Safety and efficiency problems of hydrogen production from alkaline water electrolyzers driven by renewable energy sources

Alkaline water electrolysis has become the most promising solution for hydrogen production considering certain factors such as cost, lifetime and maturity of technology. By developing the large-scale hydrogen production by alkaline water electrolysis as the energy buffering, the consuming pressure of the power system caused by the growing penetration of renewable energy sources such as wind and solar energy can be relieved effectively. However, when the alkaline water electrolysis is integrated with renewable energy sources, the unclear underlying mechanism and interaction characteristics limit large-scale application for hydrogen production. Aiming at this problem, from the aspects of efficiency and consistency, power regulation flexibility and gas purity, this paper studies safety and efficiency problems about the wide-range operation of alkaline water electrolyzers driven by renewable energy sources. The corresponding mechanism analyses are carried out and possible solutions for the future research are given, which are expected to provide a comprehensive review and useful guide for this research topic.