SAM Simulation Core (SSC) Release Notes

The following is a list of changes to SSC variables for programmers using the SAM Software Development Kit (SDK), including the PySAM Python package. If you have a question about these release notes, please post it on the SAM SDK forum.

Additional references:

• SAM release notes
• PySAM release notes

SSC Version 267 (SAM version 2021.12.02, PySAM version 3.0.0)

List of variables whose definition changed in SSC 267

Battery

Refactor the battery dispatch options such that forecast and dispatch algorithm are seperate options. New options for batt_dispatch_choice are:

• Front of meter:
  • 0 - Economic Dispatch
  • 1 - PV Smoothing Dispatch
  • 2 - Custom Dispatch
  • 3 - Manual Dispatch
• Behind the meter:
  • 0 - Automatic Peak Shaving Dispatch
  • 1 - Input Grid Power Target
  • 2 - Custom Dispatch
  • 3 - Manual Dispatch
  • 4 - Price Signals Dispatch

Forecast is now controlled by new variables batt_dispatch_wf_forecast_choice and batt_dispatch_load_forecast_choice:

• 0 - Perfect look ahead
• 1 - One day look behind
• 2 - Custom (using batt_pv_clipping_forecast and batt_pv_ac_forecast for weather and batt_load_ac_forecast and batt_load_ac_forecast_escalation for load

Variables for new behind-the-meter dispatch and power flow calculations:

• batt_dispatch_auto_can_clipcharge: Clip charging for DC connected batteries.
• batt_dispatch_auto_btm_can_discharge_to_grid: Discharging to grid for custom dispatch.
• batt_dispatch_charge_only_system_exceeds_load: For AC connected batteries, 0 means the battery can charge while the grid meets the load. (1 is prior behavior).
• batt_dispatch_discharge_only_load_exceeds_system: For behind-the-meter batteries, 0 means the system discharge the battery while generation is sold to the grid. (1 is prior behavior).
• dispatch_manual_btm_discharge_to_grid: A matrix specifying the schedule of when manual dispatch can discharge to the grid.

Variables for new grid outage calculations:

• grid_outage: Array of timesteps when the grid is unavailable (1) or available (0).
• batt_minimum_outage_SOC: Minimum SOC variable used when grid_outage[t] is 1.
• crit_load_escalation: Array of annual escalation factors for critical load.

New option to enable standalone battery:

• en_standalone_batt: Automatically assigns an array of zeroes to gen.

BatteryStateful

New cycle_counts variable, a 2xn matrix used for rainflow counting when batt_life is set to 0.

UtilityRate5

Front-of-meter financial models (Equpartflip, Levpartflip, Merchantplant, Saleleasback, Singleowner) now use the utility rate module to calculate grid charging and parastics costs.

The following variable names have been changed:

• ur_ec_enable_billing_demand is now ur_enable_billing_demand
• ur_ec_billing_demand_lookback_percentages is now ur_billing_demand_lookback_percentages
• ur_ec_billing_demand_lookback_period is now ur_billing_demand_lookback_period
• ur_ec_billing_demand_minimum is now ur_billing_demand_minimum

The new variable ur_dc_billing_demand_periods specifies the demand charge periods used to calculate billing demand.

List of variables that have been added or removed for SSC 267