Nigeria grapples with persistent energy insecurity, characterized by limited grid access, heavy reliance on fossil fuels, and mounting environmental issues. Traditional land-based photovoltaic (PV) systems often face challenges, including land-use conflicts and reduced efficiency due to thermal stress. This study examines the technical feasibility and operational performance of a Floating Photovoltaic (FPV) system at the Ikere-Gorge Dam as an energy alternative. Using RETScreen Expert software, the viability of the proposed FPV system was assessed. Key input parameters included site-specific solar irradiance, ambient/water temperatures, and detailed system specifications. The performance was evaluated using metrics such as annual energy yield, PV module operating temperature, potential for green hydrogen production, and greenhouse gas (GHG) emission reductions. The results reveal that a 37.5 MW FPV system occupying an area of 1.5 km2 could yield an annual energy generation of approximately 54,080 MWh. Furthermore, the water-body deployment effectively reduced PV module operating temperatures, boosting energy conversion efficiency from an estimated 21.5–23%. Compared to land-based PV, the FPV configuration also offered ancillary benefits, including superior spatial efficiency and mitigation of reservoir water evaporation. The system is projected to facilitate an annual reduction in GHG emissions equivalent to 22,045 metric tons of CO2 and could produce over 1.6 million kilograms of green hydrogen annually via an integrated Proton Exchange Membrane (PEM) electrolyzer. This research highlights the significant technical and environmental advantages of FPV technology, positioning it as a promising clean energy solution that could enhance energy security while supporting land resource conservation in Nigeria.