This chapter deals with the production of hydrogen via electrolysis, assessing and discussing its production pathways (alkaline water electrolysis, polymer electrolyte membrane or solid oxide electrolysis) from a chemical and technical point of view. Electrolytic hydrogen is the subject of ever-increasing scientific research as it is considered one of the keys to sustainability in the energy, industry and mobility sectors. For this reason, ample space is given in this chapter to green hydrogen, analysing the problems resulting from the use of intermittent and impossible to program renewable energy both from a technical and from an environmental and economic point of view. The aspect of the environmental impacts of electrolytic hydrogen is tackled with a life cycle assessment approach, also taking into consideration the impacts of production. Similarly, an economics assessment was performed on the basis of scientific literature comparing the levelled cost of hydrogen of different solutions, so that not only capital investment and energy costs are considered, but also the environmental and health externalities tied to the supply of energy.