## 5 Discussion
### Overall Comparison  
A comparative analysis is performed to evaluate the technical and economic aspects of hydrogen production with wind and geothermal energy (Table 6). In this study, wind power would produce 124.04 tons/MW/yr, while dry steam and single flash geothermal plants would produce 91.92 and 91.96 tons/MW/yr, respectively (Table 6). In addition, the fossil oil barrels saved by dry steam and single flash geothermal power plants would be about 4811.216 bbl/MW/yr and 4809.354 bbl/MW/yr, respectively (Table 6). On the other hand, wind power could save 4540.02 bbl/MW/year. An annual analysis of environmental issues related to wind power performance, including a degradation rate, is presented in Supplementary Table S14. In the present study, the cost of wind-generated electricity is $0.042/kWh. However, the cost of geothermal power in the study area is higher (i.e., $0.086/kWh for dry steam and $0.125/kWh for single flash), probably due to the higher capital cost. This is likely because the study area has a high available wind potential relative to geothermal potential. In other words, the limited data available for geothermal energy in the study area show the difficulties of exploiting this renewable energy, especially due to the very high salinity of the geothermal fluid, which leads to the clogging of geothermal wells ([PERSON], 2016).  
The result of exergoenvironmental modelling showed that the impact index factors of a single flash and dry steam geothermal power plant are about 0.69 and 0.46, respectively (Supplementary Table S15). This indicates a better exergo-environmental performance of the system concerning its unusable waste exergy output and exergy destruction [66]. Furthermore, the improvement in the previous index is estimated to be 1.18 for the dry steam geothermal power plant, while it is 0.45 for a single flash geothermal power plant. This indicates that the dry steam geothermal power plant is more beneficial for the environment (Supplementary Table S15).  
The cost of hydrogen production depends on the amount of hydrogen that renewable energy sources can produce. In this study, it is clear that the use of wind energy results in the lowest cost of hydrogen production ($0.672/kg) compared to the use of geothermal energy. Indeed, the greater amount of hydrogen produced by wind energy compared to geothermal energy, in this case, would probably explain the low cost of hydrogen produced by wind energy. On the other hand, it has been observed for the study area that the investment cost of wind energy seems to be lower than that of geothermal energy. The cost of hydrogen production is estimated to be about $5.80/kg H\({}_{2}\) and $8.16/kg H\({}_{2}\) for dry steam and simple flash, respectively.  
Hydrogen production via electrolysis using renewable energy resources provides a sustainable and environmentally friendly energy solution. The result obtained in the present study is promising and shows that by using renewable energies, such as wind and geothermal energy, it is technically and economically feasible to produce green hydrogen at a low cost at the Asal-Ghoubbet site. However, further research is needed to simulate other green hydrogen production scenarios and to study the interface with other renewable energy sectors.