A model of a solar-wind hydrogen energy system was applied to the Ceara state-Brazil and the prospects for reducing emissions of fossil fuels pollutants in such federal state were studied. This long-term study simulates three scenarios of fast, slow and no introduction of hydrogen in the energy balance of the Ceara state. Not including nitrogen oxides, if fuel burning continues, results indicate that hydrogen energy eventually will reduce to zero all emissions of fossil fuels pollutants in the Ceara state by the year 2060 in both scenarios of hydrogen introduction. (c) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.