Slice 39: PV credit input boundary uses RdSAP10 Table 32 + DE22 PV fixture

`_pv_export_credit_gbp_per_kwh` previously read from `prices.unit_price`
(SAP10.2 Table 12 code 60 = 5.59 p/kWh) while the actual rating
cascade inside _fuel_cost reads from `table_32_unit_price_p_per_kwh`
(RdSAP10 Table 32 code 60 = 13.19 p/kWh, same as standard electricity).
The exposed CalculatorInputs.pv_export_credit_gbp_per_kwh therefore
misled about what the cascade applied. The calculator's fallback path
at calculator.py:442 fires for synthetic inputs without `fuel_cost`
and would compute the wrong PV credit by reading the misleading input.

Per ADR-0010 §10 the rating cascade uses Table 32 prices. Unified
both code paths on Table 32 so the input boundary reports the same
13.19 p/kWh the cascade applies. Cert-path math unchanged (cert path
always sets fuel_cost). Synthetic/fallback path now consistent with
cert path.

Also adds cert 2130-1033-4050-5007-8395 (DE22, end-terrace + 1 ext,
gas combi PCDB 17505, 2× 2.04 kWp PV) as 9th golden fixture. First
PV-bearing cert in the cohort. Pinned residual is SAP +8 / PE −61 /
CO2 +0.19 — spec-version drift not a code bug (cert was scored by
SAP10.2 software using Table 12 PV export 5.59 p/kWh = £194 credit
→ SAP 82; calc targets RdSAP10 Table 32 = 13.19 p/kWh = £457 credit
→ SAP 90). Both internally consistent against their own price table.
The PE residual is amplified because PV gen also offsets PE via
inputs.other_primary_factor, which scales with gen kWh independently
of the export-credit price.

930/930 Elmhurst cascade green. 14/14 golden cohort + 1 new
cert_to_inputs unit test green. Pyright net-zero (49 errors before
and after).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

packages/domain/src/domain/sap/rdsap/cert_to_inputs.py

@@ -698,11 +698,15 @@ def _pv_generation_kwh_per_yr(epc: EpcPropertyData) -> float:
     return total_kwp * _PV_ANNUAL_YIELD_KWH_PER_KWP
 
 
-def _pv_export_credit_gbp_per_kwh(prices: PriceTable) -> float:
+def _pv_export_credit_gbp_per_kwh() -> float:
-    """PV cost credit per kWh generated. SAP 10.2 Table 12 code 60 (PV
+    """PV cost credit per kWh generated. Per ADR-0010 §10 the rating
-    export to grid) — 5.59 p/kWh on the spec table, 13.19 p/kWh under
+    cascade uses RdSAP10 Table 32 prices; code 60 (PV export to grid)
-    cert calibration (legacy unit prices)."""
+    = 13.19 p/kWh (same as standard electricity — PV gen displaces
-    return prices.unit_price_p_per_kwh(_PV_EXPORT_TARIFF_CODE) * _PENCE_TO_GBP
+    grid imports at the standard rate). The legacy SAP 10.2 Table 12
+    value (5.59 p/kWh) is no longer the target and is intentionally
+    not read here, so the CalculatorInputs boundary reports the same
+    rate _fuel_cost applies internally."""
+    return table_32_unit_price_p_per_kwh(_PV_EXPORT_TARIFF_CODE) * _PENCE_TO_GBP
 
 
 def _other_fuel_cost_gbp_per_kwh(
@@ -2178,7 +2182,7 @@ def cert_to_inputs(
             _STANDARD_ELECTRICITY_FUEL_CODE,
         ),
         pv_generation_kwh_per_yr=_pv_generation_kwh_per_yr(epc),
-        pv_export_credit_gbp_per_kwh=_pv_export_credit_gbp_per_kwh(prices),
+        pv_export_credit_gbp_per_kwh=_pv_export_credit_gbp_per_kwh(),
         secondary_heating_fraction=secondary_fraction_value,
         secondary_heating_efficiency=secondary_efficiency_value,
         energy_requirements=energy_requirements_result,

packages/domain/src/domain/sap/rdsap/tests/fixtures/golden/2130-1033-4050-5007-8395.json

