OGMP 2.0 Level 4 and Level 5 Reporting Explained

Methane reporting under OGMP 2.0, the Oil and Gas Methane Partnership 2.0, is voluntary, yet EU methane law now builds on it. Regulation (EU) 2024/1787, the European Union’s (EU) methane law for the energy sector, entered into force on 4 August 2024 [1]. Its measurement and reporting rules are built on OGMP 2.0, and its requirements reach importers as well as producers [1]. In October 2026 the European Commission published draft reporting templates and proposed one-year delays to importer MRV and to importer and EU-producer methane-intensity duties [1].

OGMP 2.0, the Oil and Gas Methane Partnership 2.0, is the United Nations Environment Programme’s voluntary methane reporting framework for the industry [2]. It sorts emissions data into five levels, and the top two, Level 4 and Level 5, ask where the number came from [3]. Level 4 reporting means source-level estimates specific to the operator’s own equipment, built from measurement, engineering calculation, or process simulation [3]. Level 5 reporting adds a measurement of the whole site, reconciles it statistically with the source-level estimate, and reports the uncertainty that remains [3].

Gold Standard is the OGMP 2.0 reporting status awarded yearly; it requires Level 4/5 for operated assets within three years, plus a credible implementation plan [4]. The OGMP 2.0 Level 5 Assessment counted 238 assets reporting at Level 5 in 2024, or 7 per cent of global production [5]. The hard part is rarely the measurement itself. The hard part is explaining why the measurement disagrees with the inventory.

This guide is for emissions and reporting teams at operators planning the move from Level 3 toward Gold Standard. It covers, in order, what the five levels require, what changes between Level 4 and Level 5, and where factor-based inventories fall short. That last section uses Colorado’s statewide study as its worked example, because its authors describe it as the largest aerial data collection of its kind. It ends with where TetraSoft MAES, our platform for the Mechanistic Air Emissions Simulator, a physics-based emissions model, fits, then common questions [6].

Quick Answer: OGMP 2.0 Level 4 requires source-level emission estimates built from measurement, engineering calculation, or process simulation instead of generic factors. Level 5 adds site-level measurement of the same asset plus a statistical reconciliation of the two estimates [3]. Gold Standard Reporting requires Level 4/5 reporting for all material assets within set deadlines, backed by a credible implementation plan [4]. The deadline is three years for operated assets and five for non-operated ventures [2].

What the Five OGMP 2.0 Reporting Levels Require

The five levels move along two different axes, and confusing them can lead operators to misjudge how far they are from Gold Standard. Levels 1 to 3 refine scope, narrowing the unit of accounting from an asset, to an emission category, to an individual emission source [3]. Levels 3 to 5 refine the measurement itself, moving from a generic factor to source measurement to site-level measurement with a stated uncertainty [3].

Read the table down the last two columns rather than across the rows. The unit of accounting holds at the emission source from Level 3 to Level 4, while the measurement basis keeps changing through Level 5 [3].

Level	Unit of accounting	What the estimate is built from	Specific to your own equipment?	Site-level measurement?
1	Country, venture, asset, or facility	Activity factor times a generic emission factor	No	No
2	Emission category, such as venting or flaring	Generic factor specific to that category	No	No
3	Individual emission source	Generic source-level emission factors	No	No
4	Individual emission source	Measurement-based factors, engineering calculation, process simulation, or other TGD methods	Yes, from sampled measurement or calculation, not a census	No
5	Whole site, reconciled against sources	Sum of Level 4 estimates reconciled with site-level measurement	Yes	Yes

Two things follow from the last two columns. Levels 1 to 3 rest on generic emission factors or generic calculations, so they are closer to bookkeeping than to measurement [3]. Level 4 is where emission estimates must become specific to the company or asset rather than generic [3]. Level 5 adds independent site-level measurement, reconciled against the sum of Level 4 source estimates [3].

