Off-grid hydrogen supply from solar or wind sources to hydrogen-based steelmaking can reduce CO₂ emissions. However, the techno-economic feasibility of different supply chain configurations remains uncertain. This study evaluates 61 off-grid hydrogen supply chains for a 15 Mt. steel/year plant in 2030, considering renewable energy sources (onshore/offshore wind, solar, and overseas options), transmission technologies (cables, pipelines, trucks, and ships), storage technologies (compressed gaseous hydrogen, liquid hydrogen, ammonia, methanol, and liquid organic hydrogen carriers), and seasonal storage locations (at the energy source or steelmaking plant). Onshore truck transmission of hydrogen is found to be unpromising due to the significantly higher cost compared to alternative transmission technologies. When the transmission technology is not truck, chains with underground compressed hydrogen storage achieve the lowest levelized cost of hydrogen (LCOH) at 3.8–5.6 €₂₀₂₀/kg H₂, outperforming other options. When underground hydrogen storage is not feasible, liquid organic hydrogen carriers present the next lowest cost. Chains utilizing ammonia, methanol, and liquid hydrogen exhibit lower efficiency, higher renewables capacity requirement, and consequently higher LCOH, making them less attractive. Electricity transmission lowers the LCOH of compressed hydrogen chains compared to hydrogen pipeline transmission, but for other chains the trend is reversed. Hydrogen storage near the steelmaking plant reduces costs by enabling the reuse of boil-off hydrogen in liquid hydrogen chains, but for other chains storing hydrogen near the renewable energy source lowers the cost. Impacts of input uncertainties on the LCOH, limitations of this study, and suggestions for future studies are also presented.

With the demand for anticipated green hydrogen and power production, novel and upgraded catalytic processes are desired for more effective utilization of precious natural resources. Methane steam reforming is an advanced and matured technology for converting methane to hydrogen and syngas. As a renewable energy resource containing a large amount of methane, biogas is a promising fuel for green hydrogen production. Because of the fuel flexibility and high efficiency relative to alternative technologies, solid oxide fuel cells with internal methane reforming capabilities may become an economically viable technology for hydrogen and power generation. A renewed interest in the flexible application of biogas in solid oxide fuel cells for the co-generation of green hydrogen and power has emerged recently, driven by the spectacular advances in fuel cell technology. However, the methane reforming process suffers from inaccurate or unprecise descriptions. Knowledge of the factors influencing the reforming reaction rate on the novel and improved reforming anode catalysts in solid oxide fuel cells are still required to design and operate such systems. Therefore, a comprehensive review of recent advances in methane steam reforming provides meaningful insight into technological progress. Herein, major descriptors of the methane steam reforming reaction engineering are reviewed to provide a practical perspective for the direct application of biogas in solid oxide fuel cells, which serves as an alternative sustainable, flexible process for green hydrogen and power co-production. Current advances and challenges are evaluated, and perspectives for future work are discussed.

The influence of operation temperature, inlet gas composition, current density and the anode thickness on the methane steam reforming reaction over nickel yttria-stabilized zirconia anodes was experimentally studied in solid oxide fuel cells. The experimental results were analyzed using data fitting in Power-Law and Langmuir–Hinshelwood kinetic models. Similar trends of dependence of methane and steam partial pressures were observed in both models. The methane reaction order is positive. Negative influence of steam partial pressure on the methane steam reforming reaction rate are found. The electrochemical reaction and anode thickness affect the reforming kinetics parameters. The anodes thickness shows particular influences on the steam reaction order, and the activation energy when a current is produced. The model evaluation suggests that the two models are comparable and the extra parameters within the Langmuir–Hinshelwood kinetic model are contributing to the lower mean absolute percentage error and higher coefficient of determination R².