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As part of global decarbonization efforts, hydrogen has emerged as a key energy carrier that can achieve deep emission reductions in various sectors. This review critically assesses the role of hydrogen in the low-carbon energy transition and highlights the interlinked challenges within the Techno-Enviro-Socio-Political (TESP) framework. It examines key aspects of deployment, including production, storage, safety, environmental impacts and socio-political factors, to present an integrated view of the opportunities and barriers to large-scale adoption. Despite growing global interest, over 90 % of the current global hydrogen production originated from fossil-based processes, resulting in around 920 Mt of CO 2 emissions, two-thirds of which were attributable to fossil fuels. The Life Cycle Assessment (LCA) shows that coal-based electrolysis resulted in the highest GHG emission (144 - 1033 g CO 2 -eq/MJ) and an energy consumption (1.55–10.33 MJ/MJ H 2 ). Without a switch to low-carbon electricity, electrolysis, cannot deliver significant climate benefits. Conversely, methanol steam reforming based on renewable feedstock offered the lowest GHG intensity (23.17 g CO 2 -eq/MJ) and energy demand (0.23 MJ/MJ), while biogas reforming proved to be a practical short-term option with moderate emissions (51.5 g CO 2 -eq/MJ) and favourable energy figures. Catalytic ammonia cracking, which is suitable for long-distance transport, represents a compromise between low energy consumption (2.93 MJ/MJ) and high water intensity (8.34 L/km). The thermophysical properties of hydrogen, including its low molecular weight, high diffusivity and easy flammability, lead to significant safety risks during storage and distribution, which are exacerbated by its sensitivity to ignition and jet pulse effects. The findings show that a viable hydrogen economy requires integrated strategies that combine decarbonised production, scalable storage, harmonised safety protocols and cross-sector stakeholder engagement for better public acceptance. This review sets out a multi-dimensional approach to guide technological innovation, policy adaptation and infrastructure readiness to support a scalable and environmentally sustainable hydrogen economy.
Anekwe et al. (Thu,) studied this question.