Green hydrogen production through water electrolysis offers solutions to renewable energy intermittency & industrial decarbonization challenges. Current global hydrogen production reaches 70 million metric tons annually, predominantly from fossil fuels, while renewable hydrogen represents less than 1 million metric tons. Four primary electrolysis technologies exist: Proton Exchange Membrane achieving 94% efficiency & 99.999% purity but costing $1,000-$2,000 per kilowatt; Alkaline Water Electrolysis offering lower costs at $500-$1,500 per kilowatt but 60-70% efficiency; Solid Oxide & High Temperature Steam methods potentially reaching 80-85% efficiency at elevated temperatures yet facing material challenges. International Energy Agency targets 530 million metric tons annual production by 2050.