This paper presents a new CSP performance model for the System Advisor Model (SAM) tool developed by NREL and Sandia National Lab. The Generic Solar System (GSS) provides a general and flexible tool for predicting the annual performance and financial viability of concentrating solar power (CSP) systems. With the GSS, the modeler can specify the solar field optical and thermal performance using a lookup table and polynomial correlations. Performance of the power conversion system is likewise specified in terms of ambient conditions, incident solar radiation, and total load. This paper discusses the motivation and formulation for the GSS and provides model verification by comparing predicted annual results from a more detailed parabolic trough annual performance model with an equivalent implementation in the GSS.