This paper shows a complete tech no-economical analysis on facilities that make use of wind turbines and photovoltaic (PV) generators for the production of hydrogen by means of electrolysis. Besides, the surplus of electrical energy produced can be sold and injected to the electrical grid. In the case studies, several scenarios have been considered with changing values for the prize of the electricity sold to the electrical grid as this is one of the parameters that most influences economical calculations. We have also made a sensitivity analysis depending on the prize of components and on the economical and meteorological changes. In each scenario - for each hour and for a period of one year - a great number of possible combinations of the system components have been simulated. These components are: photovoltaic generator, wind turbines, rectifier, inverter, electrolyser and other auxiliary elements. Each system, each combination of elements, once simulated, has been economically evaluated thus making it possible to select the best one. In the assessment of each system, there were two objectives to minimize: one of them is hydrogen selling price so the Net Present Value (NPV) equals nil and the other one is hydrogen selling price in order to recover the invested capital in a given number of years. The results achieved show that with the present cost of the components needed, and with the solar irradiation and wind conditions considered in this study, the selling price of hydrogen produced by means of electrolysis should be high in order to recover the initial investment of a PV-Wind system in a reasonable lapse of time (ten years). Nevertheless, the rising price of the spare energy sold and injected to the electrical grid by this type of equipment could help decrease hydrogen selling price. (C) 2009 Elsevier Ltd. All rights reserved.