Is the H2 economy realizable in the foreseeable future? Part III: H2 usage technologies, applications, and challenges and opportunities

Energy enthusiasts in developed countries explore sustainable and efficient pathways for accomplishing zero carbon footprint through the H-2 economy. The major objective of the H-2 economy review series is to bring out the status, major issues, and opportunities associated with the key components such as H-2 production, storage, transportation, distribution, and applications in various energy sectors. Specifically, Part I discussed H-2 production methods including the futuristic ones such as photoelectrochemical for small, medium, and large-scale applications, while Part II dealt with the challenges and developments in H-2 storage, transportation, and distribution with national and international initiatives. Part III of the H-2 economy review discusses the developments and challenges in the areas of H-2 application in chemical/metallurgical industries, combustion, and fuel cells. Currently, the majority of H-2 is being utilized by a few chemical industries with >60% in the oil refineries sector, by producing grey H-2 by steam methane reforming on a large scale. In addition, the review also presents the challenges in various technologies for establishing greener and sustainable H-2 society. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.