Sustainability assessment of floating photovoltaic (FPV) system: A multidimensional comprehensive analysis across the water-energy nexus

Floating Photovoltaic (FPV) systems, also known as floatovoltaics, place solar panels on bodies of water to maximize power output, conserve land space, and reduce water evaporation. This study addresses the critical gap in comprehensive sustainability assessments of FPV systems by applying the ‘7E’ framework, which encompasses Energy, Evaporation, Economy, Environment, Ecology, Equity, and Efficiency. It utilizes the newly introduced Floating Equivalence Ratio (FER) to offer insights into the multi-dimensional benefits of FPV systems, highlighting their potential as a sustainable energy solution within the water-energy nexus. Analyzing data from a 130 kWp FPV system in Southern Brazil's Passauna reservoir, a FER value of 1.20 was found, demonstrating a 4.42 % improvement in energy generation over ground-mounted systems. The analysis reveals a significant reduction in evaporation by approximately 2715 m 3 and minimal impact on aquatic ecosystems. Economically, while the FPV system shows a slightly higher Levelized Cost of Energy (LCOE) for net energy metering (NEM) and feed-in tariff (FIT) schemes of the FPV system compared to the ground-mounted PV system, the long-term benefits include saving 81,459 m 3 of water and mitigating 257.7 tons of CO 2 emissions over a 30-year operational period. A comparative analysis of five additional reservoirs in Southern Brazil demonstrates the FPV system's sustainability benefits, positioning it favorably in a sustainability ranking among energy generation systems. These findings underscore the advantages of FPV systems, solidifying their role as a sustainable alternative to conventional photovoltaic systems and contributing valuable insights for policymakers and stakeholders in renewable energy planning.