## 1 Introduction  
Climate warming and pollution are major concerns around the world due to reliance on fossil fuel for energy supply; 82% of the global energy supply using fossil fuel for electricity generation causes 40% of global carbon dioxide emissions. In addition, fossil fuel has the disadvantages of fluctuating prices, transportation difficulties, and finite resources. All these concerns push the world to seek for alternative energy sources that are environmentally friendly and renewable [1]. In this regard the development of renewable resources such as solar, wind, biomass, and hydropower attracts attention to overcome traditional fossil fuel challenges. At the present time, renewable energy occupies 26% of global electricity based on reports of the international energy agency (IEA). In addition, the prospective rate will reach 30% by 2024 with a total installed capacity of 1200 GW, half of which came from solar energy. The IEA expects that solar energy will significantly dominate and can play a major role in jumpstarting the maturity of global renewable energy due to dropping costs and rapid development of photovoltaic (PV) technology, where the costsof solar energy are projected to decline by 15% to 35% by 2024 [2]. The utilization of solar energy is one of the most promising solutions for declining grid power usage and carbon dioxide emission. However, solar energy has its challenges, namely, its intermittent nature and unreliability [3]. To address the first challenge, most of the studies have taken three different approaches. The first approach is integrated with multi-renewable energy sources such as wind or hydro energy for supplementing each other [4; 5; 6; 7; 8; 9; 10]. The second approach is the grid-connected PV system. Combining a PV system with grid power can complement each and deliver constant power to users [11; 12; 13; 14]. The third approach is to develop the use of storage technologies integrated with a PV system in order to supply smooth power to demand. Studies in [15; 16; 17; 18; 19] have revealed different types of storage technology that demonstrate great potential for smoothing the generation of renewable power. Among these different kinds of storage technology, batteries are usually integrated with renewable energy systems for electrifying stand-alone applications [20; 21; 22]. However, the battery storage technology has its limitations such as a short life cycle due to frequent charge and discharge, periodic maintenance that is difficult to undertake in isolated area, and possible environmental harm [23]. Another alternative option is the hydrogen storage system. This kind of energy storage technology has the advantages of long lifetime, high-density energy storage, environmental protection, and lower maintenance cost. Therefore, hydrogen energy storage is the best choice to integrate with renewable energy sources for standalone applications [24; 25], where remote regions are difficult to reach. The combination of a renewable energy system and hydrogen energy storage needs an energy management strategy for scheduling energy from renewable sources to load when the load fully satisfies the excess energy transfer to the hydrogen system in order to produce hydrogen by an electrolyzer through the electrolysis of water to hydrogen and oxygen. A fuel cell (FC) uses hydrogen and oxygen to generate power at the fluctuation period of renewable sources [26]. The integration of PV and FCs has received great attention in recent years. A study by [27] was conducted with six different configurations of microgrid hybrid (PV/wind/battery/FC), and the improved bees algorithm was used to find the optimal design of the six configurations. It was found that hybrid renewable energy based on battery storage was more cost effective than hydrogen energy storage.