Scope 1 and Scope 2 get used loosely in a lot of sustainability conversations, but the distinction is specific and it matters for how a project gets reported. Scope 1 covers direct emissions from sources a company owns or controls, fuel burned in an on-site boiler, a fleet vehicle, a gas-fired furnace. Scope 2 covers indirect emissions from purchased energy, electricity, steam, heat, or cooling bought from someone else and consumed on site. The emissions physically happen at the power station, not the factory, but they're counted against the site because the site's demand is what caused them.
Where compressed air actually sits
An electrically driven rotary screw compressor, which describes the overwhelming majority of compressed air plant in Australian manufacturing, runs entirely on purchased grid electricity. Reducing the load on that compressor, by fixing leaks, running fewer loaded hours, or improving control strategy, reduces the kilowatt-hours drawn from the grid. That's a Scope 2 reduction, not a Scope 1 one, because nothing about a leak repair changes any on-site fuel combustion.
The exception is a site running a diesel or gas-driven compressor directly, without going through the electricity grid at all. That's uncommon in general manufacturing, most sites use electric compressors, but it's worth checking rather than assuming, since it changes which scope the saving gets reported against. It's also worth checking whether a site runs a mixed fleet, a large electric base-load compressor with a smaller diesel unit for backup or peak demand, since in that case the scope split depends on which machine is actually carrying the load a given leak is drawing from.
None of this changes the underlying physics of the leak itself. A hole in a pipe wastes the same compressed air whether the compressor behind it burns diesel or draws from the grid. What changes is purely the accounting, which scope line the saved energy gets attributed to, and that's worth getting right before a number goes into a report someone else will scrutinise.
| Scope | Covers | Where compressed air fits |
|---|---|---|
| Scope 1 | Direct emissions, owned/controlled sources | Only if compressor is diesel/gas-driven on site |
| Scope 2 | Indirect emissions, purchased electricity | Applies to almost all electrically driven compressors |
A leak doesn't burn fuel on site. It burns purchased electricity, which makes the fix a Scope 2 lever.
Location-based versus market-based, and why it matters here
The GHG Protocol requires Scope 2 emissions to be reported two ways. The location-based method uses the average emissions intensity of the electricity grid where a facility sits, it reflects the physical reality of what was drawn from the grid. The market-based method instead reflects purchasing decisions, renewable energy certificates or power purchase agreements a company holds, subtracted from its load before the remaining consumption is multiplied by a residual grid factor.
A leak repair reduces physical electricity draw, so it shows up cleanly in the location-based figure regardless of anything else. Under market-based accounting, the picture depends on what's already been contracted: a site that's purchased renewable certificates covering its full load may show a very low market-based Scope 2 figure already, in which case a leak fix mainly reduces how much renewable supply is needed to keep covering that load, rather than moving the reported number further. Either way, the physical reduction is real. Which figure it moves, and by how much, depends on what accounting method and procurement position a company is reporting against.
Who this actually matters for in Australia
Large emitters have a formal obligation here: under the National Greenhouse and Energy Reporting scheme, a facility emitting 25,000 tonnes CO2-e or more, or a corporate group above 50,000 tonnes CO2-e, must register and report annually to the Clean Energy Regulator. Most individual manufacturing sites sit well below that threshold on their own. But a site doesn't need to be an NGER-reportable entity itself to have this matter: sites supplying into a larger corporate group's emissions inventory, or reporting voluntarily as part of a customer's supply-chain sustainability requirements, are increasingly being asked for exactly this kind of measured, defensible energy figure, not a modelled industry-average estimate.
Why this is a genuinely reportable reduction
A lot of efficiency claims are hard to quantify cleanly for a sustainability report, the savings are indirect, or bundled with other changes, or estimated with wide error bars. A leak fix is comparatively clean: a measured CFM figure converts directly into kilowatt-hours through the compressor's efficiency, and kilowatt-hours convert directly into an emissions figure using the relevant electricity grid emissions factor. See what compressed air leaks actually cost in Australia for how the CFM-to-dollar conversion works, the same arithmetic applies to CFM-to-kWh, which is the number a Scope 2 calculation actually needs.
That clean conversion is worth contrasting with how a lot of "soft" efficiency initiatives get reported, staff behaviour campaigns, general awareness programs, and similar measures that are genuinely valuable but notoriously hard to attribute a specific, defensible number to. A leak fix skips that problem entirely: the before-and-after CFM figures are measured, not inferred from a survey of staff attitudes or an assumption about compliance rates.
What it takes to make the number defensible
The reduction is only as credible as the measurement behind it. A modelled or estimated leak size produces a modelled, estimated emissions reduction, which is a weaker claim in a sustainability report than a measured one. A repeatable methodology, the same acoustic survey approach applied consistently, run before and after a repair round, gives a before-and-after CFM figure that supports an actual reported reduction rather than a directional estimate.
That's also why a single audit is a weaker basis for ongoing emissions reporting than a repeated measurement cycle. One number shows what leak load existed on the day of the survey. A tracked series, the same measurement basis repeated over time through ongoing monitoring, shows whether the Scope 2 reduction is actually holding, since leak load left unmanaged drifts back up between visits. See how the measurement itself works for what that repeatability is actually built on.
Intensity metrics, not just absolute totals
Many sustainability reports track emissions intensity, tonnes of CO2-e per unit of output, rather than a raw total, since output naturally varies year to year. Leak load has an awkward relationship with that metric: a compressor drawing power to feed a leak is consuming electricity that contributes nothing to output at all, which means unmanaged leak load quietly inflates emissions intensity independent of anything happening on the production line. Closing that gap improves the intensity figure without needing production to change, which is a cleaner story for a sustainability report than most efficiency measures can offer, since it isn't confounded by output volume moving around for unrelated reasons.