NGER vs AASB S2: Running Dual Frameworks Without Doubling...

Somewhere right now, a compliance manager at an Australian construction company is maintaining two separate emissions models in two separate spreadsheets. One is set up for the NGER report due 31 October. The other is structured around the four-pillar AASB S2 disclosure that needs to go into the annual report. Both models draw from the same pile of diesel invoices, electricity bills, and gas receipts. But the numbers don't match - and they're not supposed to.

That's the part nobody warned you about when ASRS mandatory reporting kicked in. If you're a construction company already reporting under NGER, you didn't just get a second framework. You got a second framework that uses different GWP values, covers a broader scope of emissions, demands forward-looking scenario analysis, and runs on a different reporting calendar. The raw data is identical. The outputs are not.

We've spent years building carbon accounting systems for companies dealing with exactly this mess. Before Carbonly, our team worked inside enterprise data platforms at large ASX-listed mining and energy companies - BHP, Rio Tinto, Senex Energy - where NGER reporting was business as usual. What we're seeing now with the AASB S2 overlay is a different kind of problem. It's not that the second framework is hard on its own. It's that running both simultaneously, from the same data, without errors creeping in between them, is where companies fall apart.

And if you're doing it on spreadsheets, you're going to fall apart faster.

The problem isn't compliance. It's reconciliation.

NGER and AASB S2 don't disagree with each other. They just want different things from the same underlying activity data. Understanding exactly where they diverge - and where the AASB has deliberately allowed alignment - is the difference between a two-person compliance operation and a five-person one.

Start with GWP values. NGER uses AR5 Global Warming Potentials as mandated by the National Greenhouse and Energy Reporting (Measurement) Determination 2008, updated in 2020. Methane gets a GWP of 28. Nitrous oxide gets 265. AASB S2, following the ISSB's IFRS S2, technically requires AR6 values from the latest IPCC assessment. Under AR6, methane comes in at 27.9 for non-fossil sources, and 29.8 for fossil-fugitive and process emissions. A small difference per tonne - but when you're aggregating across a corporate group with multiple facilities, those fractions compound.

Here's the relief valve. AASB S2025-1, issued December 2025, provides jurisdictional relief for NGER reporters. If you're required by the Clean Energy Regulator to report using AR5 GWP values, you can use those same values in your AASB S2 disclosure for the NGER-covered portion of your entity. You don't have to recalculate. But - and this matters - the relief only applies to the part of your business that NGER covers. Any emissions outside NGER scope (your Scope 3 categories, your non-reporting subsidiaries, any facilities below the 25 kt threshold that don't individually trigger NGER) still need to follow the GHG Protocol Corporate Standard and use AR6 values.

For a construction group with, say, eight NGER-registered facilities plus a dozen smaller project sites below threshold, that means you're running AR5 for part of your footprint and AR6 for the rest. In the same disclosure. If that sounds like it creates an internal reconciliation headache, it does.

Scope coverage is where the real gap opens up

NGER cares about Scope 1 and Scope 2. Energy consumed, energy produced, direct emissions from your facilities. That's it. For a construction company, that means the diesel your excavators burn, the electricity your site offices draw from the grid, the natural gas for any process heat, and fugitive emissions from refrigerants in your HVAC and cold rooms. Those are the numbers you submit through the EERS portal by 31 October.

AASB S2 wants all of that plus Scope 3. And for construction, Scope 3 is where the real emissions live.

Embodied carbon in concrete, steel, aluminium, and timber typically represents 70-90% of a construction project's total carbon footprint. A major commercial build might generate 2,000 tonnes of operational CO2-e over its construction phase but carry 40,000 tonnes in the materials alone. Under NGER, those material emissions don't exist in your report. Under AASB S2, they sit in Scope 3 Category 1 (Purchased Goods and Services) and you're expected to measure and disclose them from your second reporting period onward.

Then there's upstream transportation (Category 4), waste generated in operations (Category 5), business travel (Category 6), and employee commuting (Category 7). For a tier-one or tier-two builder running projects across multiple states with hundreds of subcontractors, each of those categories presents its own data collection challenge. And none of them appear anywhere in your NGER submission.

The practical effect: your NGER report covers maybe 10-30% of your total emissions profile. Your AASB S2 disclosure needs to cover the other 70-90% as well. Same compliance team. Same budget. Very different workload.

Construction makes the facility boundary problem worse

We've written about NGER facility definitions before, and it's worth revisiting because the facility boundary question is where NGER vs AASB S2 creates the most confusion for construction companies.

Under section 9 of the NGER Act, a facility is "an activity or series of activities that generate greenhouse gas emissions and produce or consume energy." A construction project site can absolutely be a single NGER facility if your company has operational control - meaning you set the operating, health and safety, and environmental policies. That 18-month road project with four excavators, a piling rig, two diesel generators, and 12 subcontractors? If you hold operational control, their fuel consumption is your emission to report.

