Performance and economic evaluation of floating (FPV) and land-based PV (LBPV) systems on reservoirs: a multi-site case study

Pakistan faces a critical energy-water-climate nexus, characterized by chronic electricity shortages, freshwater scarcity, and climate vulnerabilities. This study presents the first comprehensive, site-specific techno-economic, environmental, and direct comparative analysis of Floating Photovoltaic (FPV) and Land-Based PV (LBPV) systems across four major hydropower reservoirs in Pakistan (Aza Khel, Darawat, Mana Storage, and Tanda). Utilizing high-resolution PVsyst simulations over a 25-year horizon with standardized 1 MWp configurations, we integrate performance modelling, financial analysis, and hydrological assessment. Results demonstrate that FPV systems consistently outperform LBPV, achieving 1.3–2.5% higher annual Performance Ratios and yielding 3.8–5.2% more energy (38–52 MWh/year per site). Economically, while FPV entails 8% higher initial capital expenditure, its superior energy yield and significant co-benefits result in competitive Levelized Cost of Electricity (LCOE) and stronger financial returns (e.g., IRR of 15.3–16.4% for FPV vs. 14.6–15.9% for LBPV). A critical environmental advantage is FPV's capacity to reduce reservoir evaporation by 4,885–8,141 m3 annually per 4,652 m² coverage, directly enhancing water security. Cumulatively, each FPV plant avoids 11,632–15,760 tCO₂ over its lifetime. This research establishes a replicable methodological framework for multi-criteria assessment of solar technologies. It provides robust, quantitative evidence that FPV is not merely an alternative but a multi-benefit solution for Pakistan, synergizing clean energy generation with sustainable water management and climate resilience. The findings offer actionable insights for national energy policy, infrastructure planning, and investments aimed at a low-carbon, water-secure future.