@@ -0,0 +1,453 @@
+{
+  "uprn": 100030334057,
+  "roofs": [
+    {
+      "description": "Pitched, 300 mm loft insulation",
+      "energy_efficiency_rating": 5,
+      "environmental_efficiency_rating": 5
+    },
+    {
+      "description": "Pitched, 100 mm loft insulation",
+      "energy_efficiency_rating": 3,
+      "environmental_efficiency_rating": 3
+    }
+  ],
+  "walls": [
+    {
+      "description": "Solid brick, as built, no insulation (assumed)",
+      "energy_efficiency_rating": 1,
+      "environmental_efficiency_rating": 1
+    },
+    {
+      "description": "Solid brick, with internal insulation",
+      "energy_efficiency_rating": 4,
+      "environmental_efficiency_rating": 4
+    }
+  ],
+  "floors": [
+    {
+      "description": "Suspended, no insulation (assumed)",
+      "energy_efficiency_rating": 0,
+      "environmental_efficiency_rating": 0
+    },
+    {
+      "description": "Solid, no insulation (assumed)",
+      "energy_efficiency_rating": 0,
+      "environmental_efficiency_rating": 0
+    }
+  ],
+  "status": "entered",
+  "tenure": 3,
+  "window": {
+    "description": "Fully double glazed",
+    "energy_efficiency_rating": 2,
+    "environmental_efficiency_rating": 2
+  },
+  "addendum": {
+    "addendum_numbers": [
+      8
+    ]
+  },
+  "lighting": {
+    "description": "Excellent lighting efficiency",
+    "energy_efficiency_rating": 5,
+    "environmental_efficiency_rating": 5
+  },
+  "postcode": "DE22 3RW",
+  "hot_water": {
+    "description": "From main system",
+    "energy_efficiency_rating": 4,
+    "environmental_efficiency_rating": 4
+  },
+  "post_town": "DERBY",
+  "psv_count": 0,
+  "built_form": 3,
+  "created_at": "2025-07-24 16:36:27",
+  "door_count": 2,
+  "region_code": 6,
+  "report_type": 2,
+  "sap_heating": {
+    "number_baths": 1,
+    "cylinder_size": 1,
+    "shower_outlets": [
+      {
+        "shower_outlet": {
+          "shower_wwhrs": 1,
+          "shower_outlet_type": 1
+        }
+      }
+    ],
+    "number_baths_wwhrs": 0,
+    "water_heating_code": 901,
+    "water_heating_fuel": 26,
+    "cylinder_thermostat": "N",
+    "main_heating_details": [
+      {
+        "has_fghrs": "N",
+        "main_fuel_type": 26,
+        "boiler_flue_type": 2,
+        "fan_flue_present": "Y",
+        "heat_emitter_type": 1,
+        "emitter_temperature": 1,
+        "main_heating_number": 1,
+        "main_heating_control": 2106,
+        "main_heating_category": 2,
+        "main_heating_fraction": 1,
+        "central_heating_pump_age": 0,
+        "main_heating_data_source": 1,
+        "main_heating_index_number": 17505
+      }
+    ],
+    "immersion_heating_type": "NA",
+    "has_fixed_air_conditioning": "false"
+  },
+  "sap_version": 10.2,
+  "sap_windows": [
+    {
+      "pvc_frame": "true",
+      "glazing_gap": "16+",
+      "orientation": 8,
+      "window_type": 1,
+      "glazing_type": 3,
+      "window_width": {
+        "value": 0.95,
+        "quantity": "m"
+      },
+      "window_height": {
+        "value": 1.75,
+        "quantity": "m"
+      },
+      "draught_proofed": "true",
+      "window_location": 0,
+      "window_wall_type": 1,
+      "permanent_shutters_present": "N",
+      "permanent_shutters_insulated": "N"
+    },
+    {
+      "pvc_frame": "true",
+      "glazing_gap": "16+",
+      "orientation": 8,
+      "window_type": 1,
+      "glazing_type": 3,
+      "window_width": {
+        "value": 0.95,
+        "quantity": "m"
+      },
+      "window_height": {
+        "value": 1.7,
+        "quantity": "m"
+      },
+      "draught_proofed": "true",
+      "window_location": 0,
+      "window_wall_type": 1,
+      "permanent_shutters_present": "N",
+      "permanent_shutters_insulated": "N"
+    },
+    {
+      "pvc_frame": "true",
+      "glazing_gap": "16+",
+      "orientation": 4,
+      "window_type": 1,
+      "glazing_type": 3,
+      "window_width": {
+        "value": 1,
+        "quantity": "m"
+      },
+      "window_height": {
+        "value": 1.7,
