Map fuel code 39 (electricity, any tariff) to standard electricity

modelling_e2e properties with main fuel 39 failed at the price boundary
(UnpricedFuelCode since #44fff767; previously mis-rated as non-electric →
the ~14-SAP over-rating flagged in earlier review).

Code 39 is SAP Table 12 "electricity, any tariff" (epc_codes.csv main_fuel 39 =
"electricity, unspecified tariff"; spec footnote (j): defines an electric system,
cost/CO2/PE = standard electricity). It was absent from API_FUEL_TO_TABLE_32, so
to_table_32_code(39) was None → is_electric_fuel_code(39) False and pricing
raised.

Fix: map API_FUEL_TO_TABLE_32[39] = 30 (standard electricity) — the canonical
place Khalim's fuel work added codes. One line makes classification, pricing,
CO2/PE and the billing carrier all agree (39 → 30 → ELECTRICITY).

Tests: to_table_32_code(39)==30, is_electric_fuel_code(39) True, price == standard
electricity, and the billing carrier resolves to ELECTRICITY. 0 corpus impact
(no lodged corpus cert uses 39); accuracy + mapper-corpus gates green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

domain/sap10_calculator/tables/table_32.py

@@ -107,6 +107,12 @@ API_FUEL_TO_TABLE_32: Final[dict[int, int]] = {
     10: 30, 11: 42, 12: 43, 13: 44, 14: 11, 15: 12, 16: 22, 17: 9,
     18: 75, 19: 76, 20: 51, 21: 52, 22: 53, 23: 55, 24: 54, 25: 41,
     26: 1, 27: 2, 28: 4, 29: 30, 30: 42, 31: 43, 32: 44, 33: 11,
+    # SAP Table 12 code 39 = "electricity, any tariff" (epc_codes.csv main_fuel
+    # 39 = "electricity, unspecified tariff"; spec footnote (j): defines an
+    # electric system, cost/CO2/PE = standard electricity). Resolve to standard
+    # electricity (30) so it classifies as electric and prices at the standard
+    # rate — otherwise it now raises UnpricedFuelCode (was: mis-rated non-electric).
+    39: 30,
 }
 
 # Gov-API `main_fuel_type` enum codes whose value COLLIDES with a

tests/domain/billing/test_sap_fuel.py

@@ -43,6 +43,7 @@ def test_table_32_codes_map_to_their_billing_fuel(code: int, fuel: Fuel) -> None
         (0, Fuel.ELECTRICITY),  # API "electricity" -> Table 32 code 30
         (25, Fuel.HEAT_NETWORK),  # API community heat -> Table 32 code 41
         (14, Fuel.COAL),  # API house coal -> Table 32 code 11
+        (39, Fuel.ELECTRICITY),  # "electricity, any tariff" -> Table 32 code 30
     ],
 )
 def test_raw_api_fuel_codes_normalize_before_mapping(api_code: int, fuel: Fuel) -> None:

tests/domain/sap10_calculator/test_table_32.py

@@ -339,3 +339,19 @@ def test_additional_standing_charges_zero_for_oil_only() -> None:
 
     # Assert
     assert standing == 0.0
+
+
+def test_electricity_any_tariff_code_39_resolves_to_standard_electricity() -> None:
+    # SAP Table 12 code 39 = "electricity, any tariff" (epc_codes.csv main_fuel 39
+    # = "electricity, unspecified tariff"; spec footnote (j): defines an electric
+    # system, cost = standard tariff). It must classify as electric and price at
+    # the standard-electricity rate — without the mapping it raises UnpricedFuelCode
+    # and is_electric_fuel_code(39) is False (mis-rated as non-electric).
+    from domain.sap10_calculator.tables.table_32 import (
+        is_electric_fuel_code,
+        to_table_32_code,
+    )
+
+    assert to_table_32_code(39) == 30
+    assert is_electric_fuel_code(39) is True
+    assert unit_price_p_per_kwh(39) == unit_price_p_per_kwh(30)