Hydrogen fuel cells

In a hydrogen fuel cell, the energy contained in the hydrogen is converted into electrical energy. This is done by catalysis (decomposition of the hydrogen into protons and electrons). There are two electrodes inside the fuel cell: an anode and a cathode. Hydrogen is fed to the anode, and in the process the hydrogen oxidises, giving off electrons to form protons. When the positively charged hydrogen protons react with oxygen, water vapour is produced, which is discharged back into the environment as "exhaust gas". The negatively charged electrons flow from the anode to the cathode, creating the current flow.

Prerequisites for use

Appropriate technology

Electrolysers based on PEM technology (PEM = polymer electrolyte membrane) convert surplus wind and solar power into hydrogen with an efficiency of about 70 per cent, thus ensuring that every kilowatt hour of green electricity can actually be used and that the renewable plants do not have to be shut down if the electricity supply exceeds demand or the grid cannot absorb the power.