The beginning of this thesis deals with the classification of solar thermal power plants in renewable energy sources and presents solar radiation. The main part of the thesis includes operation procedure and presentations of solar power plants technology, which are used in practice. Followed by a technical description of the solar thermal power plant Andasol-1 with input parameters, which are used for further simulation. It captures the different modes of operation of this type of solar thermal power plants and describes heat transfer fluids which are used in the process. An important chapter is the simulation software package SAM in which the operating principles of simulation, the history and the main parts of the software package is introduced. Course description simulation follows the actual programming interface with corresponding parameters. The end of the simulation is followed by a review of the results and presentation of the differences between two different locations of the same solar thermal power.