Hydrogen Production From Steam–Methane Reforming and Electrolysis: A Comprehensive Review of Conventional and Solar‐Powered Technologies

This review provides a systematic and technically detailed analysis of hydrogen (H 2 ) production via steam–methane reforming (SMR) and water electrolysis, with particular emphasis on the integration of solar energy to enhance sustainability and reduce carbon intensity. The two main technologies under scrutiny are SMR and water electrolysis, which play critical roles in H 2 production globally. While SMR dominates current production methods (conversion efficiencies of 65%–85%), contributing to a large percentage (up to 48%) of the world’s H 2 supply, its significant carbon emissions (upto 9–12 kg CO 2 per kg H 2 ) is a major drawback. On the other hand, water electrolysis, when driven by renewable energy sources (RESs) like solar power, offers a cleaner alternative, producing H 2 (up to 4%) with minimal carbon footprint. The review highlights innovations in incorporating solar energy into SMR and electrolysis processes, notably through concentrated solar power (CSP) and photovoltaic (PV) technologies, which enable the use of solar heat for endothermic reactions, thereby reducing dependency on traditional fossil fuels and reduces CO 2 emissions by 20%–40%. Additionally, hybrid energy systems that combine solar with other renewable sources are discussed as a solution to the inherent intermittency of solar power, ensuring a more stable and reliable H 2 production process (with overall efficiencies of ~21%). Electrified SMR (E‐SMR) achieves thermal efficiencies up to 97.27% and reduces H 2 production costs to USD 2.47/kg. The paper also explores the economic and environmental benefits of these solar‐powered systems, such as the potential for significant carbon emission reductions, long‐term financial savings, and the increasing viability of carbon credit markets. Technological advancements such as advanced catalysts, improved reactor designs, and thermal storage solutions are also examined for their potential to enhance the efficiency and scalability of solar‐powered H 2 production. Case studies and industrial applications from regions rich in solar resources are presented, illustrating the practicality and economic feasibility of these technologies. This review concludes that the convergence of advanced solar–thermal and PV technologies with improved reactor engineering and hybrid energy management offers a technically and economically feasible pathway towards large‐scale and low‐carbon H 2 production, positioning solar‐integrated systems as a critical enabler of the global clean energy transition.

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