Techno-economic comparison of PEM electrolyser operation modes under future electricity prices: A Belgian case study

Proton exchange membrane (PEM) electrolysers are promising technologies for electrolysis due to their fast dynamic response to electricity fluctuations and their lower spatial footprint compared to alternative options. However, the high costs associated with green hydrogen production remain a key challenge for the large-scale deployment of PEM electrolysers within the energy system. This article therefore compares three operational modes of PEM electrolysers: continuous operation at full capacity, price-responsive operation, and combined price- and frequency-responsive operation providing ancillary services. Accordingly, future hourly electricity prices in Belgium, which represents the case study of this article, are estimated based on three potential evolutions of the Belgian energy system and are subsequently applied to the defined operational scenarios. The results show a reduction in the hydrogen break-even price of 11.39–13.10% for the price-adaptive scenario and 18.06–19.38% for the combined price- and frequency-adaptive scenario compared to the full-capacity operation mode across the three electricity price trajectories. Furthermore, a sensitivity analysis is conducted to identify the most influential parameters affecting the hydrogen break-even price, indicating that efficiency is the dominant factor due to the energy-intensive nature of electrolysers. This study provides a globally applicable framework for determining suitable electrolyser operation strategies across a range of power system configurations.