Simulations of Hydrogen Blending in Gas Grids: Development of a Dynamic Framework for Multi-Node Injection

Hydrogen is a driving force in the transition to a sustainable energy system, particularly in industry and transport sectors. As the number of electrolysers increases, the existing infrastructure is not sufficient to distribute the growing volume of hydrogen. Blending hydrogen into the natural gas grid offers a practical transitional solution. To fully assess the potential of blending in relation to the system integration of hydrogen, detailed modelling is required. However, most existing studies rely on steady-state models or focus on single injection points, limiting their ability to capture the dynamic behaviour of real networks. This thesis presents a simulation framework for time-dependent hydrogen injection at multiple nodes in a gas network. The framework is based on a modular, component-oriented approach allowing flexible network design and scenario analysis. A central aim is to compare the performance of steady-state and dynamic simulations in representing hydrogen distribution
across the grid. In addition, the approach is used to investigate how injection rates can be
improved by optimising injection locations. The results show that steady-state models often
misrepresent hydrogen concentrations by ignoring temporal and spatial variations. This can lead to under- or overestimation of injection potentials and misjudgment of safety thresholds.
In contrast, the dynamic model provides a more accurate picture of the system behaviour.
Moreover, the findings demonstrate that injection rates can be significantly improved by
selecting appropriate injection points.