Multi-objective optimization of a photovoltaic-wind- grid connected system to power reverse osmosis desalination plant

Utilizing fossil fuel for powering desalination plants is associated with release of greenhouse gases emissions to the atmosphere. Alternately, renewable energy sources are clean and environmentally friendly. This paper develops a multi-objective model based on mixed-integer programming approach to size a grid-connected Photovoltaic-wind system. The model objectives consider the economical aspect by minimizing the total life cycle cost, and the non-economical aspects by reducing the greenhouse gas emissions and the grid contribution share. The hybrid system covers the energy demand of a Reverse Osmosis desalination plant that is used to supply fresh water to a residential area in Saudi Arabia. The model generates a set of Pareto-optima solutions from which decision-makers can choose according to their preferences. Three plans are selected from the Pareto-optima solutions to show the exchangeability between the renewable energy system and the grid. For instance, with 100 photovoltaic modules and 94 wind turbines, the system can supply 18% of the plant's energy requirements while emitting the least amount of carbon dioxide (90,899 kgCO2-eq/yr). Furthermore, the energy cost is 0.0557 $/kWh, which is less than the cost of kWh purchased from the grid. The main findings and managerial insights are analyzed from economic and environmental perspectives. •A hybrid solar-wind-grid system to power a reverse osmosis plant is proposed.•Multi-objective mixed-integer optimization model is formulated to size the system.•Pareto-optima solution is generated under different perspectives.•Using renewable energy in reverse osmosis is economical and environmentally viable.•Greenhouse gase emissions can be cut by 71% compared to current practice.