Hydrogen—The New Energy Vector for the Transition of Industries "Hard to Abate"

Dear Colleagues,

The industrial sector accounts for the largest share of global energy consumption. Given a continuously increasing demand for industrial products, the key for industrial decarbonization is decoupling its production from the produced CO₂ emissions. The replacement of traditional energy production based on carbon sources with renewables is insufficient for the inversion of global warming. A major transformation and redesign of the global energy system is required towards decarbonisation and to achieve the Paris Agreement targets. This Grand transition is a complex and pressing issue, where global joint efforts and system solutions are essential; with hydrogen being one of them.

The present Topic aims to describe hydrogen properties as crucial energy vectors of the future. Present hydrogen production routes and methods of utilization will be underlined. Hydrogen will become a crucial energy vector and the other leg of the energy transition alongside renewable electricity by replacing coal, oil, gas, and conventional hydrogen across different segments of the economy. As an energy carrier, hydrogen’s versatility will be underlined as a key actor in decarbonization. Its energy storage capability during renewable production peaks is a crucial factor of its potential introduction in many civil and industrial sectors. Obviously, this depends on its “color”, which influences the new acceptability because of the major or minor weight of traditional carbon sources. As a matter of fact, the largest amount of attention will be devoted at the so called “green hydrogen” production route, which is based on renewables or on carbon-free power sources. Among the main civil and industrial applications, the role of hydrogen for the “hard to abate” industry decarbonization will be largely emphasized.

Hydrogen storage in innovative materials will be reviewed as a great solution for large scale production. In the present issue, the production routes based on hydrocarbons or clean sources will be also reviewed and compared. The properties of hydrogen as an energy carrier that is useful for the efficient reduction of iron ores will be described in the present issue. The basic mechanisms related to the direct reduction of iron ores through hydrogen will be detailed and analyzed. The kinetic analysis of hydrogen metallurgy in a wide range of conditions will be reviewed. Thermodynamic analysis in various gas mixture conditions employed during iron ore reduction will be detailed. A large amount of attention will be devoted to the energy efficiency of the reduction processes as a function of the different reducing gases that are employed. All of the previous factors will be described from the macro to the atomic scale.

The hydrogen production from non-renewable sources continues to grow all around the world because of the continuous need for such energetic vectors in modern industry. The decomposition of basic hydrocarbons for t hydrogen synthesis will be described in the present issue. First of all, the coal gasification procedure and reactors will be reviewed. Steam reforming and syngas production will be described in depth. The process performance will be analyzed and compared to those belonging to traditional conventional routes.

The decarbonization of human activities requires that hydrogen be produced through sustainable routes. One of the most promising ways to achieve this is through the electrolysis of water with the energy sources provided by renewables. The main available technologies that are available for hydrogen production through electrolysis will be reviewed in the present issue. The fundamentals of water electrolysis will be described. The problematics related to the desalinization and purification of sea water for its employment in water electrolyzers will be described. The fundamental aspects related to the choice of high-temperature or low-temperature technologies will be analyzed. The key aspects of the integration of water electrolysis with renewable sources will be discussed.

Hydrogen production and storage are the main issues related to its large-scale utilization. The large-scale implementation of water electrolysis for the production of green H₂ has mainly been hampered by cost issues. In the present issue, the main costs issues that are related to the hydrogen economy transition will be analyzed. The fundamental aspects of hydrogen production costs by each route will be highlighted. The forecasts related to new energy solutions for hydrogen production will be analyzed. The economic issues related to hydrogen production to direct reduction reactors will be underlined.

Prof. Dr. Pasquale Cavaliere
Prof. Dr. Geoffrey Brooks
Topic Editors