Abstract
Decarbonizing distributed power generation requires reliable, high-efficiency energy systems capable of continuous dispatch despite the inherent intermittency of renewable resources. This study presents a comprehensive thermodynamic and economic optimization of a hybrid renewable energy plant integrating a concentrated solar power (CSP) central receiver system with an atmospheric bubbling fluidized-bed biomass gasification unit. The integrated architecture drives a high-temperature recompression supercritical carbon dioxide (sCO2) Brayton cycle, designed for a nominal capacity of 10 MWe. Syngas produced from agricultural residue gasification serves as a thermal buffer, firing an auxiliary combustor to maintain a constant turbine inlet temperature of 650 °C during periods of low direct normal irradiance (DNI). A multi-objective non-dominated sorting genetic algorithm (NSGA-II) was employed to optimize the system simultaneously for maximum second-law (exergetic) efficiency and minimum levelized cost of electricity (LCOE). Under baseline conditions, the hybrid configuration achieved an overall thermal-to-electric efficiency of 41.2% and an exergetic efficiency of 37.8%. The Pareto-optimal frontier identified an operational sweet spot with an LCOE of 0.108 $/kWh at an exergetic efficiency of 38.6%, representing a 14.3% cost reduction compared to a standalone CSP plant equipped with oversized two-tank molten salt thermal energy storage. Exergy destruction mapping revealed that the biomass combustor and the solar receiver accounted for 42.1% and 26.5% of total system irreversibilities, respectively. Sensitivity analyses demonstrated that fuel moisture content and solar field aperture area govern the optimal trade-off between capital expenditure and baseload capacity factor, underscoring the thermo-economic viability of hybridized solar-biomass architectures for microgrids and remote industrial power supply.
