Every technological innovation aimed at improving energy efficiency needs a sustainable development approach contributing to the decoupling process between environmental pollution and economic growth. The main aim of this paper is to demonstrate how the use of the hydrogen enrichment in a CHP plant represents a valid alternative to the same commercial energy systems, regarding to CO2 emissions avoidance. The paper presents an energy-environmental analysis related to the use of renewable hydrogen (produced by a PV array) for eco fuels production. Analysis of different hybrid systems configurations, based on a demo CHP (internal combustion engine) fueled with hydrogen enriched methane blends, installed at the Sapienza University Sports Centre, were carried out. A theoretical energy analysis of these hybrid systems, with an integrated CHP plant, was developed in order to evaluate the energy penalty related to this carbon avoidance technique. Finally, an environmental comparison between conventional CHP system, hybrid system and hybrid system with separated electrical generation was performed. The results show that using blends with 20% of H-2 content and tuning engine parameters, it is possible to minimize the hybrid system energy efficiency loss and to obtain the best carbon avoidance performances (about 32% respect to conventional CHP). (C) 2013 Elsevier B.V. All rights reserved.