Numerical assessment of a hybrid energy system based on solid oxide electrolyzer, solar energy and molten carbonate fuel cell for the generation of electrical energy and hydrogen fuel with electricity storage option

In recent years, due to increasing energy requirements and special attention to the issue of carbon, hydrogen fuel has become an efficient alternative to energy carriers. The aim of this article is to present and investigate of a novel solar-driven hydrogen generation process. The introduced hybrid energy system (HES) is comprised of a solid oxide electrolyzer (SOE), solar photovoltaic (SPV) modules, and solar dish collectors (SDCs). Further, since one of the most attractive utilizations of hydrogen fuel is as a fuel cell's fuel, the present HES suggests that hydrogen fuel be injected into molten carbonate fuel cell (MCFC) to convert it into useful electrical and thermal energies. Finally, the electrical energy obtained from HES is stored via a relatively new hybrid storage system (i.e., pumped hydro and compressed air (PHCA) storage system) for peak and night hours. Therefore, the considered HES in the present study can generate electrical and thermal power, hydrogen fuel and oxygen gas, and store electricity. Although some publications on solar-driven hydrogen generation process are available, there is no study on proposed HES of the present article that considers both energy production and storage. In other words, the components embedded in the proposed HES are developed in such a way that the relationships between them are novel. According to the numerical simulation, it was found that the electrical energy production rate and electrical efficiency of HES are almost 183.1 kWh/day and 33.6 %, respectively. HES can also produce approximately 3.9 kg of hydrogen fuel per day. Moreover, the storage system size for storing the electricity yielded from the considered HES should be nearly 29.9 m3 (at n = 1.2). Also, the storage efficiency of the energy cycle is 59.1 %. The considered process is investigated under different effective parameters in order to identify their effectiveness.