Valorization of the by-product oxygen from green hydrogen production: A review

Green hydrogen is regarded as an important pillar in the sustainable energy system of the future. With a constantly increasing speed, new projects of every scale are producing the gas all over the world. Though, the process of electrolysis produces not only hydrogen but eight-times the amount of oxygen. Oxygen is crucial in many applications, however, the majority of the current green hydrogen projects neglect the value of the by-product. In this article, the state-of-the-art of different oxygen production technologies and the usage in today's economy are reviewed. Current studies and projects focusing on the usage of oxygen from electrolysis as well as an outlook on possible developments are presented. It demonstrates the advantages of the utilization of electrolytic oxygen and the increasing interest from governments and industry. A transition from traditional oxygen supply through cryogenic distillation and swing adsorption to electrolytic O₂ can be expected in various cases.