A company sitting at Level 3 has already done the hard inventory work of naming every source. What it has not done is replace the generic factor attached to each one [3]. That substitution is the core of the step, which guidance pairs with documented methods and uncertainty estimates for each measured or calculated emission.

The 14 Core Emission Sources That Define Level 3

Level 3 reporting is organized around 14 core emission sources named by the framework [3]. In our grouping, seven are operational: gas well hydraulic fracturing, oil well casinghead, purging and venting, incidents and malfunctions, liquids unloading, incomplete combustion, flare efficiency [3]. The other seven are equipment: reciprocating and centrifugal compressors, leaks, unstabilized liquid storage tanks, underground pipe leaks and permeation, pneumatic devices, and glycol dehydrators [3].

That list is worth reading as a checklist rather than a taxonomy. An operator that cannot produce an activity count for one of the 14 has a gap that Level 4 will expose rather than fix.

How OGMP 2.0 and the EU Rule Have Changed Since 2014

The framework and the law built on it have both moved since launch, with the latest entries below from October 2026.

Date	What happened	Source
2014	The Climate and Clean Air Coalition launches the original OGMP	UNEP OGMP 2.0, Frequently Asked Questions
23 November 2020	OGMP 2.0 launches with 62 companies holding about 30% of world oil and gas production	European Commission, Oil and gas industry commits to new framework to monitor, report and reduce methane emissions, 23 November 2020
4 August 2024	Regulation (EU) 2024/1787 enters into force, with measurement and reporting built on OGMP 2.0	European Commission, Energy, Methane emissions
March 2026	Level 5 Assessment counts 238 Level 5 assets in 2024	UNEP OGMP 2.0, OGMP 2.0 Level 5 Assessment, March 2026
20 July 2026	Commission recommendations on optional model clauses and on penalties for importer obligations	European Commission, Energy, Methane emissions
9 October 2026	Draft implementing regulation with reporting templates published	European Commission, Energy, Methane emissions
14 October 2026	Commission proposes one-year delay to importer MRV and methane-intensity requirements	European Commission, Energy, Methane emissions

The European Parliament backed longer delays on 22 October and talks with the Council follow; until an amendment is adopted, current dates stand.

What Actually Changes Between Level 4 and Level 5

Level 4 is a statement about your own equipment, and Level 5 is a statement about whether that equipment list adds up. At Level 4 the framework accepts measurement-based emission factors drawn from a representative sample, the results of engineering calculations, and the results of process simulation [3]. Each source can use any method the technical guidance accepts for it, so methods can differ from source to source [3].

Level 5 then measures the site as a whole and compares that against the sum of the Level 4 estimates [3]. The framework asks for a statistical analysis that determines the best consolidated estimate and its uncertainty [3]. It also asks operators to understand any discrepancy between the estimates, to improve reporting [3]. Findings may then be extrapolated to similar facilities operating under similar conditions [3].

Reconciliation Is the Part That Fails

The reconciliation step is where Level 5 gets expensive, because the two estimates rarely agree. The framework asks operators to understand and report that gap, not just fold it into a consolidated number. A site-level measurement above the source-level sum, beyond their combined uncertainty, suggests sources the inventory misses or underestimates, unless measurement timing explains it.

Explaining that gap often means revising the source-level model, though the site-level method, its time window and its uncertainty can also cause it. Likely culprits include conditions factor-based inventories do not adequately account for, such as equipment failure conditions and variations in throughput [7].

What You Need in Hand Before Attempting Level 5

Four inputs have to exist before a Level 5 attempt is worth funding. Each one feeds the reconciliation step. The first is a complete equipment inventory at the source level, which is the Level 3 foundation [3]. The second is throughput data, because a source-level model responds to what actually moved through the facility.

The third is gas composition for the streams involved, since methane is a fraction of what a source releases and that fraction shifts by facility [7]. The fourth is the site-level measurement campaign itself, which no amount of operational record-keeping can substitute for. Colorado’s statewide program obtained its site-level data from aerial survey vendors flying more than 30,000 individual facility scans [8].

