Holistic and dynamic mathematical model for the assessment of offshore green hydrogen generation and electrolyser design optimisation.

The decarbonisation of the energy system will imply the use of unexplored locations and technologies. In this sense, generation of green H 2 in far-offshore farms may be an alternative. However, the offshore green H 2 generation potential is commonly assessed by using constant conversion rates. This paper presents a holistic and dynamic mathematical model coupling the aero-hydrodynamic model with the polymer electrolyte membrane (PEM) electrolyser model. The model enables a more accurate and comprehensive analysis of the realistic H 2 generation capacity considering the power-to-gas system efficiency. First, the model of the PEM electrolyser is validated and a wide sensitivity analysis is computed in order to report the impact of the operational conditions. Then, H 2 production is assessed focused on (i) the stack performance and (ii) the system performance. The system performance results in a efficiency reduction of up to 10% in the case of FOWTs and up to 70% in WECs due to the fluctuations of the power signal. Hence, results highlight the need for a holistic system assessment instead of focusing on the stack. Finally, transient effects are considered, concluding that in highly fluctuating applications, such as renewables, external heat sources may improve the performance of the system. • A holistic & dynamic model coupling ORE systems with a PEM electrolyser is built. • Stack and System efficiencies are assessed under different operational conditions. • Stack efficiency is shown to be highest at low current densities, i.e. low partial loads. • System efficiency and economical viability are higher close to nominal power. • H 2 generation efficiency is poorer in WECs due to the more significant fluctuations. [ABSTRACT FROM AUTHOR]