Optimization of a PV–wind hybrid system under limited water resources

Abstract

Water plays a vital role in various economic sectors, including energy production. It is required in various stages of the energy production chain including fuel acquisition, processing and transportation. However, there are growing concerns about the mounting demand for water arising from population and industrial growth, especially in water-stressed regions. Climate change and environmental pollution are exacerbating the situation, and the exploitation of renewable energy resources is perceived as one pillar of mitigating the negative effects of climate change. In this regard, solar photovoltaic (PV) and wind power plants are promising renewable energy technologies, and previous studies have demonstrated that these two energy technologies are less water-intensive. However, the effect of available water on the optimization of a hybrid PV–wind system has not been extensively explored. In this study, a model for investigating water-efficient optimization of PV–wind hybrid systems has been proposed. The demand for water, in the production of energy from PV and wind power plants was expressed as a linear function of the numbers of PV panels and wind turbines. The proposed model was applied to the design of a grid-connected PV–wind hybrid system, using meteorological data from Bonfoi Stellenbosch weather station (33.935°S, 18.782°E) in South Africa. The hybrid system was designed to generate about 100,000MWh/year under the prevailing meteorological conditions. In addition, the Levelized Cost of Energy (LCOE) was optimized with (60,000m3) and without a water constraint. It was found that the water-constrained scenario reduced water demand by 24%. The optimal LCOE of the system declined by 23% when available water was increased from 60,000m3 to 75,000m3. It is therefore concluded that water availability is an important factor in the economic optimization of a hybrid PV–wind system.