Coupling of a partial oxidation reactor with a gas turbine. is proposed to increase the capacity and efficiency of thermal power plants. The exhaust of the partial oxidation gas turbine:is a preheated fuel that can be burned with little modification in the existing steam generator. The feasibility study requires the development of a reliable model for an existing 250 MW power plant. Data reconciliation is found valuable for obtaining precise mass and energy balances and for screening out unreliable measurements. The identification of model parameters from reconciled values is then straightforward.The same validation Software is later applied to rating simulation of the modified plant, by merging the partial oxidation gas turbine in the model.