Where Factor-Based Inventories Fall Short

Top-down measurements generally suggest that factor-based inventories underestimate emissions, partly because rare large emitters and incomplete activity data escape them [8]. Colorado’s statewide study represents, in its updated final report’s words, the largest data collection of its kind: aerial data over upstream facilities [8]. It is worth reading closely, because it was built on operator-reported equipment and production records, the inputs any source-level inventory starts from.

Colorado is the worked example because its health department commissioned a statewide comparison of the reported inventory with aerial measurement [8]. Operators in Texas, New Mexico or any other state pursuing Level 5 face the same test, because the levels are defined by method, not jurisdiction.

On 2024 data for the facilities MAES modelled, the measurement-informed total plus maintenance was 1.47 times the reported inventory (38,936 against 26,415 tonnes a year) [8]. Two MAES figures come out of that work, and they answer different questions; a separate statistical model gives higher ratios. Both totals in that headline ratio include the same 2,339 tonnes a year of reported maintenance emissions [8].

The second comparison sets maintenance emissions aside, because the model does not represent them [8]. Against that adjusted inventory of 24,076 tonnes a year, the measurement-informed total of 36,597 sits 52 per cent higher [8]. The report attributes that increment to failure events, though it counts large tank emissions regardless of cause and books unknown sources as miscellaneous [8]. The same pattern appears from orbit, as covered in Why Satellites Show About 2x More Methane Than Inventories.

Reconciliation Needs a Mechanism, Not Just a Number

Level 5 does not ask an operator to produce a bigger number [3]. It asks them to reconcile a source-level inventory against a site-level measurement, which means accounting for why the two differ [3]. A reconciliation that closes the gap with an unexplained scaling factor satisfies the arithmetic and not the requirement.

A measurement-informed inventory addresses this problem by combining bottom-up estimates with overlapping measurements, attributing the excess to equipment types [8]. It matches a model to the reported inventory, then adds aerial-detected emissions the inventory lacked, from three vendors with different detection limits [8]. Each detection is attributed to a cause before it is included [8].

The value of that exercise is not the ratio it produces. It is that the model breaks additional emissions out by equipment type and failure type, which serves Level 5’s requirement to understand discrepancies [8].

The mechanism is what makes that attribution possible. The model represents equipment in failed states rather than only in design states [8]. That lets the gap resolve into failure modes by equipment type, though some excess stays in a miscellaneous large-emitter category [8]. Failure modes are not the whole of it, because a reporting rule can also leave real sources out of scope.

Subpart W is the US Environmental Protection Agency’s greenhouse-gas reporting rule for oil and gas facilities emitting 25,000 metric tons CO2-equivalent or more yearly [9]. EPA proposed in September 2025 to suspend Subpart W reporting until reporting year 2034; that proposal is not final [10].

Until EPA’s May 2024 amendments, Subpart W omitted produced water tanks and crankcase vents; the 2024 state inventory in that comparison also omitted crankcase vents. Both sat outside the reported total while still emitting. An operator reading that has somewhere to go next, because a failure mode is something to find and fix.

Some states keep their own oil and gas inventory alongside the federal rule. Colorado operators also file a state inventory, the Oil and Natural Gas Annual Emission Inventory Report (ONGAEIR), by June 30 each year [11]. It rests on state regulation, so a change to the federal rule does not by itself end it.

Two practical cautions belong with it. Reconciliation is not a formality applied after the measurement campaign, and treating it as one is how Level 5 timelines slip. Different methods applied to the same measurements can also produce materially different totals, so the method and its assumptions are part of what gets reported [8].

Where TetraSoft MAES Fits

Process simulation is one of the methods the framework accepts at Level 4 [3]. That is the opening a simulator fills, provided its Level 4 method incorporates measurement as OGMP guidance expects.

