Pathways and Technologies of Hydrogen Energy: Prospects for Global Decarbonization

Abstract

Hydrogen is increasingly positioned as a keystone of net-zero strategies due to its versatility, scalability, and interoperability across energy systems. As a clean carrier, it can time-shift renewable generation, fuel hard-to-abate sectors such as steel, chemicals, and aviation, and provide seasonal storage. This review surveys the full hydrogen value chain—production routes, storage and transport options, end-use applications, and techno-economics. Particular attention is given to green hydrogen via renewable electrolysis, blue hydrogen coupled with carbon capture, and emerging turquoise pathways based on methane pyrolysis. We propose a comparative framework that evaluates pathways on efficiency, cost, lifecycle emissions, and scalability. Findings emphasize the pivotal influence of policy instruments, cross-border trade corridors, and enabling infrastructure on deployment trajectories. The discussion addresses key headwinds, including conversion losses, water demand, and critical material constraints. We conclude with priorities for research and policy to accelerate a sustainable, globally integrated hydrogen economy.