Tools

These helper functions provide additional functionality for working with specific models.

Resource Tools

These can be accessed via import PySAM.ResourceTools

These functions help with solar resource, wind resource and utility rate data, downloads and formatting. See how to download solar resource data from the National Solar Radiation Database or wind resource data from the WindToolKit. Use resource files directly in your PySAM models or input them as dictionaries.

Please see an example of FetchResource here

class files.ResourceTools.FetchResourceFiles(tech, nrel_api_key, nrel_api_email, workers=1, resource_type='psm3-tmy', resource_year='tmy', resource_interval_min=60, resource_height=100, resource_dir=None)

Download solar and wind resource files from NREL developer network https://developer.nrel.gov/.

Parameters:tech (str) – Required Name of technology. ‘wind’ for NREL WIND Toolkit at https://developer.nrel.gov/docs/wind/wind-toolkit/wtk-download/. ‘solar’ for NREL NSRDB at https://developer.nrel.gov/docs/solar/nsrdb/nsrdb_data_query/

!param str nrel_api_key: Required NREL developer API key, available at https://developer.nrel.gov/signup/.

Parameters:
  • nrel_api_email (str) – Required Email address associated with nrel_api_key.
  • resource_dir (str) – Directory to store downloaded files. Default = ‘None’, which results in data/PySAM Downloaded Weather Files.
  • workers (int) – Number of threads to use when parellelizing downloads. Default = 1.
  • resource_type (str) – Name of API for NSRDB solar data. Default = ‘psm3-tmy’ for solar, ‘’ for wind. ‘psm3’ for 30- or 60-minute single-year file ‘psm3-tmy’ for 60-minute TMY, TGY, or TDY typical-year file ‘psm3-5min’ for 5-, 30- or 60-minute single-year file ‘’ for WIND Toolkit
  • resource_year (str) – Data year, changes over time so check API documentation for latest information. Default = ‘tmy’ for solar, ‘2014’ for wind. ‘1998’ to ‘2019’, etc. for NSRDB psm3 ‘tmy’ for latest TMY file from NSRDB psm3-tmy ‘tmy-2016’ to ‘tmy-2018’, etc. for NSRDB psm3-tmy ‘2018’, etc. for NSRDB psm3-5min ‘2007’ to ‘2014’ for WIND Toolkit
  • resource_interval_min (int) – Time interval of resource data in minutes. See available intervals under resource_type above. Default = 60.
  • resource_height (int) – For wind only, wind resource measurement height above ground in meters. Default = 100. 10, 40, 60, 80, 100, 120, 140, 160 for windspeed, winddirection, temperature 0, 100, 200 for pressure
fetch(points)

Creates dict with {region:path_to_SAM_resource_file}.

Parameters:points (iterable) – Iterable of lon/lat tuples, i.e. Shapely Points.
files.ResourceTools.SAM_CSV_to_solar_data(filename)

Format a TMY csv file as ‘solar_resource_data’ dictionary for use in PySAM. For more information about SAM CSV file format, see https://sam.nrel.gov/weather-data/weather-data-publications.html

Parameters:filename – Any csv resource file formatted according to NSRDB
Returns:Dictionary for PySAM.Pvwattsv7.Pvwattsv7.SolarResource, and other models
files.ResourceTools.SRW_to_wind_data(filename)

Format as ‘wind_resource_data’ dictionary for use in PySAM. For more information about SRW file format, see https://sam.nrel.gov/weather-data/weather-data-publications.html

Parameters:filename – A .srw wind resource file
Returns:Dictionary for PySAM.Windpower.Windpower.Resource
files.ResourceTools.URDBv7_to_ElectricityRates(urdb_response)
Formats response from Utility Rate Database API version 7 for use in PySAM
i.e.
model = PySAM.UtilityRate5.new() rates = PySAM.ResourceTools.URDBv7_to_ElectricityRates(urdb_response) model.ElectricityRates.assign(rates)
Param:urdb_response: dictionary with response fields following https://openei.org/services/doc/rest/util_rates/?version=7
Returns:dictionary for PySAM.UtilityRate5.UtilityRate5.ElectricityRates

Battery Tools

These can be accessed via import PySAM.BatteryTools

files.BatteryTools.battery_model_change_chemistry(model, chem)

Changes the chemistry and cell properties of the battery to use defaults for that chemistry from BatteryStateful

Parameters:
  • model – PySAM.Battery.Battery or PySAM.BatteryStateful.BatteryStateful
  • chem – string ‘leadacid’, ‘lfpgraphite’, ‘nmcgraphite’, ‘lmolto’
files.BatteryTools.battery_model_sizing(model, desired_power, desired_capacity, desired_voltage, size_by_ac_not_dc=None, module_specs: dict = None)

Sizes the battery model using its current configuration such as chemistry, cell properties, etc and modifies the model’s power, capacity and voltage without changing its fundamental properties

The battery’s thermal parameters (surface area and mass) are modified according to assumptions about the mass and volume per specific energy and assuming the battery is a cube. If the battery’s thermal parameters should be sized according to a particular module’s capacity and surface area, use the module_specs input.

