Scope 1 · Fugitive Methane
Oil & Gas Methane Calculator — Flaring, Venting & Fugitive CO2e (OGMP 2.0)
Compute Scope 1 methane emissions from flaring, venting, and fugitive leaks across oil and gas operations under IPCC 2019 Refinement factors, with an OGMP 2.0 reporting-level toggle and AR6/AR5 CO2e output.
Calculation basis. The calculator quantifies methane (CH4) and associated CO2 and N2O from three Scope 1 emission pathways in oil and gas operations — flaring, venting, and fugitive leaks — using emission factors from the IPCC 2019 Refinement to the 2006 Guidelines, Volume 2, Chapter 4 (Fugitive Emissions). All factors are read live from the MasterBrain oil_gas.* family; there are no fixed emission factors in the engine.
Three reporting tiers — an OGMP 2.0 toggle. The calculator is not a single fixed method. It exposes three tiers that mirror the OGMP 2.0 reporting levels, and the arithmetic differs at each:
- Generic (Level 2) — you enter segment throughput (e.g. gas produced, oil transported) and the engine multiplies by the IPCC Tier-1 factor for that segment, then auto-splits the result into venting, leaks, and flaring using the IPCC published disaggregation percentages.
- Source-specific (Level 3) — you enter per-pathway gas volumes (flared, vented, and estimated or LDAR-measured leaked volume), and the engine applies gas composition and flare destruction efficiency to each pathway independently.
- Measured (Levels 4–5) — you enter directly measured CH4 mass per pathway; the engine applies only the GWP conversion, adding no estimation layer.
Fugitive means leaked volume, not component counts. The Source-specific tier takes a leaked/vented/flared gas volume as its input — estimated, or measured through a leak-detection-and-repair (LDAR) programme. It does not use component-level emission factors (per-valve, per-flange, per-connector). Component-count methods are a planned future overlay and are out of scope in this version.
Flare slip is reported under flaring. A flare does not destroy all the methane routed to it. At the default production/processing flare destruction efficiency of 0.98, 2% of the methane passes through unburned as “flare slip.” The engine reports that slip in the flaring pathway alongside the CO2 from the 98% that combusted — it is not reclassified as venting, and it is not a separate fourth pathway.
Units do not mix. Gas-segment throughput factors are per million m3; oil-segment factors are per thousand m3; LNG import/export terminals are per station; town-gas distribution is per km. Enter each segment in its own basis. The calculator keeps segments separate for exactly this reason.
GWP basis. CO2e is reported on AR6 GWP-100 by default (fossil methane = 29.8), with an AR5 GWP-100 toggle (28.0) for historical comparison. Never mix AR5 and AR6 within one inventory. The 20-year view discussed on this page (GWP-20 = 80.8) is a prose reference, not a calculator output.
Level 2 — throughput × IPCC 2019 Refinement Tier-1 factor, split into venting / leaks / flaring by the published disaggregation.
AR6 is the current corporate-reporting default.
Audit mode exposes the full calculation chain.
Enter throughput or released volumes above to calculate
Results appear instantly. Methane mass, CO₂e, the venting / leaks / flaring split, and the full audit trail are available after calculation.
Results are indicative, intended for screening, inventory build-up, and order-of-magnitude estimates. IPCC 2019 Refinement Tier-1 factors are national-inventory averages carrying wide uncertainty ranges — for OGMP 2.0 Level 4/5 reporting, ESRS E1 / IFRS S2 disclosure, or third-party assurance under ISO 14064-3, use source-level or measured data and document your full inventory boundary and methodology. Emission factors are per million m³ (gas) or per thousand m³ (oil) at 15 °C, 101.325 kPa. GWP: AR6 GWP-100 default; AR5 provided for comparison.
Methane is the second-largest driver of warming after carbon dioxide, and the oil and gas sector is one of its largest controllable sources. But methane is also the emission most likely to be under-counted: it leaks, vents, and slips past flares in ways that a fuel-combustion inventory never captures, and its climate impact depends heavily on whether you measure it over 100 years or 20.
