Glossary›Emissions accounting and measurement›NGA Factors (National Greenhouse Accounts)
Glossary term
Cluster D · D13
Tier 1 · differentiator
NGA Factors (National Greenhouse Accounts)
Definition
The National Greenhouse Accounts Factors are the Australian Government’s published emission factors for fuels, electricity by state and territory, waste and other common activities, updated annually by the Department of Climate Change, Energy, the Environment and Water. They are the default factor set for Australian corporate emissions estimates. They must not be used to meet reporting obligations under the NGER Act.
DCCEEW
· National Greenhouse Accounts Factors, annual edition · published guidance, not a legislative instrument
On this page
In practice
This is the most-used document in Australian carbon accounting and the one most frequently used wrongly, in a specific and consequential way.
The standing caution. The NGA Factors are for estimating emissions for purposes other than NGER reporting. DCCEEW states the position directly: the factors must not be used to meet reporting requirements under the National Greenhouse and Energy Reporting Act 2007. An entity registered under NGER calculates its NGER emissions using the NGER Measurement Determination, not the NGA Factors document. The two are related (the NGA Factors draw on the Measurement Determination) but they are not interchangeable, and the difference bites in two directions.
Your position
What the NGA Factors are for you
An NGER reporter
Your NGER submission must be on the NGER basis. Using NGA Factors for that return is non-compliant.
An NGER reporter also preparing an AASB S2 disclosure
You now have two figures that can legitimately differ, and you need to decide which basis your statutory climate disclosure runs on and say so. AASB S2 permits a method other than the GHG Protocol where a jurisdictional authority requires one, and the NGER Measurement Determination is that other method. Two Australian entities of the same size can report on different bases and both be compliant. What is not defensible is running two bases inside one entity and not disclosing which produced the disclosed figure.
Not an NGER reporter
The NGA Factors are the right default and there is no serious competing Australian factor set for Scope 1 and Scope 2.
The structure worth knowing. The document separates factors by scope, so the same fuel appears with a Scope 1 combustion factor and a Scope 3 extraction-and-transport factor. Electricity carries a state-and-territory Scope 2 factor and a separate Scope 3 factor covering transmission and distribution losses and upstream fuel extraction. Reporters who take only the Scope 2 figure and omit the Scope 3 electricity line have a Category 3 gap that is trivially visible.
The update cycle. A new edition publishes annually, and state electricity factors move meaningfully year to year as grids decarbonise. That has a consequence people miss: a business whose consumption is flat will report falling Scope 2 purely because the grid factor fell. That is a real change in emissions and it is correctly reported, but it is not a result of anything the business did, and a board paper that presents it as performance is misleading its own directors.
What the assurer does with it
The assurer’s first question is which edition, and their second is whether one edition was applied consistently across the whole period and the whole inventory. A model built over several months frequently picks up two editions because whoever built the later sheets downloaded the current version.
They then look up a sample of factors in the cited edition and re-perform the calculation. This is a direct documentary test with a binary outcome.
They accept the NGA Factors of a stated edition, applied by state where the factor is state-specific, applied consistently across the period, and cited in the basis of preparation. They reject a mixed-edition model, a national average factor applied to a business with concentrated state exposure, and (the one that catches NGER reporters) NGA Factors used to produce a figure that is also being presented as an NGER-basis number.
Where the entity is an NGER reporter, the assurer will ask for the NGER submission and reconcile it to the disclosed figures. Differences are expected and are not findings in themselves. An unexplained difference, or a basis of preparation that does not disclose which method was used, is a finding.
Commonly confused with
The NGER Measurement Determination, which is the legislative instrument governing NGER reporting and is the thing an NGER reporter must actually apply. Also confused with the National Greenhouse Gas Inventory, which is Australia’s national-level emissions account and is a different document with a different purpose.
Timing and relief
A new edition publishes each year. The edition current at the time an inventory is built is the one to use, and it should be named in the basis of preparation with its year. Set a calendar reminder rather than a habit: a factor set applied by muscle memory is how a superseded edition survives into a current report.
Sources
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2
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National Greenhouse and Energy Reporting Act 2007 (Cth), sections 11 and 11A
Federal Register of Legislation
Review status
Review required
Last reviewed
15 September 2026
Editorial pass, unsigned
Reviewer required
Carbon accounting specialist
Next scheduled review
1 August 2027
next expected National Greenhouse Accounts Factors release
Part of
Cluster D, Emissions accounting and measurement
49 terms from the head term carbon accounting down to individual Scope 3 categories and the mechanics of factors, boundaries and data quality. The largest cluster in the glossary.
Related terms
The general concept the NGA Factors are the Australian default for
The physical quantity the factors are applied to
The conversion the NGA Factors have already applied for you
Related questions
Where do Australian emission factors come from?
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The National Greenhouse Accounts Factors, published each year by the Department of Climate Change, Energy, the Environment and Water. They give Scope 1 factors by fuel and Scope 2 electricity factors by state and territory. NGER-registered corporations must use NGER measurement methods for their NGER reporting.
We have sites in several states. Does that change our emission factors?
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Yes, for electricity. Location-based Scope 2 factors differ by state and territory because grid intensity differs, so you need electricity consumption split by site and state and then the matching factor for each. Scope 1 fuel factors are national and do not change from one state to another.
We report under NGER. Does that automatically capture us?
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It can. If you are a corporation registered under the NGER Act and your Scope 1 and Scope 2 emissions are at or above the 50,000 tonne CO2-e publication threshold, you are in Group 1. Every other registered NGER corporation sits in Group 2, regardless of size.
Where this sits commercially
Carbonhalo names the factor edition in the basis of preparation and applies one edition across the whole period, which is the finding most first-year models fail on.
Other terms in this cluster
NGA Factors (National Greenhouse Accounts)