Hydrogen as a sustainable energy carrier: A review of production, storage, and utilization technologies

Hydrogen has become a pivotal component in the global pursuit of carbon neutral and sustainable energy systems owing to its high-gravimetric energy density, fuel flexibility, and cross sectoral applicability. This review provides a comprehensive analysis of contemporary hydrogen technologies encompassing production, storage, and utilization, with an emphasis on their scientific principles, material innovations, and engineering challenges. Major production pathways, including water electrolysis, thermochemical and photoelectrochemical splitting, biomass derived routes, and emerging solar-driven hybrid methods, are critically evaluated with respect to energy efficiency, techno economic trends, and integration potential with renewable resources. Advances in hydrogen storage are examined across compressed, liquefied, and solid state systems, highlighting progress in metal hydrides, carbon-based porous media, and nanostructured materials that promise enhanced safety, reversibility, and storage density. Utilization technologies such as proton exchange membrane (PEM) and solid oxide fuel cells, direct hydrogen combustion systems, and hybrid power modules are reviewed with attention to catalytic performance, thermal stability, degradation pathways, and system level optimization. Additionally, cross cutting issues including lifecycle emissions, infrastructure readiness, safety protocols, and the role of hydrogen in sector coupling are assessed to outline broader deployment challenges. The review concludes by identifying future research opportunities in advanced materials design, artificial intelligence enabled process optimization, and circular economy strategies aimed at accelerating hydrogen's role as a foundational pillar of next generation clean energy systems. Representative hydrogen production technologies exhibit efficiencies ranging from ∼60%–85% for water electrolysis, hydrogen purity above 99.9% for PEM electrolysis, and production costs that typically range from about USD 3–8 kg−1 for green hydrogen depending on electricity price and technology. These comparisons indicate that while green hydrogen offers superior environmental performance, further improvements in efficiency, cost reduction, and technology maturity are required for widespread commercialization.