Status and perspectives of hydrogen role for decarbonising industry: a comprehensive review

This paper aims at providing a broad overview over the last decade on the progress status of hydrogen application for decarbonising the heavy industries. In detail, it deepens and completes the content of previous dedicated sectorial reviews by including hitherto unreviewed aspects as far as possible. To do so, a holistic approach has been used by surveying, in the EU member States as well as worldwide, the current hydrogen demand for hard to abate industry sectors. The knowledge of that need is crucial for identifying the realistic potential substitution of grey hydrogen by the green one. Moreover, the readiness level associated to the direct and the indirect hydrogen-based technologies in the industrial sector, along with technical, environmental, economic features have been analysed. Besides, all the available technologies have been presented and sorted by the thermal processes' temperature level, in which hydrogen can fruitfully take part instead of using electrified systems. In the end, the most relevant theoretical studies and the existing demo sites have been presented. The foreseeable policies and strategies to be implemented in the next future, have been also reported. From this analysis it emerges how the hydrogen direct use is limited to a few applications due to the thermal compatibility with processes and final products quality. Conversely, its exploitation as reactant for producing intermediate chemical compounds or electro fuels seems to be the most suitable and cost-effective strategy in these large-scale energy sectors.