This study examines a 2kW photovoltaic (PV) support structure, highlighting the vulnerability of conventional metal frames to corrosion and strength degradation in harsh environmental conditions. To overcome these challenges, we propose using pultruded fiber-reinforced polymer (PFRP) members as an alternative structural material. An optimal design framework is established to identify efficient PFRP cross-sections. The study aims to determine lightweight cross-sectional dimensions for box sections (columns and girders) and C-sections (purlins) while maintaining structural safety. We evaluate structural performance using the allowable stress design (ASD) method, incorporating safety factors recommended by the American Association of State Highway and Transportation Officials (AASHTO). Finite element analysis (FEA) assesses critical design constraints, including buckling, material failure, and serviceability deflection limits. From the feasible designs, we select the lightest cross-sectional configuration that meets all safety requirements. The results demonstrate that PFRP members can significantly reduce weight while ensuring structural safety, thus validating their potential as an alternative to conventional metal photovoltaic support structures.