In response to the escalating threats of climate change and the urgent need to reduce greenhouse gas emissions, the global energy system is undergoing a profound transition and transformation. In this context, hydrogen (H₂) has emerged as a versatile and promising energy carrier, possessing the capacity to decarbonize sectors where direct electrification remains challenging, including the steel industry, chemical manufacturing, ammonia production, and heavy-duty transportation. Despite decades of technological development, the widespread implementation of hydrogen-based energy systems continues to face technical, economic, and infrastructural barriers. This comprehensive review examines various hydrogen production methods, including grey, blue, green, turquoise, pink hydrogen, as well as emerging types such as gold and orange hydrogen. The projected demand for hydrogen, current cost structures, and key strategies for technology deployment are systematically investigated. Furthermore, this study addresses environmental challenges and research needs related to pollutant emissions, water consumption, and life-cycle sustainability. By synthesizing current trends and future perspectives, this article emphasizes the critical role of hydrogen in the global energy transition and outlines pathways to overcome the barriers hindering its large-scale deployment. It is highlighted that green hydrogen can lead this transition in the long term, provided that conflicts over water consumption and land use in arid regions are properly managed, whereas blue hydrogen offers a temporary bridge solution by leveraging existing infrastructure.
Talebian S H, rostampour S H, tanhaei P. A Comprehensive Review of Hydrogen Pathways in the Context of Energy Transition Strategies. IJE 2026; 28 (3) :14-38 URL: http://necjournals.ir/article-1-1992-en.html