+        "quantity": "m"
+      },
+      "draught_proofed": "true",
+      "window_location": 0,
+      "window_wall_type": 1,
+      "permanent_shutters_present": "N",
+      "permanent_shutters_insulated": "N"
+    },
+    {
+      "pvc_frame": "true",
+      "glazing_gap": "16+",
+      "orientation": 4,
+      "window_type": 1,
+      "glazing_type": 3,
+      "window_width": {
+        "value": 0.95,
+        "quantity": "m"
+      },
+      "window_height": {
+        "value": 1.7,
+        "quantity": "m"
+      },
+      "draught_proofed": "true",
+      "window_location": 0,
+      "window_wall_type": 1,
+      "permanent_shutters_present": "N",
+      "permanent_shutters_insulated": "N"
+    },
+    {
+      "pvc_frame": "true",
+      "glazing_gap": "16+",
+      "orientation": 6,
+      "window_type": 1,
+      "glazing_type": 3,
+      "window_width": {
+        "value": 0.7,
+        "quantity": "m"
+      },
+      "window_height": {
+        "value": 0.9,
+        "quantity": "m"
+      },
+      "draught_proofed": "true",
+      "window_location": 0,
+      "window_wall_type": 1,
+      "permanent_shutters_present": "N",
+      "permanent_shutters_insulated": "N"
+    },
+    {
+      "pvc_frame": "true",
+      "glazing_gap": "16+",
+      "orientation": 6,
+      "window_type": 1,
+      "glazing_type": 3,
+      "window_width": {
+        "value": 0.65,
+        "quantity": "m"
+      },
+      "window_height": {
+        "value": 0.5,
+        "quantity": "m"
+      },
+      "draught_proofed": "true",
+      "window_location": 0,
+      "window_wall_type": 1,
+      "permanent_shutters_present": "N",
+      "permanent_shutters_insulated": "N"
+    }
+  ],
+  "schema_type": "RdSAP-Schema-21.0.1",
+  "uprn_source": "Energy Assessor",
+  "country_code": "ENG",
+  "main_heating": [
+    {
+      "description": "Boiler and radiators, mains gas",
+      "energy_efficiency_rating": 4,
+      "environmental_efficiency_rating": 4
+    }
+  ],
+  "air_tightness": {
+    "description": "(not tested)",
+    "energy_efficiency_rating": 0,
+    "environmental_efficiency_rating": 0
+  },
+  "dwelling_type": "End-terrace house",
+  "language_code": 1,
+  "pressure_test": 4,
+  "property_type": 0,
+  "address_line_1": "5 Lynton Street",
+  "assessment_type": "RdSAP",
+  "completion_date": "2025-07-24",
+  "inspection_date": "2025-07-18",
+  "extensions_count": 1,
+  "measurement_type": 1,
+  "open_flues_count": 0,
+  "total_floor_area": 64,
+  "transaction_type": 1,
+  "conservatory_type": 1,
+  "heated_room_count": 4,
+  "other_flues_count": 0,
+  "registration_date": "2025-07-24",
+  "sap_energy_source": {
+    "mains_gas": "Y",
+    "meter_type": 2,
+    "pv_connection": 2,
+    "photovoltaic_supply": [
+      [
+        {
+          "pitch": 2,
+          "peak_power": 2.04,
+          "orientation": 4,
+          "overshading": 1
+        }
+      ],
+      [
+        {
+          "pitch": 2,
+          "peak_power": 2.04,
+          "orientation": 8,
+          "overshading": 2
+        }
+      ]
+    ],
+    "wind_turbines_count": 0,
+    "gas_smart_meter_present": "false",
+    "is_dwelling_export_capable": "true",
+    "wind_turbines_terrain_type": 2,
+    "electricity_smart_meter_present": "true"
+  },
+  "secondary_heating": {
+    "description": "None",
+    "energy_efficiency_rating": 0,
+    "environmental_efficiency_rating": 0
+  },
+  "closed_flues_count": 0,
+  "extract_fans_count": 1,
+  "lzc_energy_sources": [
+    11
+  ],
+  "sap_building_parts": [
+    {
+      "identifier": "Main Dwelling",
+      "wall_dry_lined": "N",
+      "wall_thickness": 230,
+      "floor_heat_loss": 7,
+      "roof_construction": 4,
+      "wall_construction": 3,
+      "building_part_number": 1,
+      "sap_floor_dimensions": [
+        {
+          "floor": 0,
+          "room_height": 2.64,
+          "floor_insulation": 1,
+          "total_floor_area": 28.2,
+          "party_wall_length": 8.27,
+          "floor_construction": 2,
+          "heat_loss_perimeter": 13.38
+        },
