The system-wide WECC simulation runs an hourly day-ahead market across the whole horizon, to 2050. Prices, generation and transmission flows are all set hour by hour.
The model is zonal throughout, with 13 WECC balancing authority nodes. CAISO is modeled as three zones: SCE, SDG&E and PG&E.
Inputs
The table below summarizes the model’s main inputs, how each is built and its key data sources. Each link leads to the full detail.
| Input Type | Input | Summary | Key Data Sets |
|---|---|---|---|
| Generation | Capacity buildout | The capacity expansion model builds new capacity from 2027 on top of today’s fleet and committed queue projects. | EIA-860, WECC ADS, CAISO queue, NREL ATB |
| Generation | Renewable load factors and outages | Renewable availability and outage profiles come from historical data, capturing seasonal and hourly variability. | CPUC SERVM, WECC ADS, NRC |
| Generation | Start costs | Thermal start costs come from historical data and forecast fuel prices. | WECC ADS, EIA-923, EIA AEO |
| Generation | Short-run marginal costs | Short-run marginal costs (SRMCs) are estimated for each plant from historical prices, fuel price forecasts and carbon prices. | WECC ADS, EIA-923, CME, EIA AEO, CEC IEPR |
| Demand | Zonal Demand | Hourly demand by balancing authority follows the CPUC net load forecast to 2050, including EVs, electrification, energy efficiency and behind-the-meter solar. | CPUC SERVM, CAISO OASIS, EIA-930 |
| Transmission | Zonal Transmission Network | Transfer capacities between balancing authorities reflect path ratings and constraints. | CPUC SERVM, WECC ADS, NREL NTP |
Modeling
Two market features are modeled on top of the core inputs: unit commitment and reserve margin. The Dispatch Model page covers single-battery dispatch at the PG&E, SCE and SDG&E nodes.
Unit Commitment
Unit commitment decides whether each generator is on or off in each hour, using binary variables.
Each thermal unit has its own commitment variable. When a unit is online, it must run between its minimum stable output and its maximum output. When offline, its output is zero.
Reserve Margin
Reserve margin is the spare capacity held above expected demand. It protects reliability against generator outages or sudden demand spikes.
The model measures it as headroom across dispatchable thermal and storage assets system-wide. A fixed operating margin is enforced, in line with CAISO’s operating reserve requirements.
Outputs
Macro databook
The Macro Databook summarizes system-level outputs by year. It covers installed capacity by technology, generation, commodity prices, zonal electricity prices and price spreads. Provided as a CSV, it is Modo Energy’s view of capacity expansion, commodity prices and market dynamics.
Site specific databook
The site-specific databook gives monthly and annual metrics for an individual battery, including cycling, merchant revenue and ancillary revenue. Cycles and prices are averaged over each period. Total revenues are also shown per MW, for benchmarking and investment evaluation.