The availability of storage capacity plays an important role for the economic success of solar thermal power plants. For today's parabolic trough power plants, sensible heat storage systems with operation temperatures between 300degreesC and 390degreesC can be used. A solid media sensible heat storage system is developed and will be tested in a parabolic trough test loop at PSA, Spain. A simulation tool for the analysis of the transient performance of solid media sensible heat storage systems has been implemented. The computed results show the influence of various parameters describing the storage system. While the effects of the storage material properties are limited, the selected geometry of the storage system is important. The evaluation of a storage system demands the analysis of the complete power plant and not only of the storage unit. Then the capacity of the system is defined by the electric work produced by the power plant during a discharge process of the storage unit. The choice of the operation strategy for the storage system proves to be essential for the economic optimization.