Get the methane number wrong and you understate your Scope 1 footprint by an order of magnitude on exactly the sources regulators now watch most closely.
Oil and gas methane emissions are calculated per pathway — flaring, venting, and fugitive leaks — as gas volume or throughput multiplied by an IPCC 2019 Refinement factor, then converted to CO2e using methane’s GWP (29.8 on AR6 GWP-100). Methane typically dominates the CO2e total.
What this calculator covers
The calculator quantifies Scope 1 methane and its associated CO2 and N2O from three emission pathways — flaring, venting, and fugitive leaks — across the oil and gas value chain, from production and processing through transmission, storage, and distribution, for both gas and oil streams.
The three pathways
Every methane emission in oil and gas operations belongs to one of three pathways, and each behaves differently:
| Pathway | What it is | How it’s quantified here | Primary mitigation |
|---|---|---|---|
| Flaring | Deliberate combustion of gas that cannot be used or sold. Converts most methane to CO2, but never all of it. | Flared volume × gas composition × flare destruction efficiency. The unburned fraction (“flare slip”) stays in the flaring line as methane. | Flare gas recovery; efficiency monitoring; routing gas to sales |
| Venting | Deliberate release of gas to atmosphere without combustion — pneumatic devices, tank flashing, blowdowns, incomplete-combustion workarounds. | Vented volume × gas composition (Source-specific tier), or the vented share of a throughput factor (Generic tier). | Vapour recovery units; electric or instrument-air pneumatics; green completions |
| Fugitive leaks | Unintended releases from equipment that should be sealed — leaking seals, valves, connectors, corroded lines. | Estimated or LDAR-measured leaked volume × gas composition. This version does not use per-component emission factors. | Leak detection and repair (LDAR); continuous monitoring; component upgrades |
Where methane sits in a Scope 1 inventory
Fugitive and vented methane is Scope 1 — direct emissions from sources the reporting company owns or controls — but it is accounted for separately from stationary and mobile combustion, because the emission mechanism is release rather than fuel burning. The GHG Protocol Scope 1 boundary includes both, but a combustion-only inventory will miss the entire fugitive and vented category. For an upstream or midstream oil and gas operator, that category is frequently the single largest line in the Scope 1 footprint on a CO2e basis, because methane’s warming potency multiplies a physically small mass into a large equivalent number.
Methane emissions are quantified as a released gas volume or a throughput, not as a fuel consumed. A tonne of vented methane is not “a tonne of gas burned inefficiently” — it is a tonne of methane released whole, carrying methane’s full GWP. This is why an oil and gas Scope 1 inventory built only from fuel-combustion factors systematically understates the true footprint.
Why methane accounting is different
Two features set methane accounting apart from the fuel-combustion accounting that dominates most Scope 1 inventories: the gap between estimation and measurement, and the sensitivity of the CO2e result to the GWP time horizon you choose.
The estimation-versus-measurement gap
For combustion, activity data is clean: you know how much fuel you burned because you bought it and metered it. For fugitive methane, the “activity” is a leak — something you did not intend and did not meter. Historically this was handled with generic emission factors: multiply throughput by a sector-average factor and accept a wide uncertainty band. But field measurement campaigns using aircraft, satellites, and site-level sensors have repeatedly found that generic factors understate real emissions, sometimes by a large margin, because a small number of “super-emitter” sources dominate and generic factors average them away.
This is the central tension the OGMP 2.0 framework was built to resolve, and it is why this calculator offers three tiers rather than one method. The generic tier is a defensible screening estimate; the measured tier reflects what a mature monitoring programme actually observes; and the gap between them is itself a decision-useful signal about where to invest in measurement.
