Base standards
These are always on, for every client.
| Standard | Role in the platform |
|---|---|
| GHG Protocol Corporate Standard | Organisational boundaries, scopes, base year and recalculation |
| GHG Protocol Scope 2 Guidance (2015) | Dual location-based and market-based reporting. The guidance is under revision, so methods are versioned. |
| ISO 14064-1:2018 and ISO 14064-3:2019 | Inventory design, uncertainty and documentation; readiness for third-party verification |
| IPIECA / API / IOGP guidelines | Oil & gas boundaries, joint-venture and equity accounting, source categories |
| API Compendium (2021) | Main calculation methods and emission factors per source type |
| IPCC 2006 Guidelines and 2019 Refinement | Fallback default emission factors |
| IPCC AR6 / AR5 GWP100 | Selectable global warming potential sets |
EmitLedger is aligned with these standards and designed to support verification to ISO 14064-3. It does not replace your verifier, and you remain responsible for official regulatory submissions.
Method tiers
Each emission source records the data-quality tier of its method, so you can see, and improve, the mix across your portfolio.
| Tier | Approach | Example |
|---|---|---|
| T4 · Measured | Direct measurement, CEMS or metered vent | Ultrasonic flare meter with online gas chromatograph |
| T3 · Site-specific calculation | Metered activity with site gas composition | Fuel gas meter with monthly gas analysis |
| T2 · Source-type factor | API Compendium factor per equipment type | Pneumatic device count × factor |
| T1 · Default factor | IPCC default | Diesel litres × IPCC default factor |
Method registry
Every method has a code and a version. Results keep the exact version used, so a method change never silently rewrites history.
| Method | Sources |
|---|---|
COMB_GAS_MB_V1 | Gaseous fuel: carbon mass balance on gas composition; CH₄ and N₂O by energy content |
COMB_LIQUID_NCV_V1 | Liquid fuels and mobile combustion: net calorific value × emission factor |
FLARE_COMP_V1 | Flaring: composition and combustion efficiency, per stream (routine, non-routine, purge and pilot) |
VOLUME_COMP_V1 | Vented whole gas: volume × composition |
ELEC_DUAL_V1 | Purchased electricity: location-based and market-based, with certificate allocation |
BLOWDOWN_PVT_V1 | Depressurisation events from pressure, temperature, isolated volume and compressibility |
AMINE_CO2_MB_V1 | Acid gas removal CO₂ vent by mass balance |
COUNT_EF_V1 | Pneumatic devices, components and seals: count × factor × hours |
MASS_TOPUP_V1 | Refrigerants, SF₆ and fire suppression agents by mass balance |
LOADING_EF_V1 | Crude loading and offloading |
FUGITIVE_LDAR_V1 | Measured leaks from LDAR surveys, with leak duration between surveys |
HEAT_STEAM_V1 | Purchased heat, steam and cooling |
Units and reference conditions
Values are stored exactly as entered, with their units. Gas volumes always carry their reference conditions, whether standard (15 °C, 101.325 kPa), normal (0 °C) or US standard (60 °F), and are converted to moles before any formula is applied. Standard and normal cubic metres differ by about 5.5%, a common source of silent error in spreadsheets.
Emission factors
- Libraries: API Compendium, IPCC, UK DESNZ, US EPA and grid factors, each row carrying its reference and licence.
- Your own factors: site-specific or asset-specific factors override the library.
- Resolution order: source-specific, then asset, then tenant-wide, then country, then global, filtered by validity date. If two candidates tie, the engine reports it instead of picking one.
- Verification status: library values are marked verified only after they are checked against the source document, and results that use unverified factors are flagged.
- Releases and pinning: factors, methods and packs ship as versioned library releases. Each reporting year is pinned to a release, and upgrading shows the impact first.
GWP and CO₂e
Results are stored as mass per gas. CO₂e is calculated when you report, with the GWP set selected for that reporting year (AR4, AR5 or AR6, 100-year). The same data can be reported with AR5 values to one programme and AR6 values to another.
Consolidation
Operational control (100% of operated assets), equity share (time-versioned equity percentage per asset), or both. The platform stores both views.
Uncertainty
Uncertainty is propagated with IPCC Approach 1 and reported together with its coverage, so a figure is never shown with more confidence than the data supports.
Regulatory packs
A pack is a versioned rule set layered on the base standards: mandatory source categories, minimum method tiers, GWP set, thresholds, units and reference conditions, verification rules and report format. Packs are switched on per asset, with presets suggested from the asset’s country.
Quality assurance
- Golden tests: fixed worked examples run against the engine on every change.
- Pure, deterministic engine: the same inputs always give the same outputs.
- Independent review: a third-party methodology review is planned before general availability.