Choosing an optimal Savonius vertical-axis wind turbine (VAWT) arrangement that delivers the largest power coefficient is a significant challenge. So, in this paper, an optimization of the power performance using the Taguchi technique is presented for a three-turbine cluster of two-stage Savonius rotors. A three-dimensional, unsteady, incompressible airflow model is numerically solved using ANSYS and validated using published experimental and numerical studies. The power performance of the three VAWTs is optimized by adjusting five factors, including the relative angles between the turbines (ϕ12 and ϕ13), the rotation directions (RD), and the turbine spacings (S12 and S13). The rated power coefficient (CP) and its corresponding Tip Speed Ratio (TSR) are numerically obtained for an L16 (45) orthogonal array (OA). After the signal-to-noise ratio analysis, the optimal case is obtained. Results indicate that the configuration angles have the main effect on CP, the turbine spacing between the first and second rotors and the combination of rotation directions have the lowest effect. The optimal case is found to be (S12 = 2D, S13 = 2.4D, ϕ12 = ϕ13 = 70⁰, and RD = -, +, -), resulting in an increase of 19.69 % in CP compared to the isolated turbine at a rated TSR of 0.8.