Hybrid solar tower power plants which use high concentration optics and high temperature air receivers are one of the most important candidates to provide a major share of the clean and renewable energy needed in the future. Computer model and simulation capability are developed in this study to evaluate the performance of a new solar tower power plant with a capacity of 20.5 MWe. The numerical simulation of gas turbine, solar field and tower receiver was performed by using a Fortran code based on ray tracing technique (Monte Carlo) and TRNSYS 16 software including TEES and STEC.03 libraries. All thermodynamic parameters of the installation such as pressure ratio, air flow, fuel consumption and concentrated solar power introduced are discussed. This study has for main objective to calculate the energetic and exergetic efficiencies of hybrid and solar electric cycles for two operating systems of the installation, first without regenerator then with regenerator and evaluate their feasibility in the south-western Algerian area.