The electrolyte and separator depend on the type of electrolyser, with alkaline electrolysers (AEL) using aqueous potassium hydroxide as the electrolyte and a hydroxide-conducting diaphragm as the separator, proton exchange membrane electrolysers (PEMEL) using a polymer electrolyte membrane as both the electrolyte and separator and solid oxide electrolysers (SOEL) using oxide-conducting ceramics as both the electrolyte and separator at high temperatures. The two electrodes are separated by a semi-permeable material that suppresses mixing of the two product gases but allows for the migration of certain ions to maintain charge balance.

In electrolysers, a DC voltage applied between two electrodes in contact with an electrolyte splits water into H 2 and O 2.

Due to their lower TRL and requirement for a light source, large-scale photocatalysis and photoelectrochemistry testing are less developed and the requirements are currently less predictable.Īmong these, EL is by far the most established technology with fundamentals of electrolysis dating back more than two centuries. Choosing the right location is crucial not only for meeting these device requirements, but also for improving financial viability through supplying affordable electricity and providing a remunerated H 2 sink to offset the testing costs. Key aspects to be considered are the electricity and utility requirements of the devices under testing, the analysis of the produced H 2 and O 2 and the safety regulations for handling large quantities of H 2. This perspective highlights the challenges to be met on the path to implementing a test facility for large-scale water electrolysis, photoelectrochemical and photocatalytic water splitting and aims to serve as a much-needed blueprint for future test facilities based on the authors’ own experience in establishing the Hydrogen Lab Leuna. Testing these hydrogen technologies on the MW scale requires the development of dedicated new test facilities for which there is no precedent.

Green hydrogen is set to become the energy carrier of the future, provided that production technologies such as electrolysis and solar water splitting can be scaled to global dimensions.

Off the record by ka linde