# Evaluation of Hydrogen Generation with Hybrid Renewable Energy Sources
## 1 Introduction
### Literature Survey
#### 1.2.4 Electrolysis
It was found that under optimal conditions, the cost of generating 1 kWh of electrical energy with wind turbines was 8 cents cheaper than the market energy unit price when both wind and solar energies were used. [PERSON] and [PERSON] [30] designed a wind-solar system that focuses on hydrogen production and consumption for Dhahran City, Saudi Arabia. According to their findings, the suggested system could independently supply the building's electricity demand and reduce carbon dioxide emissions by 9.6 tons annually. As part of a low-carbon community, [PERSON] et al. [31] developed a hydrogen energy storage system that incorporated a polymer electrolyte membrane electrolyzer, a metal hydride tank, and a proton-exchange membrane fuel cell unit. Notably, this system demonstrated both flexibility and efficiency for long-term and mid-term energy storage, achieving a round-trip efficiency of 52%. In a separate study, [PERSON] et al. [32] investigated hybrid renewable energy systems integrated with buildings in four distinct locations, ultimately leading to the creation of zero-energy buildings. The simulated system, implemented using TRNSYS software, encompassed solar parabolic troughs, wind turbines, and a hydrogen storage unit. According to simulation results, solar systems and wind turbines could, respectively, produce 35% and 49% of the electricity required by buildings in each city, noting that solar energy is significantly less effective than wind energy for storing hydrogen during the winter. However, renewable resources and hydrogen storage systems had the potential to generate 70% to 88% of the electricity needed by buildings. Another study conducted by [PERSON] et al. [33] utilized TRNSYS software to assess the potential, storage, and consumption of electricity in Saskatoon, Canada, a city with high solar and wind power potential. The findings suggested that solar panels had a considerably higher energy generation capacity, indicating their superior potential compared to wind turbines. To examine the transient behaviour of a residential energy system, [PERSON] et al. [34] developed a model using TRNSYS software to fulfil the heating, cooling, domestic hot water, and electricity demands of a residential building. This study also presented comparative analyses of hydrogen fuel cells and conventional batteries. Based on the results, HVAC systems utilizing hydrogen storage had a capital cost twice that of systems using batteries. Nevertheless, employing hydrogen storage systems with larger capacities resulted in improved performance. [PERSON] et al. [35] put forward and thoroughly investigated an innovative strategy to effectively combine solar and wind energy sources through hydrogen storage. The goal was to enhance grid stability and reduce peak loads. The study utilized the Transient System Simulation (TRNSYS) tool and the Engineering Equation Solver program to perform a comprehensive assessment of the techno-economic and environmental aspects of a residential building in Sweden. A four-objective optimization, employing MATLAB with the grey wolf algorithm and an artificial neural network, was employed to find the optimal balance among various indicators. The results indicate that, under optimal conditions, there is an 80.6% improvement in primary energy savings, a 219% reduction in carbon dioxide emissions, a cost of 14.8 USD/h, and a purchased energy amount of 24.9 MWh. The analysis of the scatter distribution suggests that maintaining the fuel cell voltage and collector length at their minimum values is crucial, while the electrode area is not a significant parameter. The proposed renewable-driven smart system is capable of meeting 70% of the building's energy needs throughout the year. Additionally, excess energy can be sold back to the local energy network, making this system a practical and viable alternative. [PERSON] et al. [36] introduced and assessed a novel solar-based system that featured an Alkaline Fuel Cell (AFC) and an electrolyzer.