Hydrogen production through grid-connected electrolysers is expected to support the integration of renewable energy, long-duration storage, and the decarbonisation of hard-to-abate sectors. However, large-scale electrolyser deployment introduces new grid integration challenges, particularly as emerging network codes redefine electrolysers as dynamic grid participants rather than passive electrical demand. Conventional grid compliance testing relies on full-stack operation, resulting in continuous hydrogen production, increased operational risk, and high energy consumption during testing.

This study proposes a Power Hardware-in-the-Loop (PHIL) framework for running grid compliance type tests on electrolysers. In this approach, electrolyser stack behaviour is emulated in real time using an aggregated dynamic Electrical Equivalent Circuit (EEC) model. This paper focuses on the development and validation of the real-time-compatible EEC model of an Anion-Exchange Membrane (AEM) electrolyser to reproduce key electrolyser characteristics, including current–voltage behaviour, dynamic electrical response, and hydrogen production rate. The model output was validated against experimental current–voltage data. Furthermore, the flexibility of the modelling framework is demonstrated through its adaptation to represent alternative electrolyser technologies, such as membrane-less electrolysers.

The validated EEC model reproduced the electrolyser's key performance characteristics with sufficient fidelity to replace the physical stack during selected real-time PHIL grid-compliance and converter-interface tests, while preserving electrical behaviour at the converter interface. This reduces reliance on live hydrogen-producing equipment during compliance assessment, improving safety, reducing costs, allowing faster testing, and lowering energy consumption.