Hydrogen production from renewable energies - electrolyzer technologies

Water electrolysis represents one of the simplest approaches to produce hydrogen and oxygen in a zero-pollution process by using electricity for the electrochemical decomposition of water. Three main technologies can be distinguished according to the electrolyte used in the electrolysis cell: alkaline electrolysis with a liquid electrolyte, proton exchange membrane electrolysis with an acidic ionomer, and high-temperature steam electrolysis with a solid oxide as the electrolyte. In this chapter a general overview of these three technologies and their main characteristics are given. Choice of materials, cell concepts, and system layouts will be introduced and discussed. Drawbacks and advantages in terms of coupling with renewable energy sources will be considered for each technology. Finally, an overview of manufactures and cost issues are presented.