Understanding the potential impact of renewable penetration, distributed energy resources integration, and demand flexibility on future design and operation of power system is critical for transitions to low-carbon grids. Using the PJM Interconnection as an example, this poster covers two important elements for such energy system modelling: data collection and integration for PJM’s generation fleet, load profiles, transmission constraints, and other elements; the configurable electricity resource capacity expansion model to be used in the study, namely GenX. Such modelling framework for PJM will provide the basis for future transparent and generalized energy system modelling.