WIP - adjusting S-DAC parameterization based on further research

Author: softwareengineerprogrammer

.gitignore

@@ -125,6 +125,7 @@ src/geophires_docs/fervo_project_red-2026_graph-data-extraction.xcf
 /Useful sites for Sphinx docstrings.txt
 /.github/workflows/workflows.7z
 tmp.patch
+project-structure.txt
 
 # Mypy Cache
 .mypy_cache/

src/geophires_x/EconomicsS_DAC_GT.py

@@ -219,7 +219,7 @@ def __init__(self, model: Model):
             ErrMessage="assume default Percent Energy Devoted To Process (50%)",
             ToolTipText="Percent Energy Devoted To Process (%)"
         )
-        self.carbon_credit_price = floatParameter(
+        self.carbon_credit_price = self.ParameterDict[self.carbon_credit_price.Name] = floatParameter(
             "S-DAC-GT Carbon Credit Price",
             value=180.0,
             DefaultValue=180.0,
@@ -231,7 +231,19 @@ def __init__(self, model: Model):
             ErrMessage="assume default Carbon Credit Price (180 USD per tonne CO2)",
             ToolTipText="Carbon Credit or Market Price (USD per tonne CO2)"
         )
-        self.ParameterDict[self.carbon_credit_price.Name] = self.carbon_credit_price
+
+        self.carbon_credit_duration = self.ParameterDict[self.carbon_credit_duration.Name] = floatParameter(
+            "S-DAC-GT Carbon Credit Duration",
+            value=12.0,
+            DefaultValue=12.0,
+            Min=0.0,
+            Max=100.0,
+            UnitType=Units.TIME,
+            PreferredUnits=TimeUnit.YEAR,
+            CurrentUnits=TimeUnit.YEAR,
+            ErrMessage="assume default Carbon Credit Duration (12 years)",
+            ToolTipText="Duration for which the carbon credit can be claimed (e.g., 12 years for US 45Q)"
+        )
 
         # local variable initiation
         # Capital Recovery Rate or Fixed Charge Factor - set initially for definitions
@@ -511,6 +523,13 @@ def range_check(self) -> tuple:
                                                                                                   storage_max)
             return True, error_message
 
+        if not (self.carbon_credit_duration.Min
+                <= self.carbon_credit_duration.value
+                <= self.carbon_credit_duration.Max):
+            error_message = "S-DAC-GT ERROR: Carbon Credit Duration should be between {} and {}".format(
+                self.carbon_credit_duration.Min, self.carbon_credit_duration.Max)
+            return True, error_message
+
         return False, ""
 
     def geo_therm_cost(self, power_cost: float, CAPEX_mult: float, OPEX_mult: float, depth: float,
@@ -703,16 +722,19 @@ def Calculate(self, model: Model) -> None:
                                                                (self.CarbonExtractedAnnually.value[
                                                                     i] * self.therm.value))
 
-        # Calculate Carbon Revenue based on S-DAC-GT specific credit price
+        # Calculate Carbon Revenue based on S-DAC-GT specific credit price and duration
         self.CarbonRevenue.value = [0.0] * model.surfaceplant.plant_lifetime.value
         self.CarbonCummCashFlow.value = [0.0] * model.surfaceplant.plant_lifetime.value
 
         for i in range(0, model.surfaceplant.plant_lifetime.value, 1):
-            self.CarbonRevenue.value[i] = self.CarbonExtractedAnnually.value[i] * self.carbon_credit_price.value
+            # Enforce the parameterized statutory limit for tax credits
+            applicable_price = self.carbon_credit_price.value if i < self.carbon_credit_duration.value else 0.0
+
+            self.CarbonRevenue.value[i] = self.CarbonExtractedAnnually.value[i] * applicable_price
             if i == 0:
                 self.CarbonCummCashFlow.value[i] = self.CarbonRevenue.value[i]
             else:
-                self.CarbonCummCashFlow.value[i] = self.CarbonCummCashFlow.value[i - 1] + self.CarbonRevenue.value[i]
-
+                self.CarbonCummCashFlow.value[i] = self.CarbonCummCashFlow.value[i - 1] + \
+                                                   self.CarbonRevenue.value[i]
         self._calculate_derived_outputs(model)
         model.logger.info(f'Complete {str(__class__)}: {sys._getframe().f_code.co_name}')

src/geophires_x/EconomicsSam.py

@@ -678,15 +678,59 @@ def _get_single_owner_parameters(model: Model) -> dict[str, Any]:
     ret['federal_tax_rate'], ret['state_tax_rate'] = _get_fed_and_state_tax_rates(econ.CTR.value)
 
     geophires_itc_tenths = Decimal(econ.RITC.value)
-    ret['itc_fed_percent'] = [float(geophires_itc_tenths * Decimal(100))]
 
