Current status, advances, and prospects of research on natural hydrogen

Carbon emissions from fossil fuels pose tremendous challenges to environmental sustainability. Hence, exploring clean energy with low or even zero carbon emissions represents a major scientific issue and technical difficulty in energy research. Natural hydrogen gas (NHG) is considered the ideal clean energy for the future due to its high heating value (HHV), zero carbon emissions, and low price. In this study, we analyze the hydrogen production methods and their trends, the formation and enrichment mechanisms and distribution of NHG, and recent advances in the theories and technologies for determining the formation, tracing, transport, and preservation of NHG. Furthermore, a comprehensive investigation of the novel methods and recent achievements in natural hydrogen exploration across the world lays the foundation to pinpoint critical scientific issues regarding the theory and technology of the formation, preservation, and accumulation of natural hydrogen. It can be concluded that natural hydrogen features substantial resources, various formation mechanisms, complex accumulation processes, and highly risky exploration and development. This necessitates intensified research on fundamental theories and proactive research and development of technologies and equipment for natural hydrogen exploration and development. To this end, we propose an innovative approach of identifying “fairy circles” using remote sensing, determining natural hydrogen sources through geophysical exploration, and delineating exploration targets using geochemical exploration. It is recommended that relevant government departments and industrial sectors actively push forward the study and exploration and development of natural hydrogen by means of supportive policies rolled out, and top-level design strengthened.