Volume 47

Study on power-dividing thermal compensation strategy of wind-electricity-hydrogen storage system Yunbin Han, Zhang Bai, Weiming Shao, Wenjie Hao, Dahai Zhang

Abstract

Wind-powered hydrogen production is a promising method to enhance dispatch flexibility for renewable energy. However, frequent fluctuations of the wind power cause switching of electrolyzer states, resulting in instabilities in the hydrogen production process. Furthermore, the prolonged cold start leads to low operation temperature which thus leads to low energy utilization rate in the wind-powered hydrogen production system. For these concerns, this study proposes a solution for stabilizing the voltage output with variable system temperatures within different power ranges, so as to effectively minimize the frequency of start-stop cycles and enhance the efficiency of hydrogen production. Combined with computational fluid dynamics (CFD), a research model for the polarization characteristic curve of an alkaline electrolyzer (AE) under variable working temperature conditions, as well as a model of wind-powered hydrogen production system considering heat transfer are established. In addition, through non-dominated sorting genetic algorithm, the voltage output schemes, setting efficient and stable hydrogen production in different power intervals as the objective function, are optimized. The proposed strategy is applied to a wind power generation process with a design condition of 1 MW capacity under specific climatic conditions in Northeast China. The system energy efficiency analyses show that, compared with the traditional wind-powered hydrogen production system, the temperature compensation strategy is able to effectively improve the system energy utilization rate by 0.61%. Meanwhile, full-condition operation analyses demonstrate that the system start-stop frequency could be significantly reduced. This study provides a valuable reference program for efficient hydrogen production under variable temperature conditions.

Keywords wind-powered hydrogen production, variable temperature, polarization curve, water electrolysis, power-dividing thermal compensation strategy