Why CO2e depends on the GWP basis
Methane is a short-lived climate pollutant — it breaks down in the atmosphere within roughly a decade, whereas CO2 persists for centuries. That means methane’s warming impact is front-loaded: it does most of its damage soon after release. A 100-year global warming potential (GWP-100) averages that impact over a century and gives fossil methane a factor of 29.8 on the AR6 basis. A 20-year potential (GWP-20) captures the near-term impact and gives fossil methane 80.8 — about 2.71 times higher. Neither is “correct”; they answer different questions. GWP-100 is the mandated basis for corporate GHG reporting, while GWP-20 is increasingly used to communicate near-term climate urgency. The same physical tonne of methane can therefore be reported as a very different CO2e number depending on which question you are answering — a point the worked examples below make concrete.
How the calculation works — the three-tier toggle
The calculator is an OGMP 2.0 tier toggle. You pick the tier that matches the data you actually have, and the arithmetic follows. The three tiers trade off effort against fidelity, and they map directly onto the OGMP reporting levels described in the next section.
Generic (Level 2)
Enter segment throughput — gas produced, oil transported, gas processed. The engine multiplies by the IPCC Tier-1 factor for that segment and auto-splits the result into venting, leaks, and flaring using the IPCC published disaggregation. Lowest-effort screening estimate; widest uncertainty.
Source-specific (Level 3)
Enter per-pathway gas volumes — flared, vented, and estimated or LDAR-measured leaked. The engine applies gas composition and, for the flared stream, flare destruction efficiency. Reflects site-level operating detail; narrower uncertainty.
Measured (Levels 4–5)
Enter directly measured CH4 mass per pathway. The engine applies only the GWP conversion, with no estimation layer. Highest fidelity; requires a measurement programme reconciled to site-level totals.
Generic tier — throughput and disaggregation
In the Generic tier the core operation is one multiplication per segment:
CH4 emitted (tonnes) = Throughput × IPCC Tier-1 methane factor for the segment
Gas-segment throughput is entered per million m3 of gas; oil-segment throughput per thousand m3 of oil. The IPCC factor already embeds a typical split across venting, leaks, and flaring, so the engine reports not just the total but the pathway breakdown — which for most upstream gas segments is dominated by venting, with a smaller fugitive-leak share and little or no routine flaring.
Source-specific tier — per-pathway volumes and flare efficiency
In the Source-specific tier you supply the three pathway volumes directly. Each is converted to methane mass through the gas composition (the default is 90% methane by volume, at a gas density of 0.72 kg/m3, giving 0.648 kg of methane per m3 of gas). The flared stream is then reduced by the flare destruction efficiency:
Flare combusted CH4 → CO2; unburned CH4 = flared CH4 × (1 − destruction efficiency)
The default destruction efficiency is 0.98 for production and processing flares and 0.995 for refinery flares. The 2% (or 0.5%) that escapes unburned is the flare slip, and it is reported in the flaring pathway as methane — not moved into venting.
A common assumption is that a flare “handles” the methane routed to it. It does not fully. At a 98% destruction efficiency — the default for a well-operated production flare — 2% of the methane still escapes. In the Source-specific worked example below, that 2% amounts to 194 tonnes of methane from a single flare stream, which on AR6 GWP-100 is over 5,700 tCO2e. Flare slip is small as a percentage and large in absolute terms; do not treat flaring as zero-methane.
The OGMP 2.0 reporting framework
The Oil and Gas Methane Partnership 2.0 (OGMP 2.0), administered by the UN Environment Programme’s International Methane Emissions Observatory (UNEP/IMEO), is the leading international reporting framework for oil and gas methane. Its defining contribution is a five-level reporting ladder that ranks emissions estimates by how they were produced — and it explicitly rewards moving from generic factors toward direct measurement reconciled at the site level.
The organising principle of OGMP 2.0 is that measurement beats estimation. Generic emission factors are an acceptable starting point, but the framework’s highest levels require site-level measurement reconciled against source-level estimates — because that reconciliation is what surfaces the super-emitters and under-counting that generic factors hide.