TetraSoft MAES is a simulator of that kind: a mechanistic model of facility emissions [6]. It is a product an operator can run directly, on their own facilities and their own schedule [6]. An operator loads a facility’s equipment inventory and operating parameters in MAES Studio, and assigns its gas composition in MAES Project Manager [6].

The platform then runs the Monte Carlo simulation of that configuration in the cloud [6]. No field measurement hardware is needed for a baseline run, because the inputs are equipment, composition, and operating records rather than new field data [6].

Two properties matter to whoever assures the submission. The platform estimates emissions from fluid flow through equipment and equipment states, plus activity data multiplied by emission factor distributions [7]. Mechanistic results trace back to modelled fluid flow and equipment states; factor-based results rest on empirical emission-factor distributions [7]. The methodology is described in peer-reviewed papers, so a third party can review its approach and assumptions, though reproducing a result needs the engine [7].

The measurement-informed inventory method itself is peer reviewed, published in 2025 in ACS ES&T Air, an American Chemical Society environmental science journal [12]. That paper describes using the simulator to integrate inventory and aerial estimates, characterising failure events with site-specific information [12].

Under the hood it applies two methods rather than one [7]. Flares and heaters are modelled mechanistically, as are failure states driven by fluid flow through equipment, such as a stuck dump valve [8]. What the flare model assumes, and how far real units fall from it, is set out in Oil and Gas Flaring: What Flares Actually Destroy.

Activity-times-factor methods, using emission-factor distributions, handle the remaining sources such as component leaks; those factors must be measurement-based to count at Level 4 [8]. Both sides represent failure states: mechanistic models simulate equipment malfunctions directly, while factor-based sources use failure-emission distributions [8]. A comparable component-level treatment of triethylene glycol (TEG) dehydrators, the units that dry gas with liquid glycol, is described in Glycol Pumps: 90% of Uncontrolled TEG Dehydrator Emissions.

The simulation engine was developed at Colorado State University and the University of Texas at Austin [6]. TetraSoft provides commercial access to it through a licence with Colorado State [6]. It is the same engine used for the Colorado statewide work cited throughout this post [8]. The state health department commissioned that statewide application of the engine to inform its intensity rule; that is not regulatory approval of the platform.

Simulation can carry much of the Level 4 work, but OGMP guidance expects each source’s Level 4 method to incorporate measurement in its development. Feeding site-level measurements into the same model, once detections the inventory missed are attributed to causes, is what produces a measurement-informed inventory [12]. That is the reconciliation half of Level 5, not a substitute for it.

Gold Standard Reporting still requires reconciling source-level data with site-level measurements for all material assets, within the prescribed timelines [5]. The measurement campaign is the part a model cannot replace, and the model is the part a measurement cannot supply on its own.

What the Platform Produces Before Any Survey

The model-only case earns its keep before any survey is flown. It ranks a site’s own equipment by contribution, so an operator can see which sources dominate their total rather than assuming [6]. That ranking is what makes mitigation spending targetable, because the largest contributor is named rather than inferred.

The platform also puts a number on it [13]. It runs a financial analysis over the simulated results, valuing the modelled gas loss at a reference Henry Hub price as an annual figure [13]. It then splits that total into the share available technology can remove and the share it cannot [13]. Heater firing and the flare combustion floor sit on the non-addressable side [13].

Tank thief-hatch leaks and gas-driven glycol pump flash sit on the addressable side, each carrying the action that removes it [13]. Replacing thief hatch gaskets and seals, and swapping a gas-driven glycol pump for an electric one, are two such actions [13]. The same analysis ranks sites by addressable methane in descending order, as a site priority ranking for mitigation [13].

The walkthrough above scrolls the whole analysis, from the headline gas-value and recovery figures through the per-source mitigation actions to the site ranking [13].

The same ranking can feed the materiality assessment that decides where site-level measurement is worth paying for. That matters when a survey campaign has to be scoped across a fleet rather than a single pad.

