This master's thesis deals with the concepts of Collective Self-Consumption and Energy Communities, which represent a way for final customers to share energy that is locally generated by renewable and high efficiency sources. Despite the long history of `energy sharing' projects in Europe, the introduction of collective self-consumers and Energy Communities in the European and National regulations is quite a revolutionary event that may, to a certain extent, disrupt the traditional way of producing and consuming energy. The idea behind this work is to support the users, which are the main focus of this new and evolving context, with a free and open-source tool to provide quick and easy-to-grasp evaluations of the performances of a configuration where energy is shared among an aggregate of households through collective self-consumption.