Several Combined Heat and Power (CHP) system options have been considered for evaluation with respect to the end-user requirements. These included Internal Combustion Engines (Otto and Diesel), Gas Turbines, Steam Turbines and Combined Cycles covering a wide range of electrical output. Data have been obtained from literature and the CHP systems have been evaluated using different criteria such as overall efficiency, investment cost, fuel cost, electricity cost, heat cost, CO2 production and footprint. A multi-criteria method is used with an agglomeration function based on the statistical evaluation of weight factors. The technical, economic and social aspects of each system have been evaluated in an integrated manner and the results have been compared by means of the Sustainability Index. Based on the above criteria and depending on the user requirements, the best CHP system options have been established. (c) 2006 Elsevier Ltd. All rights reserved.