Renewable energy integration in desalination: A cost analysis of solar and wind-powered seawater RO system

Water scarcity represents one of the most critical environmental and economic challenges worldwide, especially in arid and semi-arid regions lacking access to reliable freshwater sources. In response, seawater desalination has emerged as a strategic solution to ensure a sustainable and secure supply of potable water for various applications. Among desalination technologies, Reverse Osmosis (RO) stands out for its high efficiency and widespread adoption, primarily due to its relatively low specific energy consumption compared to thermal-based methods. However, high operational costs particularly those related to energy consumption remain a barrier, as most conventional desalination plants rely on fossil fuels, contributing significantly to greenhouse gas emissions and environmental degradation. In this context, integrating renewable energy sources, specifically solar photovoltaic (PV) and wind energy, offers a viable pathway to reduce operational expenditures and minimize environmental impact. Several studies have demonstrated that hybrid renewable energy systems can enhance the sustainability and energy autonomy of desalination plants, aligning with Global Sustainable Development Goals (SDGs). This study conducts a techno-economic analysis of a Seawater Reverse Osmosis (SWRO) plant located in Al Wajh, Saudi Arabia. Detailed Capital expenditures (CAPEX) and Operational Expenditures (OPEX) were estimated for both conventional electricity-based operation and for configurations utilizing solar and wind energy in the same location. An energy simulation model was conducted to determine the optimal number of wind turbines required to maximize energy efficiency while minimizing excess power generation. The analysis revealed that the SWRO powered by renewable energy achieved an energy efficiency of 99%, compared to its conventional electricity-powered counterpart, with an energy surplus of no more than 4%. CAPEX and OPEX cost projections were calculated for both scenarios: conventional grid electricity and renewable energy sources. The findings indicated that the unit production cost per cubic meter of the SWRO plant was 0.59–0.76 $/m3 in the case of grid electricity, whereas it was 0.74–1.12 $/m3 under renewable energy integration. This cost disparity is primarily attributed to the higher CAPEX required for the renewable energy-powered SWRO system, which amounted to 0.28–0.36 $/m3, in contrast to a significantly lower CAPEX of only 0.06–0.09 $/m3 for the electricity-based SWRO configuration. Moreover, artificial intelligence (AI) was employed to support the results and forecast future water demand based on regional climate conditions and consumption patterns. The study concludes with a set of recommendations aimed at optimizing the integration of renewable energy technologies into desalination systems to enhance long-term economic and environmental sustainability.