This paper describes and compares the results of thermodynamic and economic modelling based on integrating an existing large size steam power plant (ENEL’s Brindisi power plant-660 MWe) with hydrogen production and purification plants. ENEL is one of the main Italian power utility. The high quality of the hydrogen produced would guarantee its usability for distributed generation (e.g. by micro gas turbine, Stirling engine, fuel cell, etc.) and also for public transport (using PEM fuel cells). The proximity of an hydrogen production and purification plant to an existing steam power plant can favour connections in terms of energy requirements exchanges; the integrated system, proposed here, can represent an attractive approach to a flexible hydrogen-electricity co-production. Two different technologies for the syngas production section are considered: the pyrolysis process and direct pressurised gasification. These technologies produce syngas with different characteristics in terms of temperature, pressure and composition: this has a profound effect on the layout of the complete systems proposed in this paper. The model for the pyrolysis process is based on an existing 800 kWt coal- and biomass-fed pyrolysis ENEL’s plant placed in Bastardo (Perugia, Italy): a detailed model of the plant was created. Different coals (Ashland, South Africa, Sulcis) and biomass (Poplar, Mischantus, Wood residuals, Husk) are considered in this study to explore the real potential of mixed-fuels in terms of thermodynamic performances and costs. The results were obtained using WTEMP software, developed by the TPG of the University of Genoa, showing the performance attainable by integrating a real steam power plant with systems for hydrogen production and purification for a novel vision of clean distributed hydrogen generation.