<p>This study evaluates the energy, exergy, environmental, and economic performance of soil-based and water-based photovoltaic (PV) systems in Samsun, Turkey, using identical 12&#xa0;W polycrystalline panels. The water-based system demonstrated superior performance, maintaining a module temperature 14.18% lower than its soil-based counterpart. This temperature reduction led to a 24.4% increase in energy output and an annual 13.1% improvement in exergy efficiency. At midday, the water-based system achieved 12.95% energy efficiency, compared to 10.56% for the soil-based system, marking a 16.5% improvement. Exergy efficiency was 14.28%, 14% higher than the soil-based system. Additionally, the water-based system reduced CO₂ emissions by 14,769.88&#xa0;kg annually, a 13.3% improvement. Despite higher initial costs, the water-based system was economically viable, achieving a net present value of $568.92, a return on investment of 84%, and a payback period of 8.9&#xa0;years. The findings highlight the potential of water-based PV systems in hot climates and land-constrained areas. Future research should focus on scalability, cost efficiency, and long-term reliability to enhance adoption.</p> Graphical abstract <p>Performance comparison of water- and soil-based PV systems.</p> <p></p>