Cost — methodology¶
The Cost theme aggregates CfD payments over time and compares them against a gas counterfactual. Three methodology pieces live here: (a) how cost totals are aggregated, (b) allocation-round handling for forward projections, (c) the link to the shared gas-counterfactual.
Aggregation¶
Cost totals are monthly sums of CFD_Payments_GBP + reference_price × CFD_Generation_MWh (the two cash-flow channels consumers pay through — levy top-ups + wholesale-embedded cost). Weekly/daily aggregation uses calendar-week or calendar-day sums; monthly uses calendar months (pd.to_datetime(...).dt.to_period("M")). Allocation round is preserved as a grouping key.
Allocation round handling¶
Charts by allocation round group units via Allocation_round from the LCCC portfolio snapshot. Each round (Investment Contract, AR1, AR2, AR3, AR4) has its own cost profile because strike prices differ. Remaining-obligations projections extend each unit's current strike forward to its contract end date.
Gas counterfactual¶
The "gas alternative" line used across Cost charts is computed identically to Efficiency's denominator. See the single shared source of truth:
→ Gas counterfactual (shared methodology)
Cited constants (all carry Provenance: blocks — grep -rn "^Provenance:" src/):
CCGT_EFFICIENCY(0.55) — BEIS Electricity Generation Costs 2023GAS_CO2_INTENSITY_THERMAL(0.184 tCO₂/MWh thermal) — DESNZ GHG factorsCCGT_EXISTING_FLEET_OPEX_PER_MWH(£5/MWh) — BEIS EGC 2023 Table ES.1DEFAULT_CARBON_PRICES(2018–2026 annual) — UK ETS / EU ETS auction results
Full definitions: src/uk_subsidy_tracker/counterfactual.py.