Hydrogen and medical oxygen by renewable energy based electrolysis: A green and economically viable route

As emphasised by the crisis caused by the COVID-19 pandemic, medical oxygen is an essential health commodity. The purpose of this study is the application of Renewable Energy Sources (RES)-based (photovoltaic-powered) water electrolysis plant for oxygen production in hospitals to self-produce the amount of oxygen they need, and - in particular - to define when this choice could be economically competitive with the current medical gas market. The proposed plant is able to produce oxygen and to store energy in hydrogen form at the same time, proposing a new approach in RES applications. Therefore, we calculated as a function of the hospital size (number of beds, up to 500) what should be the market price of oxygen above which the self-production of oxygen is economically profitable (assuming a break-event point of 15 years). Hydrogen is considered a by-product allowing to increase the system efficiency and supplying extra services. The results demonstrated that, assuming a selling price of 3 EUR/kg for the hydrogen (co)-produced by the plant, the on-site production of medical oxygen could be an interesting alternative compared to purchasing from the local gas resellers, if its market price is higher than 3-4 EUR/kg. Since this value is in line with current prices established for ex-factory oxygen by some national regulatory authorities (e.g., AIFA), we can conclude that the proposed RES-based electrolysis system is a green and economically feasible solution for oxygen production in hospitals, able also to increase hospital resilience against energy and oxygen shortage.