Hydrogen Energy as Sustainable Energy: A Comprehensive Review

Hydrogen is increasingly recognized as a cornerstone of the global transition toward a low-carbon and sustainable energy system. This review synthesizes recent advances across the hydrogen value chain—from production and storage to utilization and policy—while highlighting the opportunities and challenges shaping its large-scale deployment. We compare the main production routes, including reforming, gasification, and electrolysis, with particular attention to green hydrogen derived from renewable energy. Advances in storage technologies, such as compressed, liquid, and solid-state systems, are critically assessed in terms of efficiency, safety, and scalability. The analysis extends to hydrogen’s emerging roles in hard-to-abate sectors including industry, heavy transport, and power generation. By integrating technical, economic, and policy perspectives, this review provides a holistic understanding of hydrogen’s transformative potential in achieving deep decarbonization. We identify key research and investment priorities required to accelerate the realization of a secure and equitable hydrogen economy.