As it was described above, water electrolysis can also be performed using electricity produced from renewable sources.

The most promising source of energy in this area is solar energy. To enhance the efficiency of hydrogen production, new methods of water electrolysis are being developed, such as:

-          high temperature electrolysis (thermolysis)

o   part of the energy is supplied as electrical energy, while the rest is supplied as heat

o   the advantage is an increased process efficiency due to reduced electricity consumption

-          thermochemical cycles

o   water is split into oxygen and hydrogen through a series of chemical reactions, triggered by heat or a combination of heat and electricity in hybrid cycles (the most well-known being the Westinghouse company’s thermochemical cycle – sulfuric acid hybrid cycle).