Plasma gasification technology has been demonstrated in recent studies as one of the most effective and environmentally friendly methods for solid waste treatment and energy utilization. This study focuses on the thermodynamic analysis of plasma gasification technology, which includes prediction of the produced synthesis gas, energy and exergy calculations. To that purpose, an equilibrium plasma gasification model, called GasifEq, is developed here by using recent thermodynamic data, which also considers the possibility for soot formation, as a solid carbon by-product. The GasifEq model also has the capability of energy and exergy calculations that are required for the optimization of such processes. This is demonstrated by the presentation of the effect of the most important process parameters on the energetic performance of the process. (c) 2005 Elsevier Ltd. All rights reserved.