# Evaluation of Hydrogen Generation with Hybrid Renewable Energy Sources
## 1 Introduction
### Literature Survey
#### 1.2.4 Electrolysis  
Electrolysis involves the use of electricity to split water into hydrogen and oxygen. The cost of producing hydrogen by electrolysis depends on the cost of electricity and the type of electrolysis technology used. Two main types of electrolysis technologies exist: alkaline water without membrane and alkaline water with proton-exchange membranes (PEMs). Alkaline electrolysis is a mature and relatively inexpensive technology, with production costs ranging from USD 2 to USD 4 per kilogram of hydrogen. PEM electrolysis is a newer and more expensive technology, with production costs ranging from USD 4 to USD 6 per kilogram of hydrogen. An enhancement was achieved in the water electrolysis system by using nickel electrodes, adding a pulsed voltage and magnetic force to improve the hydrogen generation rate when hydrogen was produced by the electrolysis of water, and studying related parameters, such as the effects of magnetohydrodynamics and the potential energy increase [23; 24]. Experiments have shown that the Lorentz force of the magnetic field changes the convection direction of the electrolyte, affecting the flow of bubbles during electrolysis. When a magnetic field is applied, the current density increases by about 15% at room temperature, the distance between the electrodes is 2 mm, and the potential is 4 V. This changes the mass transfer rate at the electrode surface and inside the electrolyte. This reduces the electrochemical polarization of the diffuse layer, further increasing hydrogen production efficiency. With a 10% duty cycle and a 10 ms duty cycle, nearly 88% of the total power was converted, and the current density increased by 680 mA/cm\({}^{2}\), an increase of about 38%. In general, the energetic and magnetic potentials enhance each other when added under an appropriate ground energy and ground potential. Additionally, a static magnetic field (SMF) was applied to water electrolysis to increase the hydrogen yield. However, the influence of a dynamic magnetic field (DMF) on water electrolysis has also been investigated [25]. This study used a DMF to increase the hydrogen yield in water electrolysis. The DMF is generated by rotating a plate-shaped magnet. As a result, the DMF produces 23.1 mL of H\({}_{2}\). This is almost double the 12.1 mL H\({}_{2}\) in the SMF. The DMF increases the likelihood of hydrogen formation by weakening covalent bonds and hydrogen bonds and increasing ion mobility due to additional magnetic field strength. According to the roadmap to achieving a zero-carbon strategy and the previous survey, electrolysis is the most economical and efficient method to produce hydrogen and meet the zero-carbon target. Additionally, electrolysis is the main method for producing green hydrogen. Various electrolysis systems developed for water electrolysis include alkaline water electrolysis (AWE), proton-exchange membranes (PEMs), alkaline anion-exchange membranes (AEMs), and solid oxide water electrolysis (SOE). Different materials and operating conditions are used in these systems; however, the operating principle is the same. Depending on different operating temperatures, low- and high-temperature water electrolysis is also possible. Table 3 shows these methods with different working conditions and characteristics. \begin{table}
\begin{tabular}{l l l l l l l l} \hline \multicolumn{6}{c}{Low-Temperature Electrolysis} & \multicolumn{3}{c}{High-Temperature Electrolysis} \\ \hline  & \multicolumn{3}{c}{Alkaline (OH\({}^{+}\)) Electrolysis} & \multicolumn{2}{c}{Proton-Exchange (H\({}^{+}\))} & \multicolumn{2}{c}{Oxygen Ion (O\({}^{+}\)) Electrophys} \\ \hline Change carrier & OH\({}  
Alkaline water electrolysis is considered the most appropriate method for an electrolysis system to produce hydrogen for many reasons, such as operating at low temperatures (60 to 80 \({}^{\circ}\)C), with aqueous KOH and/or NaOH as an electrolyte; the concentration of the electrolyte is about 20-30%.