+        {
+          "floor": 1,
+          "room_height": 2.58,
+          "total_floor_area": 28.2,
+          "party_wall_length": 8.27,
+          "heat_loss_perimeter": 15.09
+        }
+      ],
+      "wall_insulation_type": 4,
+      "construction_age_band": "B",
+      "party_wall_construction": 1,
+      "wall_thickness_measured": "Y",
+      "roof_insulation_location": 2,
+      "roof_insulation_thickness": "300mm",
+      "wall_insulation_thickness_measured": 100
+    },
+    {
+      "identifier": "Extension 1",
+      "wall_dry_lined": "N",
+      "floor_heat_loss": 7,
+      "roof_construction": 5,
+      "wall_construction": 3,
+      "building_part_number": 2,
+      "sap_floor_dimensions": [
+        {
+          "floor": 0,
+          "room_height": 2.5,
+          "floor_insulation": 1,
+          "total_floor_area": 7.21,
+          "party_wall_length": 0,
+          "floor_construction": 1,
+          "heat_loss_perimeter": 9.88
+        }
+      ],
+      "wall_insulation_type": 3,
+      "construction_age_band": "B",
+      "party_wall_construction": "NA",
+      "wall_thickness_measured": "N",
+      "roof_insulation_location": 2,
+      "roof_insulation_thickness": "100mm",
+      "wall_insulation_thickness": "measured",
+      "wall_insulation_thickness_measured": 100,
+      "wall_insulation_thermal_conductivity": 1
+    }
+  ],
+  "boilers_flues_count": 0,
+  "open_chimneys_count": 0,
+  "solar_water_heating": "N",
+  "habitable_room_count": 4,
+  "heating_cost_current": {
+    "value": 939,
+    "currency": "GBP"
+  },
+  "insulated_door_count": 0,
+  "co2_emissions_current": 2.7,
+  "energy_rating_average": 60,
+  "energy_rating_current": 82,
+  "lighting_cost_current": {
+    "value": 45,
+    "currency": "GBP"
+  },
+  "main_heating_controls": [
+    {
+      "description": "Programmer, room thermostat and TRVs",
+      "energy_efficiency_rating": 4,
+      "environmental_efficiency_rating": 4
+    }
+  ],
+  "blocked_chimneys_count": 0,
+  "has_hot_water_cylinder": "false",
+  "heating_cost_potential": {
+    "value": 591,
+    "currency": "GBP"
+  },
+  "hot_water_cost_current": {
+    "value": 161,
+    "currency": "GBP"
+  },
+  "mechanical_ventilation": 0,
+  "percent_draughtproofed": 100,
+  "schema_version_current": "LIG-21.0",
+  "suggested_improvements": [
+    {
+      "sequence": 1,
+      "typical_saving": 290,
+      "indicative_cost": "\u00a37,500 - \u00a311,000",
+      "improvement_type": "Q",
+      "improvement_details": {
+        "improvement_number": 7
+      },
+      "improvement_category": 5,
+      "energy_performance_rating": 91,
+      "environmental_impact_rating": 76
+    },
+    {
+      "sequence": 2,
+      "typical_saving": 58,
+      "indicative_cost": "\u00a35,000 - \u00a310,000",
+      "improvement_type": "W1",
+      "improvement_details": {
+        "improvement_number": 57
+      },
+      "improvement_category": 5,
+      "energy_performance_rating": 92,
+      "environmental_impact_rating": 79
+    }
+  ],
+  "co2_emissions_potential": 1.6,
+  "energy_rating_potential": 92,
+  "lighting_cost_potential": {
+    "value": 45,
+    "currency": "GBP"
+  },
+  "schema_version_original": "LIG-21.0",
+  "hot_water_cost_potential": {
+    "value": 161,
+    "currency": "GBP"
+  },
+  "renewable_heat_incentive": {
+    "water_heating": 2166.19,
+    "space_heating_existing_dwelling": 10128.81
+  },
+  "draughtproofed_door_count": 2,
+  "energy_consumption_current": 232,
+  "has_fixed_air_conditioning": "false",
+  "multiple_glazed_proportion": 100,
+  "calculation_software_version": "10.2.2.0",
+  "energy_consumption_potential": 138,
+  "environmental_impact_current": 65,
+  "cfl_fixed_lighting_bulbs_count": 0,
+  "current_energy_efficiency_band": "B",
+  "environmental_impact_potential": 79,
+  "led_fixed_lighting_bulbs_count": 9,
+  "has_heated_separate_conservatory": "false",
+  "potential_energy_efficiency_band": "A",
+  "co2_emissions_current_per_floor_area": 43,
+  "incandescent_fixed_lighting_bulbs_count": 0
+}