Now apply that across a construction group operating concurrently in NSW, Queensland, Victoria, and Western Australia. You might have three or four project sites that individually exceed the 25 kt facility threshold, another eight that don't, and a corporate group aggregate well above 50 kt. Under NGER, you register and report at facility level. Each facility needs its own emission calculations, its own energy data, its own ANZSIC code classification.

Under AASB S2, the boundary works differently. You're disclosing at the entity level - the same reporting entity as your financial statements. Your organisational boundary follows either operational control or equity share (whichever your company applies for financial consolidation purposes). And you need to cover everything: every project, every subsidiary, every joint venture where you have operational control, across all scopes.

So you end up with a situation where your NGER facilities are a subset of your AASB S2 reporting boundary. The AASB S2 boundary is wider. It includes smaller sites, Scope 3 from your supply chain, and emissions from parts of the business that NGER never touches. If you've structured your data collection around NGER facility registrations only, you've got gaps.

We see this a lot. A construction company has a solid NGER process for its four registered facilities. Then AASB S2 arrives and suddenly they need emissions data from 15 additional project sites, their head office, their vehicle fleet that doesn't sit neatly under any single facility, and their concrete suppliers. The data collection infrastructure built for NGER doesn't scale to AASB S2 without deliberate expansion.

Deadlines that don't align

NGER has one deadline: 31 October, every year, no exceptions. It covers the financial year ending 30 June. The Clean Energy Regulator doesn't offer extensions. Late reporters get published on a list on the CER website. Penalties under section 19 of the NGER Act can reach $660,000 for failure to report.

AASB S2 reporting follows your financial year. For most Australian construction companies, that's a 30 June year-end with the annual report lodged by October. But AASB S2 disclosures need to go through your auditor - the same firm that signs off on your financial statements - and the assurance process adds time. Under ASSA 5010, limited assurance is required from Year 1 for Group 2 entities (reporting from FY starting 1 July 2026). Your auditor needs to review your governance disclosures, strategy sections, and Scope 1 and 2 emissions. If they're seeing your climate data for the first time in September, you're already behind.

The timing overlap is brutal. August and September become a crunch period where your team is simultaneously finalising NGER facility calculations for CER submission and preparing AASB S2 disclosures for auditor review. Both draw from the same underlying data. Both require documented evidence trails. But they're formatted differently, calculated (potentially) with different GWP values, and reviewed by different parties - the CER for NGER, your financial auditor for AASB S2.

If you're running this on parallel spreadsheets, August becomes the month where someone makes a transcription error that nobody catches until February. We're not being dramatic. The ANAO found that 72% of NGER reports it examined contained errors, and 17% had significant errors. That was in a single-framework environment. Add a second framework running concurrently off the same data, and the error surface area doubles.

What the data architecture actually needs to look like

Here's where we stop talking about the problem and start talking about the fix. You don't need two frameworks. You need one data layer that produces two outputs.

The underlying activity data - litres of diesel consumed, kWh of electricity purchased, kilograms of refrigerant topped up, tonnes of concrete delivered, kilometres driven - doesn't change between NGER and AASB S2. What changes is three things: the GWP values applied, the emission factors selected, and the scope boundary of what's included.

A properly structured carbon accounting system captures activity data once, at the source document level. Every fuel invoice, every electricity bill, every gas receipt gets ingested, classified, and linked to a project, a facility, and an organisational entity. From that single data layer, you can produce:

An NGER report that applies AR5 GWP values, covers Scope 1 and 2 only, is broken out by registered facility, classified by ANZSIC code, and formatted for the EERS electronic submission. This covers only the facilities where your corporate group meets NGER thresholds.

An AASB S2 disclosure that applies AR6 GWP values (or AR5 for the jurisdictionally-covered portion under AASB S2025-1 relief), covers Scope 1, 2, and 3, is presented at entity level consistent with your financial reporting boundary, and includes the qualitative elements - governance, strategy, risk management - alongside the quantitative metrics.

Same diesel invoice. Two different outputs. Zero manual reconciliation between them.

That's what we built Carbonly's report generation to do. You feed in your source documents - utility bills, fuel receipts, supplier invoices, whatever format they arrive in - and the system produces both NGER-compliant and AASB S2-compliant outputs from the same underlying dataset. The GWP conversion happens at the calculation layer, not in a cell formula that someone might accidentally overwrite.

The Scope 3 problem that NGER reporters aren't ready for

If you've been reporting under NGER for years, you're good at Scope 1 and 2. Your diesel numbers are tight. Your electricity consumption data is solid. Maybe you've even got a reasonable handle on refrigerant losses.

But AASB S2 demands Scope 3, and most NGER reporters have never seriously measured it. For construction companies, the Scope 3 categories that matter most are:

Category 1 - Purchased Goods and Services. This is where embodied carbon in materials sits. Concrete alone has emission factors ranging from 100 to 400+ kg CO2-e per cubic metre depending on the mix design. Steel runs around 1.5-2.5 tonnes CO2-e per tonne. If you're pouring 50,000 cubic metres of concrete on a single project, the Category 1 emissions from that material alone could exceed your entire Scope 1 footprint across all projects. But your concrete supplier might not have an EPD (Environmental Product Declaration), so you're stuck with generic factors and spend-based estimates that carry 30-40% uncertainty.

