Hybrid renewable energy systems, well-known for their ability to use multiple renewable sources parallelly to supply power, generate significant energy excess to demand. This study optimizes a standalone hybrid renewable energy system (HRES) for Rangabali Upazila, Bangladesh, integrating PV, wind turbines, a diesel generator, and either pumped-hydro storage (PHS) or batteries. The system addresses electricity demand and freshwater production using excess energy. Simulations in HOMER Pro indicate that PHS outperforms battery storage in both economic and environmental aspects. Systems with PHS achieve a net present cost (NPC) of $28.33M and a cost of energy (COE) of $0.175/kWh in both load-following and cycle-charging strategies, compared to $33.57M NPC and $0.207/kWh COE for the systems with battery. Additionally, PHS systems achieve zero emission as they do not require diesel generator operation, while battery systems consume up to 415 L of fuel and emit 1098 kg of CO₂ annually. The results demonstrate that the proposed systems ensure reliable power and freshwater supply, contributing to sustainable development in remote regions. Note: This paper was accepted at ICMIME 2024, organized by Faculty of Mechanical Engineering, RUET. The proceedings were not formally published or assigned a DOI. This version is uploaded as a preprint to ensure open access and proper citation.