Mortaza Ahangari Hassas - Department of Electrical Engineering, Tabriz Branch, Islamic Azad University, Tabriz, Iran
Kazem Pourhossein - Department of Electrical Engineering, Tabriz Branch, Islamic Azad University, Tabriz, Iran
Vahid Tamjidi Azad - Department of Electrical Engineering, Engineering Faculty, Azarbaijan Shahid Madani University, Tabriz, Iran

Renewable energy systems will be widespread power sources in future years due to their sustainability and clean nature. Due to intermittent nature of many renewable energy resources (such as wind, photovoltaic and etc.), their hybrid usage are preferred. One of the most important issues related to hybrid renewable energy systems is finding the optimal size of their parts to utilize them efficiently and economically. There are several methods for optimal sizing of hybrid renewable energy systems, reported in many articles, containing their own merits and demerits. In this paper, a comprehensive review of optimal sizing methods for hybrid renewable energy systems have been done. At the end, some of the challenges and future trends in the field of hybrid systems have been discussed. This paper helps the system designers to select the appropriate sizing method for their hybrid renewable energy systems.

Renewable energy; Hybrid system; Sizing methodologies; Hybrid methods