Considering the case of small-medium size plants based on PV (photovoltaic), an analysis was developed in order to model, simulate and optimize an electricity storage system to be coupled to a small photovoltaic plant applied to an industry load, to calculate its profitability in a given regulatory context. The case study is the current Italian electricity market The analysis was done on a small industrial plant in the area of Torino (North-West Italy), with its own photovoltaic plant connected to the public electrical grid. After an analysis of the present situation, the aim of the analysis is to understand the behaviour, from an economic point of view, of the self-consumption of renewable energy in case of a sudden deregulation of the market (switch off of feed in tariffs or RES (renewable energy system) kWh). The study includes a sensitivity analysis of the main technical and economic parameters in order to identify which of them have the greatest influence on economic performance, and therefore which parameters have to be considered with special care by the producers (technical and economic parameters) and the regulatory authorities (regulations) to decide and optimize the adoption of storage systems as a way to sustain the massive introduction of RES in the energy arena. (C) 2014 Elsevier Ltd. All rights reserved.