This presentation focuses on the engineering challenge of large-scale hydrogen production under variable renewable power and examines how alkaline electrolysis systems can balance dynamic response, stable hydrogen supply, and manageable operation and maintenance while supporting the scale-up of green fuel projects. The discussion will draw on HydoTech’s industrial experience in renewable hydrogen and green fuel applications, with particular reference to its participation in the world’s largest green methanol project, which supplies green methanol to the Maersk shipping fleet and has achieved green hydrogen production costs of USD 2/kg in project practice. The talk will cover key technology pathways for large-scale flexible hydrogen production, system integration, and project implementation, and will also offer observations on the industrialization of green methanol, SAF, and other green fuels, including technical constraints, economic boundaries, and future development trends.