Development of a numerical model for PEM electrolysers for the implementation of a simulation-based Digital Twin.

The green hydrogen production through electrolysis is a critical pathway toward achieving carbon neutrality, as it allows for the production of green hydrogen without emissions. Regarding the hydrogen production different aspects of water electrolysers should be analyzed, including efficiency, operating conditions, investment cost, durability, hydrogen purity, infrastructure development and technology maturity. Maintaining optimal operating conditions, such as temperature, pressure and humidity of the stack membranes, can significant enhance the durability and the efficiency of the WE system resulting in less degradation of the components, high-quality hydrogen output and higher cost-effectiveness of hydrogen production. For example in a Proton Exchange Membrane (PEM) water electrolyser, an increase from 60 °C to 80 °C of operating cell temperature at equal conditions (power density: 1 A/cm2), can lead to a reduction up to 75% of the operational time to reduce membrane thickness by 50%. The membrane thickness is strongly correlated with the gas cross over and therefore affects the lifetime of the electrolyser. Moreover, during the electrolyser lifetime, the system is characterized by start-up and shut down cycle phases leading to a reduced lifetime of the stack component due to the introduced thermal stresses. An optimal management of hydrogen productio is therefore considered essential. For instance instead of frequently switching between operational and shutdown phases, a reduction of electrolyser load helps to minimize the system degradation extending its lifespan. The degradation of electrolyser systems significantly influences the cost-efficiency of green hydrogen production. Mitigating the degradation, extends component lifespan, preserves optimal operational performance, and improves the competitiveness of electrolysis technology. Efficient management of electrolyser degradation is essential to ensure the economic feasibility of hydrogen production, especially in large-scale industrial plants. The work is set within the broader context of the development of Hydrogen Valleys, initiatives that aim to create integrated ecosystems where hydrogen is produced, stored, and used. Specifically, the focus is on producing hydrogen using small-scale electrolysers, which are particularly suitable for localized production and flexible deployment. This approach supports the transition toward a decentralized energy system while contributing to the sustainability goals established by the EU commission.