In order to fulfil the rising demand for water, particularly in areas with a lack of freshwater resources, reverse osmosis (RO) desalination has emerged as a popular desalination technique. The environmental impact of carbon emissions from conventional fossil fuel energy sources is lessened by its integration with renewable energy sources (RES). This system is called hybrid energy system (HES). HRS-RO desalination system is being optimized primarily to lower overall system costs and energy requirements and to ensure system dependability.This paper presents investigation of the hybrid energy system- HES-RO desalination system's optimization based on ideal system operation, ideal system sizing, and ideal thermodynamic analysis. Hybrids desalination techniques were taken into consideration alongside RES. Discussions on the review's key results and suggestions for additional research were offered. The most significant studies showed that of energy (COE) of HES is between 0.179 $/kWh and 0.272 $/kWh, LPSP is 0.1397 and Renewable fraction (RF) of 92.