If you’re a finance director at a business coming into ASRS, you’ll be asked for your emissions numbers. The request usually turns up as one line in a board pack or a lender’s questionnaire. The challenge is that almost none of those numbers live in your finance system, and you’ll be the one signing off on figures pulled from systems you don’t own.
That’s why Acumentis ESG starts every baseline by mapping where the data sits. This article covers where your Scope 1, 2 and 3 data comes from, which emission factors to use, and how to build a first baseline that holds up. If you’re still working out whether your business has to report at all, start with our guide to ESG reporting.
Key takeaways
- Carbon accounting can struggle to find the data, but not to calculate it. Most of your Scope 1 and 2 numbers already exist, held by fleet and facilities rather than finance.
- Check Scope 3’s fifteen categories for what is material instead of measuring all of them. A small number usually carry most of the footprint.
- Australian businesses convert activity data using the National Greenhouse Accounts Factors. State which year’s factors you used and stay consistent across the period.
What is carbon accounting?
Carbon accounting (also called GHG accounting) is measuring the greenhouse gases your business is responsible for and turning them into one comparable number.
Almost everyone uses the same method, the Greenhouse Gas Protocol. It sorts your emissions into three groups based on how much control you have over them:
- Scope 1 covers emissions from things you own or control.
- Scope 2 covers the energy you buy.
- Scope 3 covers everything else in your value chain.
The outcome is that the data for each group lives somewhere different. That’s the part a lot of guides and articles skip, and it’s where first-time reporters can lose months.
Is this the same as ASRS reporting?
No. Carbon accounting produces the numbers. ASRS reporting is the disclosure they go into. You can’t do the second without the first, which is why baselines usually start a year before the report is due.
| Scope | Where the data lives | Who usually owns it | Common blocker |
|---|---|---|---|
| Scope 1 | Fuel cards, gas bills, refrigerant service records | Fleet, facilities | Records kept locally, never consolidated |
| Scope 2 | Electricity bills and meter data | Facilities, procurement | Several sites and retailers, no single register |
| Scope 3 | Supplier, tenant and freight records | Procurement, plus other businesses | The data belongs to someone else |
Where does your Scope 1 data come from?
Your own fuel and equipment. This is the most straightforward of the three, which is a good reason to start here.
Look for:
- Fuel card statements for vehicles and plant
- Gas bills for heating and process use
- Service records for refrigerants and air conditioning
- Fuel logs for any on-site generation
The data almost always exists. Fleets hold some of it, facilities hold the rest, it’s just that nobody has been asked to put the two together before.
Where does your Scope 2 data come from?
Your electricity retailer. Bills and meter data give you the consumption figures, and a published factor turns those into emissions.
There are two ways to calculate it.
- The location-based method uses the average emissions of the grid you draw from.
- The market-based method uses what you’ve contracted to buy, such as a green power agreement. AASB S2 asks for the location-based figure.
Collecting the bills is usually easy. Consolidating them is more difficult. A business with fifteen sites can have several retailers, different billing cycles and no single register of which meter belongs where. If you manage a property portfolio, that reconciliation is usually the longest job in the whole baseline.
Where does your Scope 3 data come from?
Mostly from other people. That’s what makes it hard, and it’s why it tends to get left until last.
The Greenhouse Gas Protocol defines fifteen categories of Scope 3, covering purchased goods, freight, business travel, waste, leased assets and more. Trying to measure all fifteen in your first year is a common pitfall.
So, screen them instead. Work out which categories are likely to be material for your business, usually a small number carrying most of the footprint, and build those properly. First reporters get transition relief on Scope 3, so there’s room to do this in stages.
Your own systems hold more than you’d expect: travel bookings, accounts payable, waste contractor reports. The rest comes from suppliers, which is why your larger customers have started asking you for the same thing.
What if a supplier won’t give me the data?
Estimate it. Published factors and spend-based methods will get you a defensible number, as long as you disclose the basis you used. One uncooperative supplier shouldn’t hold up an entire baseline.
Which emission factors do Australian businesses use?
The National Greenhouse Accounts Factors are published each year by the federal government.
Activity data on its own isn’t an emissions number. Ten thousand litres of diesel becomes a tonnage figure only once you apply a factor to it. The NGA Factors are the Australian set, covering fuels, electricity by state, and waste.
Three things to get right:
- State which year’s factors you used
- Use the same vintage across a whole reporting period
- Keep a copy of the workbook you worked from
Get the vintage right and your figures stay comparable year on year, which is most of what makes a baseline useful.
How do you build a first carbon accounting baseline?
Set your boundary first. Decide which entities, sites and assets sit inside it, because everything downstream depends on that answer.
Then work in this order:
- Collect the data that already exists
- Estimate what doesn’t, and write down how you estimated it
- Apply the right emission factors
- Record your assumptions as you make them
- Set out how you’ll improve the number next year
Year one is about structure, transparency and a plan to improve. Australia’s first reporters found the same thing. A documented, imperfect baseline beats a precise number nobody can trace, and it’s what every year of carbon reporting after this one builds on.
Where to start with carbon accounting
Map where your Scope 1 and Scope 2 data sits and who holds it, before you go near Scope 3. Most of the delay in a first carbon accounting exercise comes from finding data rather than calculating it.
Once you know which system holds each number and who owns it, the rest is process. Emissions reporting gets easier every year after the first, because the map doesn’t change much.
If you’d like the method as well as the map, Episode 6 of our on-demand modules walks through a six-step baseline and a worked client example in under twelve minutes. Then, our climate and compliance advisory team can run the boundary and baseline work alongside you.
Frequently Asked Questions
Carbon accounting measures what you emit. Offsetting is buying credits to compensate for some of it. You need the first before the second means anything, because you can’t offset a number you haven’t measured.
Not directly, unless you meet the ASRS group thresholds. Many smaller businesses end up doing it anyway, because a larger customer needs their supply chain data or a lender asks at renewal.
Disclosed assumptions and a visible method protect you far better than a precise-looking figure with no working behind it. Restating a number you documented is manageable, while defending one you can’t trace is not.
It will store your data and run the calculations, which saves real time. It won’t set your boundary, decide which Scope 3 categories are material, or create source evidence that doesn’t exist yet.
References
Greenhouse Gas Protocol: Corporate Accounting and Reporting Standard
