Optimizing hybrid renewable energy systems for urban sustainability: A case study of five Saudi Arabian cities

Optimizing hybrid renewable energy systems is crucial for addressing urban sustainability challenges globally, especially in regions grappling with energy and water resource constraints. This study focuses on five major Saudi Arabian cities-Abha, Dhahran, Jeddah, Riyadh, and Tabuk-to explore solutions that integrate wind and solar photovoltaic (PV) technologies with storage batteries and grid connectivity. The systems are designed to meet the energy and water demands of a small villa using various multi-stage reverse osmosis (RO) configurations, where water purification efficiency is enhanced through multiple filtration stages. Jeddah's higher winter energy demands require up to 140 PV panels, while Abha's lower energy consumption requires 69 to 80. Dhahran's greater battery storage needs (6-7 batteries) stem from lower solar radiation, whereas Tabuk's abundant solar availability reduces battery requirements (4-5). Grid-connected systems yield the lowest life cycle costs, with Jeddah's grid-connected costs at $87.6k compared to $254.34k for a fully renewable setup. CO2 emissions also decrease from 42.6 tons/year under diesel generators to 7.8 tons/year in the renewable-grid scenario. Increasing the recovery ratio of the RO system from 15 % to 45 % cuts both life cycle costs and environmental impact, while higher feed salinity raises energy demand and costs. Although tailored to Saudi Arabian conditions, these findings and the underlying methodology offer valuable insights for other regions with comparable climatic, economic, or policy settings, thereby informing broader efforts to enhance urban sustainability worldwide.