*4.1. Authenticity Test*

The validity of a model should be confirmed after the formulation of the model's structure and data collection. It is very critical to ensure that the model dynamically captures the relationships among the variables and that the model fits real-world conditions. First, since the variables were specified using open and reliable data sources and expert opinions, the equations were meaningful. A unit check using Vensim software was successful, and thus the model was deemed to be suitable and reasonable. We assumed two extreme scenarios and chose two representative variables to demonstrate if the coupled markets' actions were compatible with reality. Figure 3 displays the results when the systems are free from risks and when both the natural gas and the electricity markets collapse. We can see that in the absence of any risks, the markets' supply can meet demand at a good rate, and the emergency supply is not activated, keeping the natural gas reserve capacity constant. However, when both markets fail, we can see a rapid drop in the system's overall satisfaction rate. Additional natural gas will then be provided, depleting the natural gas reserves. The natural gas reserves are exhausted on day 126, and the system continues to collapse. The authenticity test results demonstrated that the model was both effective and valid.
