Green hydrogen (GH) is considered one of the best environmental alternatives fuel in the coming decades. GH is produced from natural solar energy and water resources. Although water is available in most countries, but sun is restricted in some regions along the year. Electrolysis process has a potential technology for clean and sustainable source of energy. It is also the best alternative to produce valuable hydrogen fuel (HF) from solar energy. The current study presents a theoretical analysis of designing a small-scale hydrogen generation unit containing two electrolyzers with 100 cells and 40 cm plate diameter to produce 75 kgH2/day with consumed electric energy of 3360 kWh and 675 liter water/day, respectively. For designing a large-scale hydrogen generation plant with 280 ton/day (102,200 ton/year), the required electric power can be estimated as 618,333 kW (618.3 MW). Consequently; the electric energy consumption in MWh required can be estimated as 14,840 MWh and the required daily water consumed in m3/day can be estimated as 2,520 m3/day. Considering the price of 1.0 kg of GH equals 3 USD, the cash flow diagram, showed that the project can recover the invested budget (2,259,390,903 USD) within 8 years and earn a remarkable profit of 5,115,728,534 USD after 25 years. This means that the investment in green hydrogen production projects is highly profitable as hydrogen can be sold as direct fuel, energy carrier or to be reacted with nitrogen to produce green ammonia where can be utilized as fertilizers and other useful industrial applications