packages/domain/src/domain/sap/rdsap/tests/test_cert_to_inputs.py

@@ -394,6 +394,23 @@ def test_calculator_always_uses_uk_average_weather_for_rating() -> None:
     assert inputs_default.region == 0
 
 
+def test_pv_export_credit_input_reports_rdsap10_table_32_rate() -> None:
+    # Arrange — per ADR-0010 the rating cascade uses RdSAP10 Table 32
+    # prices (code 60 = 13.19 p/kWh for PV export). The CalculatorInputs
+    # boundary must report the same rate _fuel_cost applies internally
+    # so synthetic consumers (and the calculator's fallback path) don't
+    # see a different number from what the cascade produces. Previously
+    # this read from SAP10.2 Table 12 (5.59 p/kWh), leaving the input
+    # boundary out of step with the cascade.
+    epc = _typical_semi_detached_epc()
+
+    # Act
+    inputs = cert_to_inputs(epc)
+
+    # Assert
+    assert abs(inputs.pv_export_credit_gbp_per_kwh - 0.1319) <= 1e-6
+
+
 def test_open_chimneys_raise_infiltration_ach() -> None:
     # Arrange — Direction check: chimneys add Table 2.1 volume to the
     # infiltration calc, so an otherwise identical dwelling with 2 open

packages/domain/src/domain/sap/rdsap/tests/test_golden_fixtures.py

@@ -132,6 +132,26 @@ _EXPECTATIONS: tuple[_GoldenExpectation, ...] = (
         expected_co2_resid_tonnes_per_yr=-0.2234,
         notes="Semi-detached, TFA 102, age C, gas PCDB-listed.",
     ),
+    _GoldenExpectation(
+        cert_number="2130-1033-4050-5007-8395",
+        actual_sap=82,
+        expected_sap_resid=+8,
+        expected_pe_resid_kwh_per_m2=-61.2533,
+        expected_co2_resid_tonnes_per_yr=+0.1856,
+        notes=(
+            "End-terrace + 1 extension, TFA 64, gas combi PCDB index 17505, "
+            "postcode DE22 (PCDB Table 172 match), PV: 2× 2.04 kWp arrays "
+            "(SE + NE). Cert scored under SAP10.2 software (Table 12 PV "
+            "export = 5.59 p/kWh, £194 PV credit → SAP 82). Our calc "
+            "targets RdSAP10 (Table 32 PV export = 13.19 p/kWh, £457 PV "
+            "credit → SAP 90) per ADR-0010. The +8 SAP / −61 PE residual "
+            "is spec-version drift, not a code bug — both calcs are "
+            "internally consistent against their own price table. The PE "
+            "residual is amplified because PV generation also offsets PE "
+            "via inputs.other_primary_factor; that offset scales with the "
+            "PV gen kWh, not the export-credit price."
+        ),
+    ),
     _GoldenExpectation(
         cert_number="0390-2254-6420-2126-5561",
         actual_sap=65,
@@ -221,6 +241,7 @@ _PCDB_CHAIN_EXPECTATIONS: tuple[tuple[str, int, float], ...] = (
     ("0300-2747-7640-2526-2135", 17992, None),   # gas PCDB-listed
     ("8135-1728-8500-0511-3296", 17702, None),   # gas PCDB-listed
     ("0390-2254-6420-2126-5561", 18119, None),   # LN12 gas combi PCDB-listed
+    ("2130-1033-4050-5007-8395", 17505, None),   # DE22 gas combi PCDB-listed + PV
 )