commercial users. Simulations are performed for one year, starting from hourly consumption data and solar irradiance and wind speed measurements updated each minute. Then, the appropriate capacity of storage is investigated with cost-effective solutions to maximize the self-consumption and to minimize the grid injections. Finally, different capacities of these renewable energy systems and storage are defined to find a cost-optimal solution.