Which emission factors you use depends on what you are reporting. For NGER reporting, the only valid source is the NGER Measurement Determination as in force for the year you are reporting. For other purposes, such as a voluntary inventory or Scope 3 estimates, the National Greenhouse Accounts (NGA) Factors are the matching government source.
Key points
- NGER reports must use the Measurement Determination as in force for the reporting year
- The Determination is updated every year and factors are never carried forward
- 2025-26 NGER reports are due by 31 October 2026
- 2026-27 uses the Determination as amended by the 2026 Update
- DCCEEW states NGA Factors should not be used for NGER reporting
- AASB S2 requires disclosure of the measurement approach, inputs and assumptions
NGER reporting uses the Measurement Determination for that year
The Clean Energy Regulator states that the Measurement Determination is updated each year and that companies should use the version that matches the year they are reporting for. Factors are never carried forward from a previous year.
Two reporting years are live at the same time for most of the year. NGER reports for 2025-26 are due by 31 October 2026 and use the Determination as amended for 2025-26. Activity from 1 July 2026 falls in the 2026-27 reporting year, which uses the Determination as amended by the NGER (Measurement) Amendment (2026 Update) Determination 2026.
NGA Factors are for estimates outside NGER
DCCEEW publishes the NGA Factors each year. Each edition draws on the Measurement Determination and replaces the previous edition. DCCEEW states that the NGA Factors should not be used to meet reporting requirements under the NGER Act, but that companies can apply them to a broader range of emissions estimates. NGER reports cover Scope 1 and Scope 2 emissions only, so this includes most Scope 3 estimates.
| Purpose | Factor source | 2025-26 | 2026-27 |
|---|---|---|---|
| NGER report | NGER Measurement Determination | Determination as in force for 2025-26 | Determination as amended by the 2026 Update |
| Estimates outside NGER | NGA Factors | NGA Factors 2025 | NGA Factors 2026 |
What this means for AASB S2
AASB S2 paragraph 29(a)(iii) requires an entity to disclose the measurement approach, inputs and assumptions it uses to measure its greenhouse gas emissions. Whichever factor source and edition you use, it should be stated for each reporting year so that the figures can be traced and assured.
References & sources
Primary regulatory documents and authoritative references underpinning this answer.
- Clean Energy Regulator: NGER legislative frameworkcer.gov.au
- NGER (Measurement) Determination 2008, all versionslegislation.gov.au
- DCCEEW: National Greenhouse Accounts Factors 2026dcceew.gov.au
- DCCEEW: National Greenhouse Accounts Factors 2025dcceew.gov.au
- Clean Energy Regulator: Report emissions and energycer.gov.au
- AASB S2 Climate-related Disclosures (September 2024)standards.aasb.gov.au