Optimal planning of a 100% renewable energy island supply system based on the integration of a concentrating solar power plant and desalination units

Environmental-unfriendly power supply mode and freshwater shortage are two main problems for isolated islands. A 100% renewable energy supply system equipped with local desalination units is an effective solution to the above problems. It can save fuel supplies and eliminate pollutant emissions. Firstly, a 100% renewable energy supply system based on wind turbines and the integration of a concentrating solar power (CSP) plant and desalination units is proposed in this paper. The flexible schedulability of CSP plants is utilized to complement to wind power generation, and the thermal storage system reduces the battery energy storage configuration for islands. Different from the conventional method of seeking the minimum levelized cost of CSP from limited capacity combinations, an optimal planning model is established to achieve the minimum overall costs of the 100% renewable energy system. In addition, the adjustable output characteristic of CSP is also considered as the decision variables to optimize the operation of the microgrid. The model is linearized to a mixed integer linear programming problem. Simulation results show that the proposed supply system improves the efficiency of renewable energy utilization and capacity factors of generation units; the peak load demand is cut down and the capacity configuration of generation units is also reduced. The comparison with other state-of-art systems shows that the cost-effectiveness of the proposed system is better in areas with abundant renewable energy resources and high fuel costs.