The five reporting levels
Level 1
Reporting exists, but without breakdown by source. An aggregate methane number with no detail on where it comes from.
Level 2
Generic emission factors applied by source type. The Generic tier of this calculator sits here.
Level 3
Source-level specific emission factors — factors tailored to the specific equipment and operating conditions of each source. The Source-specific tier maps here.
Level 4
Site-level measurement — top-down quantification of the whole site’s emissions, capturing sources a bottom-up inventory might miss.
Level 5
Source-level measurement reconciled to site-level measurement. Bottom-up and top-down are made to agree, which is what closes the estimation gap. The Measured tier supports Level 4–5 inputs.
Level 4 versus Level 5 — the reconciliation step
The distinction between Levels 4 and 5 is the heart of the framework. Level 4 measures the site as a whole from the top down (for example, with aircraft or continuous site sensors). Level 5 additionally measures each source from the bottom up and reconciles the two — if the sum of the source-level measurements does not match the site-level total, the difference points to missing or mis-estimated sources. This reconciliation is what distinguishes a mature methane programme from one that simply reports a number, and it is the level at which the OGMP “Gold Standard” pathway operates: measurement-based reporting achieved within the framework’s stated timelines.
Reconciling bottom-up source estimates against top-down site measurement is the mechanism that surfaces the emissions generic factors average away.
GWP basis — GWP-100 versus GWP-20
Because methane is short-lived, the choice of time horizon changes its CO2e value more than for any other common greenhouse gas. The calculator reports on GWP-100 (both AR6 and AR5 available); the GWP-20 view is discussed here in prose as a cited reference.
| Basis | Fossil methane GWP | What it answers | Where it’s used |
|---|---|---|---|
| AR6 GWP-100 | 29.8 | Climate impact averaged over 100 years | Default for GHG Protocol, CSRD, CDP, SBTi corporate reporting |
| AR5 GWP-100 | 28.0 | Same horizon, earlier IPCC assessment | Historical comparison; some regulatory modes |
| AR6 GWP-20 | 80.8 | Climate impact over the near-term 20 years | Near-term urgency communication; not a corporate-reporting basis |
The AR6 GWP-100 figure for fossil methane rose from AR5’s 28.0 to 29.8, reflecting refined atmospheric science. The GWP-20 value of 80.8 is the without-climate-feedback figure that pairs consistently with the without-feedback GWP-100 basis (the with-feedback GWP-20 of 82.5 uses a different convention and should not be mixed with the 29.8 GWP-100 used here). All three values are from the IPCC Sixth Assessment Report, Working Group I.
The bar below shows the same physical quantity of methane — the 818 tonnes from the Generic-tier worked example — expressed as CO2e under each basis. The GWP-20 view is nearly triple the GWP-100 view. This is why the choice of horizon is not a technicality: it changes the headline number by a factor of roughly three.
Worked examples
Two examples, both reproducing exactly against the live calculator. The first uses the Generic tier from a single throughput figure; the second uses the Source-specific tier from three pathway volumes. Both report on AR6 GWP-100 as the headline, with the AR5 and GWP-20 views alongside.
Example A — Generic tier, gas production throughput
Input: 200 million m3/yr of onshore gas production, higher-emitting profile, default gas composition. The engine applies the IPCC Tier-1 factor for onshore high-emitting gas production and auto-splits the result across the three pathways.
| Pathway | CH4 mass | Share of CH4 |
|---|---|---|
| Venting | 728 t | 89% |
| Fugitive leaks | 90 t | 11% |
| Flaring | 0 t | 0% |
| Total CH4 | 818 t | — |
Adding the associated 290 t of CO2 and a negligible 0.005 t of N2O, and converting on AR6 GWP-100:
Methane accounts for 98.8% of the CO2e — the CO2 and N2O are almost rounding error. Viewed over 20 years, the methane alone (818 t × 80.8) is 66,094 tCO2e — the near-term climate weight of this single production stream is nearly three times its GWP-100 headline.
