Simultaneous optimization of dimensioning and control in green hydrogen production systems based on water electrolysis

Abstract

Green hydrogen, produced by water electrolysis using renewable electricity, is considered a key enabler in the transition toward a net-zero emissions energy and socioeconomic system. In combination with widespread electrification across sectors and the extensive deployment of renewable electricity generation, green hydrogen also plays an important role in decarbonizing hard-to-abate and fossil-dependent industries, while also enabling a scalable solution for the long-term energy storage for renewable electricity. However, the intermittent nature of renewable electricity supply, coupled with the limited dynamic operating capabilities of electrolyzers, introduces significant challenges for the control and dimensioning of hydrogen production systems, ultimately increasing production costs.

This research is motivated by the need to achieve cost-competitive green hydrogen and investigates the optimization of hydrogen production systems from two complementary perspectives, each addressing a distinct scope. The first approach focuses on improving the energy efficiency of industrial-scale water electrolyzer (WE) plants by optimizing the power supply distribution across parallel production lines. An optimization methodology is developed to determine the optimal number of WE lines and their corresponding power supply that maximizes energy efficiency for a given hydrogen production target.

The second optimization scope focuses on the techno-economic analysis for off-grid green hydrogen production systems. A methodology is proposed for the simultaneous optimization of system control and component dimensioning, with the objective of minimizing hydrogen production costs. The optimization results demonstrate and quantify the impact of key techno-economic parameters, including electrolyzer efficiency, start-up time, and simulation time resolution, on system performance and economic feasibility. Additionally, the variability of hydrogen supply is analyzed, revealing that demand-side flexibility significantly reduces hydrogen production costs compared to baseload operation. The findings underscore the importance of integrated, holistic optimization for designing cost-competitive green hydrogen production plants.