Abstarct: A combined system consisting of photovoltaic panels, diesel generators, wind turbines, hydro power, and independent battery storage was examined to meet the energy and water needs in the remote village of Farrokh located in the Qaenat County of South Khorasan Province. The HOMER software was used for modeling and optimization. A multi-criteria decision-making model was employed to prioritize and select strategies, using a questionnaire-baxsed analytic hierarchy process (AHP) approach and pairwise comparisons baxsed on the identified variables. The TOPSIS and fuzzy VIKOR methods were employed for prioritizing strategies and final ranking. The objectives of this study were to reduce the current net present cost, levelized cost of energy, increase the share of renewable energy, and improve system reliability. The main sources of energy generation for the reverse osmosis desalination unit were photovoltaic panels, wind turbines, and hydro power. Additionally, diesel generators and batteries were utilized as backup and storage systems, respectively. The reverse osmosis process for water desalination was also analyzed. The results from HOMER indicated that the first model utilizing solar, hydro, diesel, and battery energy was the best option baxsed on the defined objective functions. However, the higher battery cost resulted in a higher net present cost (NPC), as it stores more energy, in addition to the lowest cost associated with hydro turbines. In terms of the electricity load, it can primarily be supplied by photovoltaic panels and hydro turbines. The highest NPC and COE were related to Case 9. Moreover, the system's renewable fraction (RF) was 79/2% Furthermore, the results from TOPSIS and fuzzy VIKOR methods demonstrated that the combined system of wind turbines, solar energy, hydro power, diesel, and battery was the most suitable. It is evident that the utilization of the combined system reduces the cost of the energy supply system, increases system reliability, and is environmentally friendly. Lastly, the sensitivity analysis was performed on parameters such as the cost of photovoltaic panels, interest rate, battery cost, and fuel cost concerning economic objectives. The results indicated that the combined system with reverse osmosis desalination was sensitive to changes in a 20% interest rate and a 40% cost reduction of photovoltaic panels, as the current net present cost decreased by 11% with a decrease in interest rate and photovoltaic panel cost.