Hybrid systems combining solid oxide fuel cells and gas turbines (SOFC/GT) have been extensively studied in recent years. They show very high theoretical electrical efficiencies and are considered as prime contenders for distributed generation. The addition of a CO2-capture system could make them even more attractive from an environmental perspective. In this study, a SOFC/GT configuration with and without a tail-end CO2 separation plant has been examined. In this work, the key parameters of the hybrid system are selected by an innovative tool based on a genetic algorithm (GA), which replaces the cumbersome parameter studies that generally are performed for this purpose. The focus is put on the evaluation of the GA as a tool for handling the multi-variable non-linear optimisation problem. The result of the optimisation procedure is a SOFC/GT system that exhibits an electrical efficiency above 60% with part capture of the CO2. (C) 2004 Elsevier B.V. All rights reserved.