What comes back is not a single number [6]. The platform returns a P5, mean, and P95 distribution across dozens of interactive plots in several results tabs [6]. P5 and P95 are the 5th and 95th percentiles, so 90 per cent of simulated outcomes fall between them. The plots break out which equipment types contribute most and how failure events move the profile [6].

Emissions from failure modes are reported as a category distinct from routine baseline emissions [6]. The split arrives as an output of the run rather than something assembled by hand afterwards.

Explaining the Gap Between Your Inventory and the Aerial Number

The reconciliation problem an operator actually faces is narrow. A survey vendor returns a site-level number, it disagrees with the sum of source-level estimates, and the operator has to understand why [3]. The platform is built for that comparison directly [6]. It sets a MAES-based facility estimate against the inventory already reported to a regulator, and shows where the difference sits [6].

The difference lands on equipment, which is what makes it actionable. MAES models wells, separators, tanks and tank batteries, compressors, heaters, flares, dehydrators, vapour recovery units and pneumatics, some mechanistically and others from emission-factor distributions [6]. It also models abnormal events, including stuck dump valves, pressure relief valve actuations, thief hatch failures, and vent failures [6].

In MAES modelling, failure conditions such as stuck dump valves affected the ethane-to-methane (C2/C1) ratio, which could vary by 2.15 times depending on facility configuration [14]. That kind of signature narrows an unexplained gap toward the equipment able to produce it, giving inspectors a short list.

One limitation belongs in any honest plan. In the Colorado work the model could only be run for 81 per cent of operating reported facilities [8]. The remaining 19 per cent were missing key information in the reported data [8]. Gaps in the reported data, not the model, limited coverage, although MAES’s own input requirements set which gaps disqualified a facility.

Frequently Asked Questions

Is OGMP 2.0 mandatory?

OGMP 2.0 is a voluntary partnership that companies join, rather than a regulation that applies automatically [2]. Members commit to setting a reduction target, reporting annually, and improving data quality over time [2]. The commitments apply once a company signs the membership MoU, and OGMP 2.0 conducts independent assurance on implementation plans and reported data [5]. Separately, Regulation (EU) 2024/1787, which is binding EU law, builds on the relevant parts of the framework [1].

What is OGMP 2.0 Gold Standard Reporting?

Gold Standard Reporting is awarded to companies pursuing the highest reporting level, which is Level 5 [5]. It requires reconciliation of source-level emissions data with site-level measurements, within the prescribed timelines, for all material assets [5]. Material assets are those accounting for 95 per cent of a given operator’s total emissions, so the obligation is weighted rather than universal [5]. Companies have three years to reach it for operated assets and five years for non-operated ventures [5].

Who are the OGMP 2.0 members, and how many assets reach Level 5?

OGMP 2.0 has grown to 163 member companies covering 43 per cent of global oil and gas production [15]. Membership spans upstream, midstream, and downstream operators, including public, private, and national oil and gas companies [2].

In 2024, assets at Level 5 accounted for 7 per cent of global production, corresponding to 238 assets [5]. Those assets reported a methane intensity of around 0.1 per cent in energy terms [5].

How does OGMP 2.0 relate to the EU Methane Regulation?

Regulation (EU) 2024/1787 builds on the relevant parts of the OGMP 2.0 framework, though its operator reporting rules speak of source-level and site-level quantification [16]. Its recitals describe source-level reporting as beginning at level 3, level 4 as requiring direct measurements, and level 5 as requiring complementary site-level measurements [16]. The practical consequence is that OGMP 2.0 Level 5 reporting, with independent third-party verification, is one route to show the equivalence importers must demonstrate. Producers selling into the EU have no direct duty under its import rules but face them through EU buyers, partnership members or not [16].

Does Level 4 require measuring every single source?

