Hydrogen from water electrolysis

Hydrogen production via electrolysis of water (water splitting reaction) is a means of storing excess electrical energy produced by renewable energy sources. This hydrogen gas may be used directly to produce power via combustion or recombination with oxygen in a fuel cell; it may be injected into the natural gas network; and it may be used as a transport fuel or as a chemical intermediate. The main methods of hydrogen production via electrolysis are described: alkaline, proton exchange membrane, and solid-oxide. The materials of construction and the advantages and disadvantages of each system are considered. Methods of storing the hydrogen produced via electrolysis are presented along with the integration of production and storage into large-scale demonstration projects. Finally, selected emerging technologies are considered with respect to how they address shortcomings with the current technology.