-    if econ.PTCElec.Provided:
-        ret['ptc_fed_amount'] = [econ.PTCElec.quantity().to(convertible_unit('USD/kWh')).magnitude]
+    if econ.DoSDACGTCalculations.value and geophires_itc_tenths > 0:
+        # Shield DAC CAPEX from ITC to prevent unlawful MACRS basis reduction
+        max_carbon_capacity_tonnes = max(model.sdacgteconomics.CarbonExtractedAnnually.value)
+        sdac_capex_usd = (
+            model.sdacgteconomics.CAPEX.value * model.sdacgteconomics.CAPEX_mult.value * max_carbon_capacity_tonnes
+        )
+
+        # Geothermal eligible basis = Total Installed Cost - DAC CAPEX
+        eligible_geothermal_basis_usd = ret['total_installed_cost'] - sdac_capex_usd
+        itc_fed_amount_usd = float(Decimal(eligible_geothermal_basis_usd) * geophires_itc_tenths)
 
-        ret['ptc_fed_term'] = econ.PTCDuration.quantity().to(convertible_unit('yr')).magnitude
+        ret['itc_fed_percent'] = [0.0]  # Disable percentage-based ITC on the whole project
+        ret['itc_fed_amount'] = [itc_fed_amount_usd]  # Inject fixed ITC amount for geothermal only
+    else:
+        ret['itc_fed_percent'] = [float(geophires_itc_tenths * Decimal(100))]
+
+    # Build a year-by-year schedule for the Federal Production Tax Credit
+    ptc_fed_amount_schedule = [0.0] * model.surfaceplant.plant_lifetime.value
 
-        if econ.PTCInflationAdjusted.value:
-            ret['ptc_fed_escal'] = _pct(econ.RINFL)
+    # 1. Base Electricity PTC
+    if econ.PTCElec.Provided:
+        base_ptc_rate = econ.PTCElec.quantity().to(convertible_unit('USD/kWh')).magnitude
+        ptc_term = int(econ.PTCDuration.quantity().to(convertible_unit('yr')).magnitude)
+        for i in range(min(ptc_term, model.surfaceplant.plant_lifetime.value)):
+            escalation = (1.0 + _pct(econ.RINFL) / 100.0) ** i if econ.PTCInflationAdjusted.value else 1.0
+            ptc_fed_amount_schedule[i] = base_ptc_rate * escalation
+
+    # 2. S-DAC 45Q Equivalent (Mapped as Non-Taxable PBI to avoid MACRS/Exclusivity issues)
+    if econ.DoSDACGTCalculations.value:
+        pbi_oth_amount_schedule = [0.0] * model.surfaceplant.plant_lifetime.value
+
+        for i in range(model.surfaceplant.plant_lifetime.value):
+            # The statutory duration cutoff (e.g., 12 years) is already handled inside EconomicsS_DAC_GT.py
+            # so CarbonRevenue will naturally be 0.0 for years > 12.
+            sdac_revenue_usd = model.sdacgteconomics.CarbonRevenue.value[i]
+            net_kwh_produced = model.surfaceplant.NetkWhProduced.value[i]
+
+            # Convert absolute S-DAC revenue (USD) into an equivalent USD/kWh PBI rate for SAM
+            if net_kwh_produced > 0:
+                pbi_oth_amount_schedule[i] = sdac_revenue_usd / net_kwh_produced
+
+        if any(rate > 0.0 for rate in pbi_oth_amount_schedule):
+            ret['pbi_oth_amount'] = pbi_oth_amount_schedule
+            ret['pbi_oth_term'] = model.surfaceplant.plant_lifetime.value
+            ret['pbi_oth_tax_fed'] = 0.0  # Strictly exclude from Federal taxable gross income
+            ret['pbi_oth_tax_sta'] = 0.0  # Strictly exclude from State taxable gross income
+
+    # Inject the combined array into SAM
+    if any(rate > 0.0 for rate in ptc_fed_amount_schedule):
+        ret['ptc_fed_amount'] = ptc_fed_amount_schedule
+        ret['ptc_fed_term'] = model.surfaceplant.plant_lifetime.value
+        ret['ptc_fed_escal'] = 0.0  # Escalation is already manually calculated in the array above
 
     # 'Property Tax Rate'
     geophires_ptr_tenths = Decimal(econ.PTR.value)
@@ -758,22 +802,6 @@ def _price_vector(price_value: list[float]) -> list[float | str]:
         )
         ret.append(carbon_revenue_source)
 
-    if econ.DoSDACGTCalculations.value:
-        # Pad the scalar price to match the full timeline array length required by SAM formatting
-        sdac_price_array = [0.0] * _pre_revenue_years_count(model) + [
-            model.sdacgteconomics.carbon_credit_price.value
-        ] * model.surfaceplant.plant_lifetime.value
-
-        sdac_revenue_source = CapacityPaymentRevenueSource(
-            name='S-DAC-GT Carbon credits',
-            revenue_usd=[round(it) for it in model.sdacgteconomics.CarbonRevenue.value],
-            price_label=f'S-DAC-GT Carbon credit price ({model.sdacgteconomics.carbon_credit_price.CurrentUnits.value})',
-            price=_price_vector(sdac_price_array),
-            amount_provided_label=f'S-DAC-GT Carbon Extracted ({model.sdacgteconomics.CarbonExtractedAnnually.CurrentUnits.value})',
-            amount_provided=model.sdacgteconomics.CarbonExtractedAnnually.value,
-        )
-        ret.append(sdac_revenue_source)
-
     def _get_revenue_usd_series(econ_revenue_output: OutputParameter) -> Iterable[float]:
         return [
             round(it)