Appendix 6: Emissions inventory
Our emissions inventory complies with the ISO 14064-1:2018 standard and reflects a financial control consolidation approach to determine the scope of our emissions reporting. This means that we have included only the organisations and assets that we have financial control of within Categories 1 and 2. Other emissions outside of our organisational boundary are reported in Categories 3 to 6.
Changes to emission factors and additional sources
This is the third year that we have completed a greenhouse gas emissions inventory, with emissions measured in 2018/19 (our baseline year), 2022/23, and 2023/24. The baseline year was chosen as a pre-pandemic year to provide a more consistent point of comparison, as emissions reduced during the pandemic.
Since 2022/23, we have been measuring three additional emissions sources: emissions from staff commuting, emissions from staff working from home, and recycling emissions. The baseline year was not restated for these new sources – we cannot conduct accurate retrospective staff surveys for commuting and working from home, and the recycling emissions were considered immaterial because they were less than 0.5% of our total emissions.
An additional source for this year was emissions data from our external audit service providers. This was a small pilot using data collected from three external providers. The results were not extrapolated because each provider works on a different number of audit clients, and because these clients vary in size and complexity we do not have an accurate method for extrapolation. Overall, the data from this pilot added 4.3 tCO₂e to our inventory (0.4% of total 2023/24 emissions), all in Category 3. The pilot will be rolled out to all external audit service providers in 2024/25 so that we can collect more complete emissions data. Prior years have not been restated to include this source because the data cannot be gathered retrospectively.
Toitū Envirocare sources its emissions factors primarily from the Ministry for the Environment, and updates the factors annually based on new underlying data. These updated emission factors have been applied to our 2023/24 emission sources. Prior years have not been restated with these updated factors because the impact is less than 5% of the total emissions.
We will continue to review our systems and data sources to provide a more complete carbon footprint over time.
Inventory summary
Our emissions for 2023/24 are set out in the table below, based on the sources we are currently able to measure. The increase in Category 3 emissions is largely from including the new emissions sources for staff commuting and working from home. The additional data source from the external service providers pilot added only an additional 4.3 tCO₂e to Category 3 emissions.
| Category (ISO 14064-1:2018) tCO₂e | Scopes (ISO 14064-1:2006) | 2018/19 tCO₂e | 2022/23 tCO₂e | 2023/24 tCO₂e | Movement 2022/23 to 2023/24 |
|---|---|---|---|---|---|
| Category 1: Direct emissions and removals | Scope 1 | 104 | 100 | 102 | 2 |
| Category 2: Indirect emissions from imported energy | Scope 2 | 47 | 29 | 38 | 9 |
| Category 3: Indirect emissions from transportation | Scope 3 | 663 | 1,095 | 1,031 | (64) |
| Category 4: Indirect emissions from products used by organisation | Scope 3 | 44 | 44 | 48 | 4 |
| Category 5: Indirect emissions associated with the use of products from the organisation | Scope 3 | 0 | 0 | 0 | 0 |
| Category 6: Indirect emissions from other sources | Scope 3 | 0 | 0 | 0 | 0 |
| Total direct emissions | 104 | 100 | 102 | 2 | |
| Total indirect emissions | 754 | 1,168 | 1,117 | (51) | |
| Total gross and net emissions | 858 | 1,268 | 1,219 | (49) |
Note: tCO₂e stands for tonnes of carbon dioxide equivalent.
Category 1 emissions relate to fuel consumption from our vehicle fleet. These have remained steady year-on-year and remain one of our largest sources of emissions.
Category 2 emissions are from our electricity use, and dropped in 2022/23 due to a change in emissions factors. This is not representative of our actual electricity usage in kiloWatts, which has increased each year. In 2023/24, our electricity use was higher than in previous years, despite the calculated emissions being lower.
Category 3 emissions have decreased by 64 tCO₂e in 2023/24 compared to last year. Air travel emissions from international relocations have decreased by 238 tCO₂e, which reflects our reduced reliance on overseas audit staff. Staff commuting emissions have increased by 168 tCO₂e. The underlying data from our staff commuting is highly uncertain, as it is an extrapolation of surveys run during the year.
Category 4 emissions increased by 4 tCO₂e in 2023/24, largely due to emissions from wastewater. This emissions source is based on the staff commuting survey mentioned above so the underlying data carries a high level of uncertainty.
Inherent uncertainty
We calculated our emissions based on supplier sources and the most up-to-date emission factors available from Toitū Envirocare at the time our inventory was produced and independently verified. However, there is inherent uncertainty in preparing a greenhouse gas emissions inventory due to estimations and extrapolation, as well as uncertainty related to the emissions factors.
Where possible, we have collected source data directly from suppliers. For some, we had to estimate or extrapolate information (such as emissions from our vehicle fleet and staff commuting), which increases the level of uncertainty.
There is also a degree of uncertainty with the emissions factors provided by Toitū Envirocare. For example, as vehicles become more efficient over time, the emissions for each kilometre travelled reduces. The electricity emissions factor tends to move more than other factors because in some years there is more thermal generation and in other years more renewable generation.