This paper presents a high-fidelity numerical wave tank simulation for Variable Geometry Wave Energy Converters (VG-WECs). Typically, wave energy converters require reactive power to optimize the energy conversion, which significantly jeopardizes the economic index of the system. The proposed VGWECs allows comprehensive shape-changing not only in response to ocean climate but also to reduce the reactive power requirements on the power take-off (PTO) unit. This design aims at eliminating reactive power with minimal impact on optimality in terms of energy production. To investigate the dynamic behavior of the VGWEC, this model is simulated in a Computational Fluid Dynamics (CFD) based Numerical Wave Tank (CNWT) using ANSYS 2-way Fluid Structure Interaction (FSI) tool. The interaction between irregular waves and the VGWEC is simulated. The numerical results show that the proposed VGWEC has large deformation and motion in response to the incoming wave. This highly nonlinear interaction between waves and VGWEC can be leveraged to eliminate reactive power.