Methodology · Calculator Versioning
Carbon Calculator Versions
Every tCO2e figure published by Terminal Carbon is produced by a versioned calculation engine. The version is stamped onto each MRV calculation row so buyers, auditors and host-country regulators can reproduce results exactly. Below is the public registry of engines, with formulas, changelogs and methodology alignment.
Released 2026-05-05
Initial production engine for grid-connected solar PV. Computes tCO2e from interval meter data and a versioned grid emission factor, with completeness, gap and capacity-factor sanity checks.
Core formula
tCO2e = (Σ kWh / 1000) × EF[tCO2/MWh]. kWh prefers kwh_exported (conservative) and falls back to kwh_generated. Intervals are clipped to the reporting window before summation.
Changelog
- Interval-aware kWh aggregation with window clipping (no double-count across reporting periods).
- Conservative metering: prefer exported kWh over gross generation when both present.
- Completeness % = covered_hours / expected_hours (capped at 100%).
- Sanity flags: completeness < 90%, capacity factor > 35% or < 8% (after 24h coverage).
- Versioned grid emission factor lookup (mrv_grid_emission_factors).
- Engine version persisted on every calculation row (calc_engine_version).
Methodology alignment
- CDM AMS-I.D — Grid connected renewable electricity generation
- CDM ACM0002 — Grid-connected electricity generation from renewable sources
- Verra VM0001 / VCS Standard v4.7 — monitoring & QA principles
Reproducing a published number
Each mrv_calculations row stores its calc_engine_version, the grid emission factor it used, the input meter readings and the resulting tCO2e. Pair the engine entry above with that row to reproduce the exact result.