Influence of the Fluctuating Input on Hydrogen Production by Alkaline Water Electrolysis

Water electrolysis by renewable energy is a popular and promising solution for power-to-hydrogen. Conventional water electrolysis prefers DC voltage which needs converters and filters. However, the fluctuation cannot be completely eliminated and the effect of AC power on electrolyzers may not be entirely negative. In this paper, a multi-physics model for hydrogen production by alkaline water electrolysis has been built. Through the latency of bubble accumulation and the convexity of the I-V curve, it is been proved that the fluctuating input may have a positive effect on the hydrogen production. The transient process of the bubble accumulation has been elaborated. An integrated industrial system for hydrogen production by water electrolysis has been built for experiments. From the results, we conclude that dynamic process of the bubble on the electrode will affect the current dynamic process of the electrolyzer. The fluctuating input promotes the hydrogen production rate and reduces the energy conversion efficiency. In the specific case, a 0.7% loss in efficiency can bring 5.3% generation rate, which may be benefit for the industry.