Parameters:
  • model – PySAM.Battery.Battery or PySAM.BatteryStateful.BatteryStateful
  • desired_power – float Battery: kWAC if AC-connected, kWDC otherwise BatteryStateful: battery kWDC
  • desired_capacity – float Battery: kWhAC if AC-connected, kWhDC otherwise BatteryStateful: battery kWhDC
  • desired_voltage – float volts
  • size_by_ac_not_dc – optional bool Sizes for power and capacity are on AC side not DC side of battery-inverter regardless of connection type
  • module_specs –

    optional dict Module specifications for scaling surface area assuming the battery is made of inividual modules.

    capacity: float
    Single battery module capacity for scaling surface area Battery: kWhAC if AC-connected, kWhDC otherwise BatteryStateful: battery kWhDC
    surface_area: float
    Single battery module surface area m^2 m^2 of module battery
files.BatteryTools.calculate_battery_size(input_dict)

Helper function to battery_model_sizing

All efficiencies and rates in percentages, 0-100.

Inverter efficiency depends on which inverter model is being used, inverter_model.

Parameters:input_dict –
batt_chem: int
Lithium-ion (1) or Lead-Acid (0)
batt_Qfull: float, Ah
capacity of single cell
batt_Vnom_default: float, V
voltage of single cell
Required only if batt_chem is False:
LeadAcid_q10: float 0-100, Ah
10 hour discharge rate
LeadAcid_q20: float 0-100, Ah
20 hour discharge rate
LeadAcid_tn: int, hour
hour for custom hour discharge rate
LeadAcid_qn: float 0-100, Ah
n-hour discharge rate
batt_ac_or_dc: bool
True if ac-connected
desired_power: float, kW
power of the battery
desired_capacity: float, kWh
capacity
desired_voltage: float, V
voltage
size_by_ac_not_dc: bool, default False
True for sizing battery as kWAC and kWhAC
batt_dc_ac_efficiency: float 0-100, required only if size_by_ac_not_dc is True
AC to DC power in conversion
inverter_eff: float 0-100, required only if batt_ac_or_dc is False
AC to DC power from inverter
batt_dc_dc_efficiency: float 0-100, optional
DC to DC power conversion in battery management system
Returns:output_dict: voltage: float, V
computed
power: float
computed
batt_computed_bank_capacity: float
computed
batt_computed_series: int
number of cells connected in series
batt_computed_strings: int
number of strings connected in parallel

time_capacity: float 0-1

batt_current_charge_max: float, A

batt_current_discharge_max: float, A

batt_power_charge_max_kwac: float, kWAC

batt_power_discharge_max_kwac: float, kWAC

batt_power_charge_max_kwdc: float, kWDC

batt_power_discharge_max_kwdc: float, kWDC

only if batt_chem is False:
LeadAcid_q10_computed: float 0-100, Ah

LeadAcid_q20_computed: float 0-100, Ah

LeadAcid_qn_computed: float 0-100, Ah
files.BatteryTools.calculate_thermal_params(input_dict)

Calculates the mass and surface area of a battery by calculating from its current parameters the mass / specific energy and volume / specific energy ratios.

If module_capacity and module_surface_area are provided, battery surface area is calculated by scaling module_surface_area by the number of modules required to fulfill desired capacity.

Param:
input_dict:
mass: float

kg of battery at original size

surface_area: float

m^2 of battery at original size

original_capacity: float

Wh of battery

desired_capacity: float

Wh of new battery size

module_capacity: optional float

Wh of module battery size

module_surface_area: optional float

m^2 of module battery
Returns:

mass: float

kg of battery at desired size

surface_area: float

m^2 of battery at desired size
Return type:

output_dict
files.BatteryTools.chem_battery(model: Union[Battery, Pvsamv1], chem)

Helper function for battery_model_change_chemistry

files.BatteryTools.chem_batterystateful(model: BatteryStateful, chem)

Helper function for battery_model_change_chemistry

files.BatteryTools.size_battery(model, desired_power, desired_capacity, desired_voltage, size_by_ac_not_dc=None, module_dict=None)

Helper function for battery_model_sizing Modifies Battery model with new sizing. For BatteryStateful use size_batterystateful

Parameters:
  • model – PySAM.Battery model
  • desired_power – float kWAC if AC-connected, kWDC otherwise
  • desired_capacity – float kWhAC if AC-connected, kWhDC otherwise
  • desired_voltage – float volts
  • size_by_ac_not_dc – optional bool Sizes for power and capacity are on AC side not DC side of battery-inverter
  • module_dict –

    optional dict Module specs for scaling surface area

    capacity: float
    Single battery module capacity for scaling surface area kWhAC if AC-connected, kWhDC otherwise
    surface_area: float
    Single battery module surface area m^2 m^2 of module battery
Returns:

output_dictionary of sizing parameters
files.BatteryTools.size_batterystateful(model: BatteryStateful, _, desired_capacity, desired_voltage, module_dict=None)

Helper function for battery_model_sizing

Modifies BatteryStateful model with new sizing. For Battery use size_battery

Only battery side DC sizing

Parameters:
  • model – PySAM.Battery model
  • _ – not used
  • desired_capacity – float kWhAC if AC-connected, kWhDC otherwise
  • desired_voltage – float volts
  • module_dict –

    optional dict Module specs for scaling surface area

    capacity: float
    Single battery module capacity for scaling surface area kWhAC if AC-connected, kWhDC otherwise
    surface_area: float
    Single battery module surface area m^2 m^2 of module battery
Returns:

output_dictionary of sizing parameters