Three decades of hydrogen energy research: a bibliometric analysis on the evolution of green hydrogen technologies

Abstract

Hydrogen energy is a crucial enabler of a low-carbon future, playing a significant role in sustainable energy transitions and contributing to SDG 7 (Affordable and Clean Energy) and SDG 13 (Climate Action). As the global energy landscape shifts towards decarbonization, green hydrogen—produced through renewable energy-powered electrolysis—has emerged as a key solution to mitigate carbon emissions and reduce dependency on fossil fuels. However, challenges such as high production costs, energy-intensive processes, and the need for efficient storage and transportation infrastructure continue to hinder its widespread adoption. This bibliometric review systematically examines three decades of hydrogen energy research, with a particular emphasis on the evolution of green hydrogen technologies. Unlike previous studies, this work integrates bibliometric analysis with thematic clustering to provide a comprehensive perspective on research trends, technological advancements, and interdisciplinary collaborations within the field. Drawing from SCIE and SCOPUS databases (1990–2023), a total of 6536 publications were analyzed using key bibliometric indicators, including Impact Factor (IF), h-index, Total Citations (TC), and Citations per Article (CPA). The study identifies leading research hubs, key contributors, and emerging research themes, highlighting the role of renewable energy-driven hydrogen production, advancements in hydrogen storage, and the growing intersection between biohydrogen and sustainable energy solutions. Our findings reveal a significant rise in research on green hydrogen technologies, driven by policy incentives, technological breakthroughs, and global sustainability commitments. Despite these advancements, critical gaps remain in improving cost efficiency, scaling up production, and enhancing storage solutions for green hydrogen integration into energy systems. This review provides strategic insights for addressing these challenges by fostering global research collaboration, interdisciplinary approaches, and policy-driven technological development. Ultimately, the study serves as a valuable roadmap for accelerating the transition towards a green hydrogen economy, reinforcing its role in shaping a sustainable and decarbonized future.