2.1.3 Electrolysis
The basic principle of electrolysis is passing the electric current through an electrode couple in order to break water into hydrogen and oxygen molecules\cite{2017}. Today electrolysis is a more expensive method of hydrogen generation in industry than described chemical methods, however it has a great potential as a technology of energy storage (by hydrogen production) from renewable energy sources like wind or solar. The leading techniques of electrolysis include: alkaline electrolysis, proton exchange electrolysis (PEM) and solid oxide electrolysis cells (SOEC). All this three are in detail described in the subsequent chapters. Concerning water splitting for hydrogen production, next to electrolysis there exist methods like thermolysis that utilizes thermal energy and photolysis that utilizes electromagnetic radiation (sun).
2.2 Alkaline electrolysis