The conventional supply of hydrogen takes place via the fossil resources natural gas or coal. An alternative is water electrolysis, which uses an electric current to split water into hydrogen and oxygen. When using renewable electricity, one speaks of green hydrogen. Water electrolysis consists of individual very flat cells in which the electrochemical process takes place. Several of these cells are stacked into so-called stacks and interconnected in an efficient overall system with units for water supply and gas discharge. Water electrolysis is currently entering the market. The first large-scale plants already exist nationwide.
Various types of water electrolysis and related systems are researched and improved in the HYPOS topic of chemical conversion. In addition to PEM, alkaline and high-temperature electrolysis, other types of electrolysis such as reversible membrane electrolysis or chlor-alkali electrolysis are also researched at HYPOS: