THE ROLE OF METHANATION MODELING IN THE SIMULATION OF POWER-TO-GAS SYSTEMS

The role that green hydrogen can play in the future energy systems has been undergoing huge investigations in recent years due to its versatility of use and its exiguous greenhouse impact. However, this energy carrier exhibits low volumetric energy density, difficulties in transportation, and high storage costs. Therefore, if not used at the site of production, it needs to be converted into other carriers for transportation and use. In this framework, synthetic methane can represent a valid option if used as a natural gas substitute taking advantage of its transportation infrastructures. Renewable methane can be synthesized from green hydrogen and captured carbon dioxide in power-to-gas systems. In order to optimize the efficiency of methane production, these systems need to be integrated into larger energy networks where it is possible to benefit from the exploitation of energy in its variety of forms (e.g. electrical, thermal, and chemical). For this reason, the employment of mathematical models is essential for optimal process development. Depending on the purpose of a specific simulation and the time horizon, it is necessary to approach the study with the most suitable level of modeling detail. In this work, the methanation technology is analyzed in the context of power-to-gas on multiple level modeling. Indeed, in several cases, methanation modeling requires the capability to capture characteristics of the input hydrogen such as mass flow rate, moisture content, or pressure. However, in other cases, the focus can regard the whole system operation and control. In such circumstances, the need to analyze specific component characteristics leaves room for considerations of mass and energy transfers, and component operating conditions and efficiencies. The paper at hand proposes and combines two modeling approaches. The choice of a specific approach is suggested considering the obtainment of all the information to be gathered from a specific simulation. The results of the interaction of the methanation reactor with other power-to-gas components are provided.