Thermodynamic and Technoeconomic Assessment of a Multigeneration Renewable Energy System for Energy Independence in Gn. Fuvahmulah and L. Gan of Maldives

The lack of natural energy resources, coupled with the Maldives’ complete dependance on imported electricity, makes sustainable power solutions imperative. This study examines the design and performance of a renewable energy (RE) system for Gn. Fuvahmulah and L. Gan. A salinity-gradient solar ponds (SGSPs)-based system is proposed to provide power, freshwater, and cooling energy with minimal environmental impact and cost. The RE resources considered include biomass energy, wind turbines (WTs), and flat-plate solar collectors. SGSP power is utilized to produce desalinated water via a humidification–dehumidification (HDH) process, while Rankine cycles operating on biomass generate electricity and supply waste heat for vapor-absorption cooling (VAC). Comprehensive energy, exergy, and economic analyses are conducted using the engineering equation solver (EES) for both wind and solar energy scenarios. The system demonstrates economic viability, achieving levelized costs of electricity (LCOE) of $0.22/kWh with a 2.87-year payback period (PP) at Gn. Fuvahmulah, and $0.16/kWh with a 2.43-year PP at L. Gan. In March, Fuvahmulah attains a peak energetic efficiency of 49.58%, while L. Gan reaches 52.34%. The highest exergetic efficiencies occur in October-25.48% for Fuvahmulah and 22.45% for L. Gan. From a thermodynamic perspective, the system converts nearly half of the input energy into useful outputs, though most of the energy remains low-grade, limiting exergy efficiencies to about one-quarter. This indicates that major irreversibilities occur in the heat-driven subsystems (SGSP, HDH, VAC), while wind and biomass cycles deliver higher-grade electricity. Overall, the design effectively allocates low-grade heat to water and cooling applications and high-grade resources to electricity generation, making it a scalable and sustainable energy model for island communities that ensures long-term energy security.