Example B — Source-specific tier, a multi-source asset
Input: a single asset with three measured pathway volumes — 15 million m3/yr flared, 3 million m3/yr vented, and 2 million m3/yr fugitive (LDAR-estimated leaked). Default composition (0.648 kg CH4/m3), production flare destruction efficiency 0.98.
The flared stream carries 9,720 t of methane into the flare. At 98% destruction efficiency, 9,525.6 t combusts to 26,132 t of CO2, and 194.4 t escapes as flare slip — reported in the flaring pathway as methane. Venting and fugitive leaks convert straight to methane mass:
| Pathway | CH4 mass | Share of CH4 |
|---|---|---|
| Venting | 1,944 t | 57% |
| Fugitive leaks | 1,296 t | 38% |
| Flaring (slip only) | 194.4 t | 6% |
| Total CH4 | 3,434 t | — |
| Gas | tCO2e (AR6 GWP-100) |
|---|---|
| Methane (CH4) | 102,345 (102.3 kt) |
| Carbon dioxide (CO2, flare) | 26,132 (26.1 kt) |
| N2O | 0 |
| Total | 128,477 (128.5 kt) |
Two things stand out. First, even a well-operated 98% flare emits 194 tonnes of methane here — a small percentage that becomes over 5,700 tCO2e once methane’s GWP is applied. Second, the 20-year view is stark: the methane alone (3,434 t × 80.8) is 277,500 tCO2e — 277.5 kt — and the total including the flare CO2 reaches roughly 303.6 kt. Over the horizon that matters most for near-term warming, this asset’s footprint is 2.71 times its GWP-100 methane figure.
Data quality and measurement tiers
The tier you can honestly report is set by the data you hold, and the OGMP ladder makes that explicit. Moving up the ladder is not about arithmetic — the calculator will happily convert whatever you give it — but about the provenance of the inputs.
- Bottom-up (Levels 2–3, and the source side of 5). Emissions built from throughput or per-source volumes multiplied by factors. Comprehensive in principle, but blind to sources not in the inventory and to sources emitting above their assumed factor.
- Top-down (Level 4). Emissions measured for the whole site at once — aircraft flyovers, satellite passes, continuous fence-line sensors. Captures everything the site actually emits, including sources the bottom-up inventory missed, but cannot on its own attribute emissions to specific equipment.
- Reconciled (Level 5). Bottom-up and top-down measured and made to agree. The reconciliation gap is the finding: a persistent shortfall in the bottom-up total points to a real source that estimation has been missing.
If you are early in a methane programme, start in the Generic tier for a defensible baseline, then use targeted measurement to move your largest segments to Source-specific or Measured. The value of measurement is concentrated: a small number of sources usually dominate the total, so measuring those first closes most of the estimation gap for the least effort.
Audit checklist — what assurers flag
The findings below are the issues most commonly raised when oil and gas methane inventories are reviewed under a limited or reasonable assurance engagement. Each maps to a control the calculator either enforces or makes visible.
- Flare slip excluded. Treating a flare as 100% efficient and reporting zero methane from it. At 98% efficiency the unburned 2% is real and often material — it belongs in the flaring pathway.
- GWP bases mixed. Combining AR5-basis line items with AR6-basis line items in one total. Pick one basis per inventory and state it.
- Unit bases mixed. Entering gas throughput (per million m3) and oil throughput (per thousand m3) as if interchangeable, or mixing per-station LNG factors with volumetric factors. Each segment has its own basis.
- Tier mislabelled. Reporting a generic-factor estimate as though it were measured, or claiming an OGMP level the data does not support. The reporting level must match how the number was produced.
- Composition assumed silently. Using the default 90% methane composition without disclosing it, when the actual produced-gas composition differs materially. Document the composition used.
