Include Nominal Discount Rate in output

Author: softwareengineerprogrammer

src/geophires_x/Economics.py

@@ -5,7 +5,7 @@
 import geophires_x.Model as Model
 from geophires_x import EconomicsSam
 from geophires_x.EconomicsSam import calculate_sam_economics, SamEconomicsCalculations
-from geophires_x.EconomicsUtils import BuildPricingModel, wacc_output_parameter
+from geophires_x.EconomicsUtils import BuildPricingModel, wacc_output_parameter, nominal_discount_rate_parameter
 from geophires_x.OptionList import Configuration, WellDrillingCostCorrelation, EconomicModel, EndUseOptions, PlantType, \
     _WellDrillingCostCorrelationCitation
 from geophires_x.Parameter import intParameter, floatParameter, OutputParameter, ReadParameter, boolParameter, \
@@ -1775,6 +1775,9 @@ def __init__(self, model: Model):
             CurrentUnits=PercentUnit.PERCENT
         )
 
+        self.nominal_discount_rate = self.OutputParameterDict[self.nominal_discount_rate.Name] = (
+            nominal_discount_rate_parameter())
+
         self.wacc = self.OutputParameterDict[self.wacc.Name] = wacc_output_parameter()
 
         # TODO this is displayed as "Project Net Revenue" in Revenue & Cashflow Profile which is probably not an
@@ -2758,6 +2761,8 @@ def Calculate(self, model: Model) -> None:
         non_calculated_output_placeholder_val = -1
         if self.econmodel.value == EconomicModel.SAM_SINGLE_OWNER_PPA:
             self.sam_economics_calculations = calculate_sam_economics(model)
+            self.wacc.value = self.sam_economics_calculations.wacc.value
+            self.nominal_discount_rate.value = self.sam_economics_calculations.nominal_discount_rate.value
             self.ProjectNPV.value = self.sam_economics_calculations.project_npv.quantity().to(
                 convertible_unit(self.ProjectNPV.CurrentUnits)).magnitude
             self.ProjectIRR.value = self.sam_economics_calculations.project_irr.quantity().to(

src/geophires_x/EconomicsSam.py

@@ -27,7 +27,7 @@
 
 from geophires_x import Model as Model
 from geophires_x.EconomicsSamCashFlow import _calculate_sam_economics_cash_flow
-from geophires_x.EconomicsUtils import BuildPricingModel, wacc_output_parameter
+from geophires_x.EconomicsUtils import BuildPricingModel, wacc_output_parameter, nominal_discount_rate_parameter
 from geophires_x.GeoPHIRESUtils import is_float, is_int
 from geophires_x.OptionList import EconomicModel, EndUseOptions
 from geophires_x.Parameter import Parameter, OutputParameter, floatParameter
@@ -63,6 +63,8 @@ class SamEconomicsCalculations:
         )
     )
 
+    nominal_discount_rate: OutputParameter = field(default_factory=nominal_discount_rate_parameter)
+
     wacc: OutputParameter = field(default_factory=wacc_output_parameter)
 
 
@@ -159,27 +161,32 @@ def sf(_v: float) -> float:
     sam_economics.project_npv.value = sf(single_owner.Outputs.project_return_aftertax_npv * 1e-6)
     sam_economics.capex.value = single_owner.Outputs.adjusted_installed_cost * 1e-6
 
-    sam_economics.wacc.value = _calculate_wacc(model, single_owner)
+    sam_economics.nominal_discount_rate.value, sam_economics.wacc.value = _calculate_nominal_discount_rate_and_wacc(
+        model, single_owner
+    )
 
     return sam_economics
 
 
-def _calculate_wacc(model: Model, single_owner: Singleowner) -> float:
+def _calculate_nominal_discount_rate_and_wacc(model: Model, single_owner: Singleowner) -> tuple[float]:
     """
     Calculation per SAM Help -> Financial Parameters -> Commercial -> Commercial Loan Parameters -> WACC
+
+    :return: tuple of Nominal Discount Rate (%), WACC (%)
     """
 
     econ = model.economics
-    nominal_discount_rate = ((1 + econ.discountrate.value) * (1 + econ.RINFL.value) - 1) * 100
+    nominal_discount_rate_pct = ((1 + econ.discountrate.value) * (1 + econ.RINFL.value) - 1) * 100
     fed_tax_rate = max(single_owner.Outputs.cf_federal_tax_frac)
     state_tax_rate = max(single_owner.Outputs.cf_state_tax_frac)
     effective_tax_rate = (fed_tax_rate * (1 - state_tax_rate) + state_tax_rate) * 100
     debt_fraction = single_owner.Outputs.debt_fraction / 100
-    wacc = (
-        nominal_discount_rate / 100 * (1 - debt_fraction)
+    wacc_pct = (
+        nominal_discount_rate_pct / 100 * (1 - debt_fraction)
         + debt_fraction * econ.BIR.value * (1 - effective_tax_rate / 100)
     ) * 100
-    return wacc
+
+    return nominal_discount_rate_pct, wacc_pct
 
 
 def get_sam_cash_flow_profile_tabulated_output(model: Model, **tabulate_kw_args) -> str:

