Hydrogen Energy: Pathways, Technologies, and Global Prospects for a Decarbonized Future

Abstract

Hydrogen has emerged as a central pillar in global strategies for achieving net-zero emissions, owing to its versatility, scalability, and compatibility with diverse energy systems. As a clean energy carrier, hydrogen can decouple renewable generation from demand, serve as a fuel in hard-to-abate sectors such as heavy industry and aviation, and act as a long-term energy storage medium. This review comprehensively evaluates the state of hydrogen energy, spanning production technologies, storage and transport systems, end-use applications, and techno-economic considerations. Emphasis is placed on green hydrogen from renewable electrolysis, blue hydrogen with carbon capture, and emerging technologies such as turquoise hydrogen via methane pyrolysis. A methodological framework is developed to compare hydrogen pathways based on efficiency, cost, emissions, and scalability. Results highlight the critical role of policy incentives, international hydrogen trade routes, and infrastructure development in driving hydrogen deployment. Discussion underscores challenges of energy losses, water footprint, and material requirements, while the conclusion outlines future research directions and policy priorities for establishing a sustainable hydrogen economy.