An update literature review on trends in optimization techniques used for the design and development of solar photovoltaic–wind based hybrid energy systems is presented. The main objective is to identify latest promising techniques for the optimization of solar photovoltaic (PV)–wind based hybrid systems. Different techniques used by researchers for the optimization of renewable based hybrid energy systems are reviewed along with PV–wind based hybrid system sizing methodology, is presented. Optimization studies during last 2.5 decades by researchers using traditional and new generation methods are analyzed and sixteen optimization methods including hybrid algorithms are presented. The trend shows that new generation artificial intelligence algorithms are mostly used during last decade as these require less computation time and have better accuracy, good convergence in comparison to traditional methods. The study suggests using hybridization of two or more algorithms to overcome the limitations of a single algorithm. Additionally some other techniques are identified for follow up research in the design of PV–wind hybrid systems. This review will be useful for researchers to face complexity and challenges in renewable energy based hybrid system research.