Bill / EnergyBreakdown / BillDerivation / sap_fuel were under
domain/property_baseline/ only because Baseline was built first. The Modelling
stage now needs them too, so move them (and their tests) to a neutral
domain/billing/ — Fuel/FuelRates already live in the shared domain/fuel_rates/.
Avoids a modelling -> property_baseline cross-stage import and a package name
that wrongly implies ownership (ADR-0011, ADR-0014 amendment). Pure git mv +
import rewrite across 10 files; 40 billing/baseline/repo tests pass, pyright
strict clean. CONTEXT.md Bill Derivation location updated.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The SapResult -> EnergyBreakdown adapter (ADR-0014), a classmethod on the
target mirroring Performance.from_sap_result. Folds each positive per-end-use
delivered kWh into a billable EnergyLine: main/main-2/secondary heating and
hot water at their resolved fuel (sap_code_to_fuel); lighting/pumps-fans/
appliances/cooking/cooling as electricity. PV export carries to exported_kwh
for the SEG credit. Zero-kWh end uses emit no line; a positive kWh with no
fuel code raises rather than billing at a default (strict, mirrors the
calculator).
Adds BillSection.COOLING (electricity, from space_cooling_fuel_kwh_per_yr).
BillDerivation already prices any section it is given, so no change there.
Also corrects the ADR-0014 amendment: SapResult carries the calculator's own
fuel codes (raw API or Table-32 per mapper, ADR-0015); sap_fuel normalizes.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Slice 2 of Bill Derivation. BillDerivation(fuel_rates).derive(breakdown) takes a
delivered-energy breakdown (per-section EnergyLine(section, fuel, kwh) +
exported_kwh) and produces a Bill: per-section kWh + cost, standing charges,
SEG credit, and total.
- Each end-use line billed at its fuel's unit rate.
- Standing charge added ONCE per distinct fuel used (a meter, not an end use);
off-gas fuels carry 0 so contribute nothing — no metered/unmetered special case.
- SEG export credit subtracted.
- Deterministic (ADR-0006); raises UnpricedFuel (via FuelRates) on an unpriced
fuel (e.g. heat network) rather than billing at a wrong default.
Pure domain — no calculator dependency; the SapResult->EnergyBreakdown adapter
is slice 3.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