- Fugitive presented as component-counted. Describing a leaked-volume estimate as a component-level (per-valve, per-connector) inventory. This calculator uses leaked volume; do not overstate the method.
Reporting context — OGMP, IPCC, GHG Protocol, EU, EPA
Oil and gas methane disclosure now sits across a methodology layer, an accounting layer, and a growing set of regulatory regimes. The frameworks below are the ones an operator will typically navigate.
| Framework | Role | Type |
|---|---|---|
| OGMP 2.0 (UNEP/IMEO) | The methane reporting framework. Defines the five-level reporting ladder and the measurement-reconciliation principle. | Voluntary reporting framework |
| IPCC 2019 Refinement | The emission-factor source. Volume 2, Chapter 4 supplies the fugitive-emission factors this calculator reads. | Scientific methodology |
| GHG Protocol Scope 1 | The accounting standard. Places fugitive and vented methane inside the Scope 1 boundary. | Accounting standard |
| IPCC AR6 | The GWP values source. Supplies the 29.8 (GWP-100) and 80.8 (GWP-20) fossil-methane potentials. | Scientific basis |
| EU Methane Regulation | Regulation (EU) 2024/1787, in force since August 2024. Sets measurement, reporting, and verification requirements for methane in the EU energy sector, including imports. | Regulation |
| US EPA Subpart W | The US greenhouse gas reporting rule for petroleum and natural gas systems, amended for recent reporting years to strengthen methane quantification. | Regulation (reporting) |
The EU Methane Regulation and US EPA Subpart W are cited here as context, not linked, because GreenCalculus does not yet publish a dedicated standards page for either. Note that the US Waste Emissions Charge — the fee mechanism established under the Inflation Reduction Act, distinct from Subpart W reporting — was subject to Congressional action in 2025; confirm its current status independently before treating it as an active charge. OGMP 2.0 itself is likewise cited rather than linked, pending a standards page.
For operators whose methane sits in coal rather than hydrocarbons, the sibling Coal Mine Methane Calculator applies the same IPCC 2019 Refinement chapter to seam gas liberated during and after mining. Both are part of the fugitive-emissions calculator family, alongside the F-Gas Inventory Aggregator for refrigerant and process-gas leaks.
Data sources and factor versioning
All emission factors are read live from the MasterBrain oil_gas.* family; the engine holds no fixed factors, only fail-soft mirrors of the live values for the case where the data layer is briefly unavailable.
| Input | Source | Basis |
|---|---|---|
| Fugitive emission factors (26 segment rows, gas and oil) | IPCC 2019 Refinement, Vol 2 Ch 4 | Per-segment methane factors with venting/leak/flare disaggregation |
| Flare destruction efficiency | IPCC 2019 Refinement | 0.98 production/processing · 0.995 refinery |
| Default gas composition | IPCC 2019 Refinement | 90% CH4 by volume · 0.72 kg/m3 density |
| Methane GWP | IPCC AR6 WGI | 29.8 (GWP-100, AR6) · 28.0 (GWP-100, AR5) · 80.8 (GWP-20, without feedback) |
Segment factors span gas production, processing, transmission, storage, and distribution, and oil production and transport — from higher- and lower-emitting onshore production through offshore, coal-bed methane, LNG terminals, and town-gas networks. Each is expressed in its native basis: gas segments per million m3, oil segments per thousand m3, LNG terminals per station, and town-gas distribution per km. The GWP values are stable until the next IPCC assessment. The calculator stamps each result with the MasterBrain version used, so a figure computed today remains reconcilable against a later factor vintage.
Frequently asked questions
Flaring is deliberate combustion of gas — it converts most methane to CO2 but leaves a small unburned “slip.” Venting is deliberate release of gas to atmosphere without combustion, so the methane escapes whole. Fugitive emissions are unintended leaks from equipment that should be sealed. The calculator treats all three as separate pathways because they emit differently: flaring produces mostly CO2 plus a little methane slip, while venting and fugitive leaks are almost entirely methane.
