Comparative assessment of battery and pumped hydro storage for renewable-powered reverse osmosis desalination in Saudi Arabia

This study presents a comparative techno-economic and environmental assessment of battery and pumped hydro storage (PHS) for powering renewable-driven reverse osmosis (RO) desalination systems in Saudi Arabia. Ten coastal locations along the Red Sea were evaluated to identify the most cost-effective and sustainable configurations under local climatic conditions. A hybrid photovoltaic–wind (PV–WT) generation framework was developed, integrated with either battery or PHS storage, and optimized using the Artificial Rabbit Optimization (ARO) algorithm under single-objective (minimizing Levelized Cost of Water, LCOW) and multi-objective (minimizing LCOW and Annual Carbon Emissions, ACE) formulations. Results indicate that PV-based configurations consistently outperform WT-only systems in both cost and reliability due to superior solar availability. The site-averaged LCOW for PV and PV/WT systems was 1.73 $/m³ with battery storage and 1.90 $/m³ with PHS, while the PV/WT/Diesel hybrid achieved 1.13–1.14 $/m³ under single-objective optimization. Multi-objective results show that PHS achieves 20–35 % lower ACE across all cases for only a 7–10 % cost increase compared with battery storage. Among renewable-only designs, PV + PHS provided the most balanced cost–emission performance, whereas PV + WT + Diesel with PHS delivered the most economical abatement per ton of CO₂ avoided.