Securing energy supply and speeding up the shift towards a sustainable,reliable,low-carbon energy systems are among the main recent and future challenges facing our world at nowadays.Among renewable energy sources,solar energy has set up itself as one of the most feasible energy resources.The dispatchable nature of solar thermal power plants makes them idyllically suited to form the backbone of a future clean energy.However,despite these promising attributes,the cost of energy from present solar thermal power plants remains expensive.In spite of several decades of solar thermal power plants development,a step-change in this area is required to drive down costs.Integrated solar thermal power plants are a promising new alternative,allowing a significant reduction in fossil fuel consumption and increased conversion.Hybrid operation is an additional attractive feature of integrated solar power plants,facilitating control and ensuring the power plants are existing to meet demand at any time occurs.The main objective of this dissertation is to investigate the possible modifications of a gas turbine tri-generation plant via integrating it with two different Concentrating Solar Power(CSP)technologies.These CSP technologies are namely,Parabolic Trough Collector(PTC)systems,and Linear Fresnel Reflector(LFR)systems.In this regard,the annual performance of an integrated solar gas turbine tri-generation power plant with different electric generation capacities of gas turbine and solar collector’s area have been examined using THERMOFLEX(?)software under weather data of different five locations worldwide.Furthermore,a conceptual process to determine the optimum configurations of the integrated solar gas turbine tri-generation plant has been developed and presented in this study.Moreover,a comparative study has been developed with conventional CO2 capturing technology integrated with conventional tri-generation plants for avoiding the same CO2 emissions avoided by the solar integration in order to determine whether integrating solar energy with the tri-generation power plants is economically feasible or not.This study revealed that the solar integration of CSP technologies with solar gas turbine tri-generation power plant results in a minor increase in cost of levelized electricity compared to the conventional tri-generation plant,nevertheless it reduces the levelized electricity cost by 62-71.5%relative to the fully-solar-powered PTC power plants and by 75.8-81%compared with that of the stand-alone LFR solar thermal power plant.Moreover,the study revealed that the most economically-thermodynamically-environmentally feasibility configurations are ones resulting from the integration of the optimal solar field areas of PTC or LFR with the 130 MWe gas turbine electric generation capacity replacing the conventional tri-generation plants considered in this study.Furthermore,the simulation results revealed that the integration of LFR with tri-generation plant is more economically feasible in comparison with the integration of PTC for all gas turbine capacities considered.Moreover,the study revealed that the integration of LFR technology with a conventional tri-generation power plant in high insolation regions has more economic feasibility(with more than 7.5%reduction in LEC)compared to equivalent conventional tri-generation plant integrated with CO2 capturing technology while achieving the same emissions reduction result.The results also revealed that the proper location to apply optimally solar integrated is in regions with high levels of solar radiation and low ambient temperature.