Evolution of the conceptualization of hydrogen through knowledge maps, energy return on investment (EROI) and national policy strategies

• Published in: Clean technologies and environmental policy 2023, Vol.25 (1), p.69-91
• Main Authors: Guevara-Ramírez, Willmer, Martínez-de-Alegría, Itziar, Río-Belver, Rosa María
• Format: Article
• Language: English
• Subjects: Bibliometrics; Biofuels; Biomass; Biomass energy; Biomass energy production; Citations; Clean energy; Climate action; Climate change; Concept formation; Earth and Environmental Science; Energy policy; Energy transition; Environment; Environmental Economics; Environmental Engineering/Biotechnology; Environmental policy; Hydrogen; Industrial and Production Engineering; Industrial Chemistry/Chemical Engineering; Literature reviews; Meta-analysis; Original Paper; Production; Renewable energy; Renewable energy sources; Return on investment; Sustainable Development
• ISSN: 1618-954X; 1618-9558
• DOI: 10.1007/s10098-022-02388-w

In order to address Climate Change and energy dependency challenges, hydrogen (H 2 ) is emerging as a promising energy carrier. Studies related to its production have conceptualized it as green (GH 2 ), clean, renewable (RH 2 ), ecological, and sustainable (SH 2 ). The aim of this research is to deepen the understanding of the GH 2 concept and to state boundaries between different terms. To reach this objective, a bibliometric analysis of publications indexed in SCOPUS is launched. Also, in order to assess the potential of renewable energy sources (RES) for GH 2 production, a review of the meta-analysis literature on the Energy Return on Energy Invested (EROI) ratio as regards these RES is performed. Additionally, an analysis of main national strategies on GH 2 is launched. Results indicate that the GH 2 concept is gaining remarkable relevance, while the keyword maps show no significant differences between SH 2 , RH 2 and GH 2 . EROI reveals low average values for the different biomass energy production processes. For their part, GH 2 national strategies focus mainly on solar and wind technologies, albeit leaving the door open to biomass, where EROI could become an adequate metric to guide these strategies towards a low carbon energy path. Although the role of biomass may become fundamental in this energy transition process, given its low EROI values and considering that it is not a totally clean RES, it should be indexed as RH 2 , but not always as GH 2 . Finally, a proposal that guides a more appropriate use of the term GH 2 is made . Graphical abstract