AASB S2 Group 2 is mandatory now. What a downloaded NGA Factors spreadsheet doesn't give your auditor.

← All posts

Group 2's first mandatory reporting period started 1 July. Reporting under it isn't due until next year, but Scope 1 and Scope 2 data has to be audit ready from day one of the period that just began, not backfilled later, since limited assurance applies from Year 1. Somewhere in most finance and sustainability teams right now, someone has a copy of the National Greenhouse Accounts Factors workbook open in a spare tab, pulling numbers into a spreadsheet to calculate those emissions.

That workbook is free. DCCEEW publishes it every year, openly, no licence required. The problem was never getting the numbers. The problem is what happens six months from now when the external assurer asks where those numbers came from.

---

Where did that number come from?

NGA Factors vary by state and fuel type, and the variation is not small. The factor for grid electricity in Victoria is not the factor for grid electricity in Queensland. Using the wrong one is not a rounding error, it is a material misstatement, and under AASB S2 that sits with the directors, not the analyst who built the spreadsheet.

A downloaded workbook answers the calculation question. It does not answer the provenance question. Which version was downloaded. Which date. Whether the same version was used consistently across every facility and every reporting period, or whether someone updated their copy partway through the year and nobody flagged it. A spreadsheet sitting on a shared drive cannot answer any of that on its own. A person has to remember, and reporting periods are long enough that people don't.

---

What the auditor is actually checking

An assurer reviewing Scope 1 and 2 figures is not just checking arithmetic. They are checking whether the number can be traced back to an authoritative, versioned source, and whether that same source was applied consistently. That is a lineage question, not a maths question.

This is the same pattern that shows up across every AASB S2 vendor risk conversation. The data itself is rarely disputed. The ability to demonstrate where it came from and prove it has not silently drifted is where the disclosure quietly weakens.

---

The gap between free and audit ready

Free and audit ready are not the same thing, and closing that gap by hand is exactly the kind of manual process that AASB S2 was designed to put pressure on. It scales poorly across multiple facilities, multiple states, and multiple reporting periods, and it depends entirely on someone remembering to keep a paper trail for a spreadsheet nobody thought to version control.

Tech Compass publishes the same DCCEEW NGA Factors through a governed API. Every response carries the exact publication reference and version used at query time, and every call is logged, so the source can be cited precisely rather than reconstructed from memory. The full response schema is in the Climate API reference. The data doesn't change. What changes is whether the source can be proven months after the fact, on the day someone actually asks.

Group 2 entities filing this year don't get a second attempt at getting the source right. Worth checking now whether the answer to "where did that number come from" is a name, a version, and a date, or a shrug and a shared drive.