Power generation from gas turbines is penalised by a substantial power output loss with increased ambient temperature. By cooling down the gas turbine intake air, the power output penalty can be mitigated. The purpose of this work is to present an evaluation of the benefits of intake air-cooling in gas turbine based power plants, by modelling the integration of air-cooling in the Chania Combined Cycle power plant in Greece. Three different cooling methods are considered and compared: evaporative cooling, refrigeration cooling and evaporative cooling of pre-compressed air. The calculations are performed on a yearly basis of operation and the time varying climatic conditions are taken into account.