This study investigates the behavior of the German transmission gas network infrastructure with and without green hydrogen injection. Based on the simulation results of different scenarios, the challenges and criticality that arise with hydrogen blending are evaluated and analysed in detail. One of the main aims of this study is to simulate and evaluate the gas network steady-state simulation using open-source-only datasets and tools. To achieve this, the natural gas consumption data of Germany is first studied. After comparing two different open-source datasets, the dataset DemandRegio is chosen, which provides hourly data for gas consumption in Germany with a NUTS-3 spatial resolution.