Status on Technologies for Hydrogen Production by Water Electrolysis

The electrochemical production of hydrogen by water electrolysis is a well-established technological process worldwide dating back more than 100 years. Since the cost of producing hydrogen by this method is currently higher than that of producing it from fossil energy carriers such as natural gas and coal, at present only about 4% of hydrogen requirements are covered by electrolysis. However, hydrogen is envisaged as a more or less important storage medium or energy carrier for transportation purposes in future energy systems where renewable energy sources are to play a major role in the energy mix. This chapter describes the basic physical and technical principles and the state-of-the-art of the different electrolysis processes such as alkaline electrolysis, polymer electrolyte membrane (PEM) electrolysis and high-temperature electrolysis. In addition, the challenges and the need for research and development for alkaline and PEM electrolysis are identified so that water electrolysis can be realistically and sustainably applied in the mass markets after 2020 for hydrogen production using surplus electricity generated from renewable sources.