Performance optimization of solar-wind integrated energy system with hybrid energy storage

Abstract

A hybrid energy storage integrated energy system (H-IES) was proposed to simultaneously supply electricity, heating, and cooling to a representative energy consumption center (ECC). The system integrates wind–solar power, a dual-organic Rankine cycle (DORC), an ejector refrigeration cycle (ERC), and thermal/hydrogen/CO₂-based storage. Compared to the conventional ORC, the DORC demonstrates superior thermos-economic performance under high-temperature conditions, with toluene identified as the optimal working fluid. Parametric analysis reveals strong nonlinear and coupled interactions among design parameters, highlighting the necessity of balancing efficiency, cost, and storage scale. Results show that among four metaheuristic algorithms, the grey wolf optimizer (GWO) achieves the highest convergence efficiency and economic benefit (NPV = 122.6 M$). Multi-objective optimization using MOGWO, combined with TOPSIS analysis, yields a robust optimal solution (CC = 0.8292) under varying NPV weightings. Under optimal design case, the system delivers 124.72 GWh annually, with 29.71 % renewable efficiency, 64.63 % energy supply rate, and 99.46 kt CO₂ reduction. By incorporating the energy storage system (ESS), the H-IES effectively mitigates the intermittency of renewable energy, reducing the generation fluctuation rate from 10.31 % to 8.37 %, while keeping the curtailment rate of renewable energy below 1 %. Even under a high discount rate (r = 0.08), the profitability index (PI > 1) confirms the economic viability and investment resilience of H-IES.