2.7 Static Model
The dynamic version of US-REGEN can run in concert with the end-use model over multi-decadal time steps and, as outlined in Section 2.5, uses a reduced set of representative hours to reflect load, wind, and solar profiles. To enable full 8760 hourly resolution, US-REGEN can also be run in static mode. This annual version of the model abandons intertemporal optimization in favor of a detailed hourly representation of an annual slice of electric sector operation. Instead of using aggregated representative hours, the static model computes dispatch for each of the full 8,760 hours. In other respects, the operation of the model remains similar. Generation units remain aggregated into capacity blocks that are dispatched together, and the capacity mix is determined endogenously based on a rental formulation for new capacity. Fuel prices and energy demand are fixed, and the model linearly optimizes to balance the load.
The static model is a useful bridge between the sub-hourly timescales that detail the daily operations of the power system and the long-run projections of the sort that US-REGEN's coupled electricity and end-use models generate. The complete hourly generation profile created by the static model helps evaluate the efficacy of the long-run dynamic model by noting the differences between complete hourly generation and demand profiles with the aggregated representative hours methodology of the dynamic model. Because of the rental formulation, there are no retirement decisions. The static model can be started from any given base year reading off the data from a dynamic model run. This allows the static model to test the hour-to-hour response of a projected system state output by the dynamic model, giving a more realistic assessment of the hourly load shape and generation choices for a given future state. In turn, the dynamic model informs the static model's profile of generation assets and outputs a fixed demand, assessing how the intra-yearly challenges affect the shifting equilibrium of generation and end-use demand.
One major advantage of the static model is the ability to consider storage challenges. The hourly model naturally maintains chronology, which allows the model to accurately represent the generation and storage of electricity across adjacent hourly load segments.
The static version of US-REGEN can also be configured to include the supply, transmission, and storage of natural gas. Supply is modeled at the basin level and differentiated by reservoir type. Demand for gas in the power sector is modeled at an hourly level linked to dispatch in the electric model. Demand for gas in the end-use sectors is based on a scenario from the end-use model (see Chapter 3). State-level pipeline and storage facility data is aggregated to the regional level and constrains the movement of gas between supply and demand with daily resolution. The inclusion of this additional structure of the gas market leads to regional and seasonal variation in the natural gas price.