Hydrogen supply chain: Current status and prospects

In the current world energy scenario with rising prices and climate emergencies, the renewable energy sources are essential for reducing pollution levels triggered by carbon-based fuels. Hydrogen rises in the world energy scenario as an important non-carbon-based energy able to replace fossil fuels. For this reason, the rapid development of hydrogen-related technology has been seen in recent years. This review paper covers hydrogen energy systems from fossil fuel-based hydrogen production, biomass and power from renewable energy sources, to hydrogen storage in compressed gases, liquefied and solid materials, and hydrogen-based power generation technology. It represents a quiet complete set of references that may be effective in increasing the prospects of hydrogen as a fuel in the coming years. The main conclusions drawn are that natural gas and coal supply nearly all of the current hydrogen. The commercially available technologies for hydrogen production are steam methane reforming, partial oxidation, and alkaline electrolysis. The most economical methods for hydrogen production are partial oxidation, steam methane reforming, coal gasification, and biomass gasification. Metallic cylindrical reservoirs are the most promising alternative to underground storage of compressed hydrogen at large scales. Some metal compounds and composites can store a significant amount of hydrogen while maintaining reasonable adsorption and desorption kinetics. The transportation sector is likely to see widespread use of hydrogen in the future, helping to reduce pollution. Vehicles can be powered by fuel cells, which are much more efficient than internal combustion engines. There are still several obstacles in the way of widespread hydrogen utilization. The first one is that the cost of producing hydrogen from low-carbon sources is elevated. As the cost of renewable energy declines and hydrogen production is scaled up, it is anticipated that the hydrogen production costs would decrease over the next years. Innovative technologies are expected to increase the interest on thermochemical hydrogen production to massively substitute electrochemical technologies since they are theoretically cost-effective. More research is needed to fix concerns with some of the thermochemical cycles in order to rise its maturity. Increasing the chemical reaction conversion ratios, which can be resolved utilizing nonequilibrium reactions, is one of them. The transportation sector is likely to see extensive use of hydrogen in the future, helping to reduce carbon dioxide emissions. The power required by vehicles may be supplied by fuel cells, which are more efficient than internal combustion engines.