Cu(In,Ga)Se2-based thin film solar cell devices exhibit metastable electrical behavior. This behavior is often ascribed to intrinsic defects that can change configuration accompanied by large lattice relaxations. We extended the thin film solar cell simulation software scaps to enable the simulation of the metastable behavior of this kind of defects. The statistics that are needed to describe metastable defects are discussed. The procedure that has been implemented is introduced, and special attention is paid to the convergence of the method for high defect densities. The model is demonstrated by simulating the effect of voltage induced metastabilities on the capacitance-voltage characteristics. Some of the features present in the measured apparent doping density profiles can be directly related to presence of metastable defects.