src/geophires_x/EconomicsUtils.py

@@ -52,3 +52,16 @@ def wacc_output_parameter() -> OutputParameter:
         CurrentUnits=PercentUnit.PERCENT,
         PreferredUnits=PercentUnit.PERCENT,
     )
+
+
+def nominal_discount_rate_parameter() -> OutputParameter:
+    return OutputParameter(
+            Name="Nominal Discount Rate",
+            ToolTipText="Nominal Discount Rate is displayed for SAM Economic Models. "
+                        "It is calculated according to the following formula, defined in SAM Help documentation: "
+                        "Nominal Discount Rate = [ ( 1 + Real Discount Rate ÷ 100 ) "
+                        "× ( 1 + Inflation Rate ÷ 100 ) - 1 ] × 100.",
+            UnitType=Units.PERCENT,
+            CurrentUnits=PercentUnit.PERCENT,
+            PreferredUnits=PercentUnit.PERCENT,
+        )

src/geophires_x/Outputs.py

@@ -252,14 +252,25 @@ def PrintOutputs(self, model: Model):
                     f.write(f'      Economic Model = {model.economics.econmodel.value.value}\n')
 
                 if model.economics.econmodel.value == EconomicModel.SAM_SINGLE_OWNER_PPA:
-                    # TODO disambiguate interest rate for all economic models - see
-                    #  https://github.com/softwareengineerprogrammer/GEOPHIRES/commit/535c02d4adbeeeca553b61e9b996fccf00016529
-                    ir_fl = Outputs._field_label(econ.interest_rate.Name, 49)
-                    f.write(f'      {ir_fl}{econ.interest_rate.value:10.2f} {econ.interest_rate.CurrentUnits.value}\n')
-
-                    wacc = econ.sam_economics_calculations.wacc
-                    wacc_fl = Outputs._field_label(wacc.Name, 49)
-                    f.write(f'      {wacc_fl}{wacc.value:10.2f} {wacc.CurrentUnits.value}\n')
+                    fields : list[OutputParameter] = [
+                        # TODO disambiguate interest rate for all economic models - see
+                        #  https://github.com/softwareengineerprogrammer/GEOPHIRES/commit/535c02d4adbeeeca553b61e9b996fccf00016529
+                        econ.interest_rate,
+
+                        econ.nominal_discount_rate,
+                        econ.wacc,
+                    ]
+
+                    for field in fields:
+                        label = Outputs._field_label(field.Name, 49)
+                        f.write(f'      {label}{field.value:10.2f} {field.CurrentUnits.value}\n')
+
+                    # ir_fl = Outputs._field_label(econ.interest_rate.Name, 49)
+                    # f.write(f'      {ir_fl}{econ.interest_rate.value:10.2f} {econ.interest_rate.CurrentUnits.value}\n')
+                    #
+                    # wacc = econ.sam_economics_calculations.wacc
+                    # wacc_fl = Outputs._field_label(wacc.Name, 49)
+                    # f.write(f'      {wacc_fl}{wacc.value:10.2f} {wacc.CurrentUnits.value}\n')
 
                 # FIXME TODO unit is missing https://github.com/NREL/GEOPHIRES-X/issues/382
                 f.write(f'      Accrued financing during construction:            {model.economics.inflrateconstruction.value*100:10.2f} {model.economics.inflrateconstruction.CurrentUnits.value}\n')

src/geophires_x_client/geophires_x_result.py

@@ -68,6 +68,7 @@ class GeophiresXResult:
                 _EqualSignDelimitedField('Economic Model'),
                 'Interest Rate',  # %
                 'WACC',
+                'Nominal Discount Rate',
                 'Accrued financing during construction',
                 'Project lifetime',
                 'Capacity factor',

src/geophires_x_schema_generator/geophires-result.json

@@ -79,6 +79,11 @@
           "description": "Weighted Average Cost of Capital displayed for SAM Economic Models. It is calculated according to the following formula, defined in SAM Help documentation: WACC = [ Nominal Discount Rate \u00f7 100 \u00d7 (1 - Debt Percent \u00f7 100) + Debt Percent \u00f7 100 \u00d7 Loan Rate \u00f7 100 \u00d7  (1 - Effective Tax Rate \u00f7 100 ) ] \u00d7 100; Effective Tax Rate = [ Federal Tax Rate \u00f7 100 \u00d7 ( 1 - State Tax Rate \u00f7 100 ) + State Tax Rate \u00f7 100 ] \u00d7 100; Nominal Discount Rate = [ ( 1 + Real Discount Rate \u00f7 100 ) \u00d7 ( 1 + Inflation Rate \u00f7 100 ) - 1 ] \u00d7 100. ",
           "units": "%"
         },
+        "Nominal Discount Rate": {
+          "type": "number",
+          "description": "Nominal Discount Rate is displayed for SAM Economic Models. It is calculated according to the following formula, defined in SAM Help documentation: Nominal Discount Rate = [ ( 1 + Real Discount Rate \u00f7 100 ) \u00d7 ( 1 + Inflation Rate \u00f7 100 ) - 1 ] \u00d7 100.",
+          "units": "%"
+        },
         "Accrued financing during construction": {},
         "Project lifetime": {},
         "Capacity factor": {},

tests/examples/example_SAM-single-owner-PPA.out

@@ -6,8 +6,8 @@ Simulation Metadata
 ----------------------
  GEOPHIRES Version: 3.9.6
  Simulation Date: 2025-05-14
- Simulation Time:  10:30
- Calculation Time:      0.883 sec
+ Simulation Time:  11:19
+ Calculation Time:      0.880 sec
 
                            ***SUMMARY OF RESULTS***
 
@@ -26,6 +26,7 @@ Simulation Metadata
       Economic Model = SAM Single Owner PPA
       Interest Rate:                                         7.00 %
       WACC:                                                  6.41 %
+      Nominal Discount Rate:                                 9.14 %
       Accrued financing during construction:                  5.00
       Project lifetime:                                      20 yr
       Capacity factor:                                       90.0 %