Linepack Flexibility in Integrated Electricity-Gas Systems: A Comparative Study of Gas Flow Models and Solution Methods

In integrated electricity-gas systems (IEGS), natural gas networks provide flexibility to power systems through linepack—a short-term storage mechanism governed by partial differential equations (PDEs). This study examines how modeling methods (dynamic/DY, steady-state/ST) and solution methods quantify linepack flexibility in mitigating wind power variability. Case studies demonstrate that DY model, which preserve transient flow physics through PDE discretization and pressure-flow coupling, reduce operating costs by 37.5% compared to ST models ignoring dynamics. ​Comparative analysis of solution methods reveals that relaxation-based approaches enhance computational efficiency by simplifying PDE constraints; however, insufficiently tight relaxation bounds introduce substantial physical feasibility deviations, thereby severely overestimating linepack flexibility.