No. The Source-specific tier takes a leaked gas volume — estimated or measured through a leak-detection-and-repair (LDAR) programme — not a per-valve, per-flange, or per-connector count. Component-level emission factors are a planned future overlay and are not part of this version. If your data is a component inventory, convert it to a total leaked volume before entering it.
Because methane’s global warming potential is far higher than CO2‘s — 29.8 times on the AR6 GWP-100 basis. A physically small mass of methane becomes a large CO2e number once the GWP is applied. In the Generic worked example methane is 98.8% of the total; even in the Source-specific example, where a flare produces substantial CO2, methane is still 79.7%. For most oil and gas operations, methane is the pathway that decides the Scope 1 footprint.
0.98 for production and processing flares, and 0.995 for refinery flares, both from the IPCC 2019 Refinement. That means 2% (or 0.5%) of the methane routed to the flare escapes unburned as flare slip. The engine reports that slip in the flaring pathway as methane, alongside the CO2 from the portion that combusted. It is not reclassified as venting and it is not a separate pathway.
For corporate GHG reporting — GHG Protocol, CSRD, CDP — use GWP-100 (29.8 on AR6). GWP-20 (80.8) is used to communicate near-term climate urgency and is not a corporate-reporting basis. They answer different questions: GWP-100 averages methane’s impact over a century, GWP-20 captures the front-loaded near-term impact. The calculator reports on GWP-100; the GWP-20 view is roughly 2.71 times higher for the same tonne of methane, and this page shows that comparison so you can communicate both without mixing them in your inventory.
Generic (OGMP Level 2) multiplies segment throughput by an IPCC Tier-1 factor and auto-splits the result into venting, leaks, and flaring. Source-specific (Level 3) takes per-pathway volumes and applies gas composition and flare efficiency. Measured (Levels 4–5) takes directly measured methane mass per pathway and applies only the GWP conversion. Pick the tier that matches the data you actually hold — the calculator does not let you claim a higher-fidelity method than your inputs support.
The IPCC 2019 Refinement to the 2006 Guidelines, Volume 2, Chapter 4 (Fugitive Emissions), covering 26 segment rows across gas production, processing, transmission, storage, and distribution, plus oil production and transport. All factors are read live from the MasterBrain rather than fixed, so the calculator always computes against the current factor vintage, and each result is stamped with the version used.
Because their factors use different bases. Gas-segment factors are expressed per million m3 of gas; oil-segment factors per thousand m3 of oil; LNG terminals per station; town-gas distribution per km. Combining them would silently misapply a factor by three orders of magnitude. Enter each segment in its own basis and let the calculator sum the resulting emissions, not the raw throughputs.
Both are regulatory regimes that require methane quantification and reporting — the EU Methane Regulation (Regulation (EU) 2024/1787, in force since August 2024) for the EU energy sector including imports, and US EPA Subpart W for US petroleum and natural gas systems. This calculator produces an IPCC-factor-based inventory that can inform those filings, but each regime has its own specific requirements. Treat the calculator output as a screening and internal-reporting tool, and confirm the exact quantification method each regulation demands before submitting.
It refers to achieving measurement-based reporting — OGMP Levels 4 and 5, where site-level measurement is reconciled against source-level estimates — within the framework’s stated timelines. It is the mature end of the reporting ladder, where an operator no longer relies on generic factors for its material sources but measures them and reconciles bottom-up and top-down figures. The Measured tier of this calculator supports the Level 4–5 inputs that pathway requires.
Yes, in absolute terms. A 98% destruction efficiency sounds like near-complete combustion, but the 2% that escapes is methane at full potency. In the Source-specific worked example, a single flare stream slips 194 tonnes of methane — over 5,700 tCO2e on AR6 GWP-100. Reporting a flare as zero-methane understates the footprint on exactly the source many operators assume is fully controlled.