Trends, challenges, and opportunities in the global green hydrogen value chain: A comprehensive bibliometric and thematic analysis

This paper analyses the 878 Scopus-indexed articles on the global green hydrogen value chain (GHVC) published between 2009 and 2024. The analysis reveals a sharp increase in research activity from 2020 to 2024, in parallel with the rise in global greenhouse gas emissions. The highest average citation rate was 1063, observed in 2013. Leading contributors include Nanyang Technological University and the Federal University of Rio Grande do Norte. At the same time, China and Singapore emerge as the most active countries in research output, particularly in green hydrogen and renewable energy. The International Journal of Hydrogen Energy is identified as the most relevant journal, with Wang Y as the most cited author and the 2013 article by Carmo M as the most cited paper. Notably, China and India exhibit high emissions and high research productivity, indicating no clear linear correlation between emissions and research output. Keyword analysis identifies "hydrogen production" and "green hydrogen" as the most frequently used terms. Thematic analysis identifies ten major research areas: hydrogen production; hydrogen cost and economics; storage solutions; hydrogen as a fuel and energy carrier; integration with renewable energy; sustainability and environmental aspects; policies and legislations; technological advancements; infrastructure development; and market growth and commercialization. These themes are gaining increasing attention. The paper discusses the opportunities and challenges associated with mapping the current landscape and future directions of GHVC research. In conclusion, the article highlights the need to align technology and policy to advance hydrogen and calls for further research to fill knowledge gaps.