Dynamic simulation of wind-powered alkaline water electrolysis system for hydrogen production

Abstract

Alkaline water electrolysis (AWE) is a mature and cost-effective technology, especially suited for large-scale deployment, yet faces challenges in adapting to the dynamic nature of renewable energy sources. Evaluating AWE's adaptability to fluctuating renewable energy inputs is crucial. This study introduces a dynamic model to assess the influence of wind energy on a 250 kW industrial-scale AWE system for hydrogen production. This paper pioneers the utilization of Aspen Plus Dynamics for dynamic modeling, offering a comprehensive approach that incorporates all vital components and controllers of the balance of plant, such as gas-liquid separator, heat exchangers, deionized water supply, pumps, and the cooling loop. This methodology allows comprehensive simulation at the system level, revealing the real dynamic characteristics of the system under fluctuating wind energy conditions. Due to the absence of a dedicated module for AWE in Aspen Plus Dynamics, an integrated dynamic operation unit for the electrolyzer is constructed using Aspen Custom Modeler. The study analyzes the dynamic characteristics of the AWE system, specifically focusing on temperature, voltage, and liquid level. The study compares two temperature control strategies, before-stack and after-stack, with the refined after-stack method effectively addressing over-temperature issues and improving system energy efficiency by 1.44%.