Influence of renewable energy power fluctuations on water electrolysis for green hydrogen production

TLDR

Renewable energy technologies are essential for carbon neutrality, and hydrogen offers large‑scale storage, but green hydrogen production requires a detailed understanding of water electrolysis under intermittent fluctuating power, which differs markedly from steady‑grid operation and presents several challenges. The article reviews fluctuating power characteristics, generation, and the status and issues of operation conditions, electrolyzer configuration, system requirements, stack/catalyst durability, and degradation mechanisms when directly using fluctuating power. The authors present an accelerated degradation test protocol to fairly compare catalyst performance and guide effective design directions for electrolyzers under fluctuating power. The review highlights challenges and offers recommendations for improving electrolyzer components and systems, indicating that breakthroughs could enable a sustainable hydrogen‑based society.

Abstract

The development of renewable energy technologies is essential to achieve carbon neutrality. Hydrogen can be stably stored and transported in large quantities to maximize power utilization. Detailed understanding of the characteristics and operating methods of water electrolysis technologies, in which naturally intermittent fluctuating power is used directly, is required for green hydrogen production, because fluctuating power-driven water electrolysis processes significantly differ from industrial water electrolysis processes driven by steady grid power. Thus, it is necessary to overcome several issues related to the direct use of fluctuating power. This article reviews the characteristics of fluctuating power and its generation as well as the current status and issues related to the operation conditions, water electrolyzer configuration, system requirements, stack/catalyst durability, and degradation mechanisms under the direct use of fluctuating power sources. It also provides an accelerated degradation test protocol method for fair catalyst performance comparison and share of effective design directions. Finally, it discusses potential challenges and recommendations for further improvements in water electrolyzer components and systems suitable for practical use, suggesting that a breakthrough could be realized toward the achievement of a sustainable hydrogen-based society.