Category 4 - Upstream Transportation. Every truck delivering aggregate, concrete, steel, and timber to your sites generates emissions. For construction, transport distances can be significant - quarries aren't always close to project sites. And the data is hard to get because you're often buying "delivered to site" without visibility of transport emissions.

Category 5 - Waste. Construction and demolition waste in Australia exceeds 27 million tonnes annually. If your projects send waste to landfill, the methane generated over decades of decomposition is your Scope 3 emission to disclose.

The first-year Scope 3 exemption under ASRS gives you a one-year deferral. But that just means you need to be collecting the data now for next year's disclosure. We're not sure any construction company has truly nailed Scope 3 across hundreds of material types and dozens of suppliers yet - we won't pretend otherwise. But starting with your top 10 materials by spend and working outward is the only practical path. We've written about how to collect Scope 3 data from suppliers without getting ghosted.

Construction-specific data collection across both frameworks

A tier-two construction company running eight concurrent projects across three states might process 400+ utility documents per quarter. Electricity bills from temporary site connections. Diesel fuel invoices from three different suppliers. Gas bills for site offices. Waste transport manifests. Concrete delivery dockets. And that's before you count the fuel card transactions, the fleet telematics data, and the subcontractor reports.

Under NGER alone, you'd focus that data collection on your registered facilities. Maybe four of those eight projects are above threshold. You'd track diesel, electricity, gas, and refrigerants for those four, aggregate at facility level, and submit.

Under AASB S2, you need data from all eight projects. Plus head office. Plus the vehicle fleet. Plus your supply chain for Scope 3. Plus enough data to support your climate scenario analysis and transition plan disclosures.

The data collection problem isn't just volume. It's that construction sites generate messy, inconsistent documents. A diesel delivery docket from a regional supplier looks nothing like a fuel card statement from a national fleet provider. An electricity bill for a temporary construction power connection might list the site address differently from your NGER facility registration. Concrete delivery receipts come in every format imaginable - some have mix codes, some don't, some list cubic metres, others list tonnes.

We built Carbonly's document processing to handle that variation. It reads utility bills, fuel receipts, delivery dockets, and supplier invoices in whatever format they arrive - PDF, scanned image, CSV, Excel - and extracts the activity data regardless of layout. The extraction links every data point back to the source document, so when your NGER auditor or your financial auditor asks "where did this number come from?", the answer is a direct link to the invoice. Not a reference to cell D47 in a spreadsheet that someone might have edited since.

The audit trail problem nobody talks about

NGER and AASB S2 have different assurance requirements, delivered by different parties.

For NGER, the Clean Energy Regulator runs a targeted audit program. They might select you for a re-audit based on their risk analysis. If they do, you need to produce records going back five years. The audit follows ASAE 3000 (Assurance Engagements Other than Audits or Reviews).

For AASB S2, your financial auditor performs the sustainability assurance engagement under ASSA 5000/5010. They're looking at your data through a different lens - financial materiality, internal controls, consistency with your financial statements. And they can't be a separate firm from your financial auditor; the Corporations Act requires the same auditor to handle both.

Both audits need an evidence trail from the reported number back to the source document. But the way you present that trail differs. NGER wants facility-level drill-down by gas type. AASB S2 wants entity-level disclosure with methodology documentation, a Basis of Preparation statement, and governance evidence.

If your audit trail lives in spreadsheets, you're maintaining two parallel evidence chains. Every time someone updates a number in one, they need to update it in the other. Every time a source document gets reclassified, both models need to reflect it. This is where the errors creep in - not in the original data entry, but in the synchronisation between two versions of the same underlying truth.

A single-platform approach eliminates this. One audit trail, one source of truth, two report outputs. That's not a nice-to-have. For construction companies with multi-state operations and hundreds of source documents, it's the only way to run dual frameworks without hiring a second compliance team.

Start with the data, not the framework

If you're a construction company currently reporting under NGER and preparing for your first AASB S2 disclosure, don't start by reading the standard cover to cover. Start with your data.

Map every source of activity data across your business - not just the NGER-registered facilities, but every project site, every vehicle, every supplier that sends you an invoice. Figure out where your documents live (email inboxes, shared drives, supplier portals, fuel card platforms) and how you'll get them into one place. That data map is the foundation for both frameworks.

Then build the calculation layer once. Use AR5 for NGER-covered portions, AR6 for everything else (or all AR5 under the AASB S2025-1 jurisdictional relief where it applies). Apply NGA emission factors for NGER, and supplement with supplier-specific factors, EPDs, and spend-based proxies for Scope 3 under AASB S2.

The frameworks are different. The data isn't. Get the data right once, and both reports become outputs rather than projects.

Carbonly produces both NGER and AASB S2 compliant reports from a single dataset. If you're staring at two spreadsheets right now, wondering which one has the right version of your Q3 diesel numbers - that's the problem we built this to fix.

NGER vs AASB S2: Running Dual Frameworks Without Doubling Your Team