This thesis investigates how operational strategies influence the performance of offshore PEM electrolyser systems powered by intermittent offshore wind power. The central research question is:

“How does the operational strategy for managing intermittent offshore wind power supply in an
offshore PEM electrolyser system affect hydrogen production, stack degradation and the LCOH?”

The study follows three phases. A literature review establishes PEM electrolysis as the most suitable technology for offshore hydrogen production, identifies degradation mechanisms under intermittent power operation, and derives a degradation relation. A dynamic Simulink model is then developed to simulate stack performance under variable power inputs. Finally, a techno-economic model in Python integrates the Simulink results with degradation data to evaluate operational strategies.

The analysis compares three strategies: equal-, serial-, and optimal efficiency power distribution over the stacks. Results show that operational strategy is a decisive factor. Equal distribution achieves the lowest LCOH of 12.17 $/kg with 68 stack replacements over a 15 year horizon, while serial distribution results in a 30% higher LCOH of 15.83 $/kg and requires 90 replacements. Hydrogen output differences between strategies are minimal. Strategy performance is best when operation under high current density is avoided, as this is a driving factor for degradation. The LCOH values remain significantly higher than those of fossil fuel based hydrogen.

The findings of this thesis also expose a critical knowledge gap: PEM electrolyser degradation under intermittent operation is poorly understood. Testing protocols are inconsistent, datasets fragmented, and long-term field data scarce. This complicates the viability assessment of future offshore hydrogen projects.

This research contributes by (1) highlighting the urgent need for standardized degradation testing and long-term datasets, (2) introducing a simulation framework that combines time-resolved dynamic modelling with techno-economic analysis, and (3) establishing operational strategy as a critical design factor for offshore hydrogen systems.

Future research should focus on (i) long-term degradation testing under realistic renewable power profiles, (ii) advanced time-resolved modelling with higher time resolution and incorporation of transient effects, (iii) development of optimization-based operational strategies, and (iv) integrated techno-economic analysis that includes dynamic electricity prices, offshore infrastructure, and possible integration of batteries.

To answer the research question: the operational strategy for managing intermittent offshore wind power supply has a significant impact on the performance of offshore PEM electrolyser systems, as strategies that avoid high current density operation substantially reduce degradation and lower the LCOH by up to 30%, while having only a limited effect on hydrogen production.