No, because the framework accepts measurement-based emission factors derived from a representative sample rather than a census [3]. Engineering calculations and process simulation results are also accepted at Level 4 [3]. What the framework does not accept at Level 4 is a generic factor that is not specific to the operator’s own equipment [3]. The accepted methodology is specified source by source in the technical guidance documents [3].

Interested in building a Measurement-Informed Inventory for your operations? Contact us to learn about our MAES-based estimation services.

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References

1. European Commission, Energy, Methane emissions. https://energy.ec.europa.eu/topics/carbon-management-and-fossil-fuels/methane-emissions_en
2. UNEP OGMP 2.0 Module 1, Introduction to OGMP 2.0 reporting and mitigation framework, August 2025. https://www.ogmpartnership.org/sites/default/files/resources/2025-08/OGMP%20module%20-%201.pdf
3. UNEP OGMP 2.0 Module 2, The OGMP 2.0 reporting levels, August 2025. https://www.ogmpartnership.org/sites/default/files/resources/2025-08/OGMP%20module%20-%202.pdf
4. UNEP OGMP 2.0, Frequently Asked Questions. https://www.ogmpartnership.org/frequently-asked-questions
5. UNEP OGMP 2.0, OGMP 2.0 Level 5 Assessment, March 2026. https://www.ogmpartnership.org/sites/default/files/resources/2026-03/OGMP%202.0%20Level%205%20Assessment.pdf
6. TetraSoft, MAES Platform. https://tetrasoftco.com/maes-platform/maes-landing.html
7. Mollel et al., ACS ES&T Air 2025, 2, 723-735, DOI 10.1021/acsestair.4c00168. Using Prototypical Oil and Gas Sites to Model Methane Emissions in Colorado’s Denver-Julesburg Basin Using a Mechanistic Emission Estimation Tool. https://doi.org/10.1021/acsestair.4c00168
8. Brown et al., Colorado Ongoing Basin Emissions (COBE) Updated Final Report, November 20, 2025. Colorado State University METEC and Colorado School of Mines, for the Colorado Department of Public Health and Environment. https://hdl.handle.net/10217/242813
9. US EPA, Subpart W: Petroleum and Natural Gas Systems. https://www.epa.gov/ghgreporting/subpart-w-petroleum-and-natural-gas-systems
10. US EPA, Reconsideration of the Greenhouse Gas Reporting Program, 90 FR 44591, September 16, 2025. https://www.federalregister.gov/documents/2025/09/16/2025-17923/reconsideration-of-the-greenhouse-gas-reporting-program
11. Colorado Department of Public Health and Environment, Oil and Natural Gas Annual Emission Inventory Reporting. https://cdphe.colorado.gov/ongaeir
12. Santos et al., ACS ES&T Air 2025, 2, 1598-1611, DOI 10.1021/acsestair.5c00089. Using Measurement-Informed Inventory to Assess Emissions in the Denver-Julesburg Basin. https://doi.org/10.1021/acsestair.5c00089
13. TetraSoft, MAES Results, Financial Impact tab. In-product feature of the MAES Results application, checked 5 November 2026.
14. Colorado State University METEC, Mechanistic Air Emissions Simulator. https://metec.colostate.edu/mechanistic-air-emissions-simulator/
15. Oil and Gas Methane Partnership website, 2026 Report: From measurement to mitigation, 15 October 2026. https://www.ogmpartnership.org/
16. Regulation (EU) 2024/1787 of 13 June 2024 on the reduction of methane emissions in the energy sector. https://eur-lex.europa.eu/eli/reg/2024/1787/oj/eng
17. European Commission, Oil and gas industry commits to new framework to monitor, report and reduce methane emissions, 23 November 2020. https://commission.europa.eu/news-and-media/news/oil-and-gas-industry-commits-new-framework-monitor-report-and-reduce-methane-emissions-2020-11-23_en

This post is for informational purposes only and does not constitute legal or compliance advice. Consult qualified legal counsel or a compliance professional for guidance specific to your operations and jurisdiction.