Integral Characteristics of Hydrogen Production in Alkaline Electrolysers

Abstract

This paper summarises the results of experimental investigations of a commercial alkaline water electrolyser used for hydrogen production to balance decentralised electricity production from renewables. Experiments have been conducted on an alkaline water electrolyser operating at a pressure range up to 25 bar g and having a maximum production capacity of 15 Nm³ hydrogen per hour. In stationary conditions, the energy efficiency of an electrolytic cell has been calculated, and the characteristics of the electrolyser stack has been described with an empirical equation. The energy efficiency of the entire system and hydrogen losses within the boundaries of the system have been determined. Experimental results show that the energy efficiency of an electrolytic cell at typical operating conditions ranges between 73 and 83%, and the energy efficiency of the entire system is between 50 and 60%. Hydrogen losses within the boundaries of the system, compared to the total produced amount of hydrogen, are between 10 and 25%, depending of operating conditions.

H2 generation from alkaline electrolyzer

“…Conventional AWEs typically reach energy efficiencies of 73 – 83% . The costs of hydrogen produced in Germany in 2012 either with an alkaline or a PEM electrolyzer from mainstream grid power supply in comparison to hydrogen from a balancing scenario, using excessive energy to operate the electrolyzer or a renewable generator within an off‐grid scenario are listed in Table .…”

Photocatalytic Water Oxidation on ZnO: A Review

“…The energy consumption of industrial-scale electrolyzers is high due to the energy barriers imposed by cathodic and anodic overpotentials, as well as IR drop between electrodes [8]. Coupling renewable energy sources with electrolyzers has been proposed to be a sustainable approach to utilize excess renewable energy produced at low-demand times of the day.…”

Electrolyzers Enhancing Flexibility in Electric Grids

“…Compression and transportation at higher pressures and lower temperatures of hydrogen are the main reasons for high cost within hydrogen delivery systems [17]; hence distributed rather than centralized hydrogen production is favored [18]. Electrolyzers are one of the techniques used to produce hydrogen and can also be optimized by co-location to enhance integration with renewable resources [19,20]. There are two main types of low-temperature electrolyzers, namely, alkaline technology that uses liquid electrolyte and proton exchange membrane (PEM), which replaces the liquid electrolyte with a solid polymer electrolyte.…”