This greenhouse gas emissions report inventories Aarhus University’s direct and indirect CO2e emissions1 in 2024, calculated in compliance with the GHD protocol. The report is prefaced by a review of the methodology used to measure AU’s emissions. Then the results for 2024 are presented.
In 2024, Aarhus University emitted 23,476 tonnes of CO2 within the baseline emission categories. This corresponds to a decrease of 11 per cent over 2023 and a decrease of 35 per cent over the 2018 baseline.
The decrease since 2018 is mainly due to a reduction in the use of oil and gas for heating, fewer flights and external factors such as a greener energy mix from electricity. This development should be seen in the light of the fact that Aarhus University saw growth in FTEs of approximately 11 per cent in the same period. This means that CO2 emissions per employee fell from 4.6 tonnes C02 in 2018 to 2.7 tonnes in 2024 – a reduction of approximately 42 per cent.
For historical reasons, energy-related activities (scope 3.3), waste (scope 3.5) and investments (scope 3.15) are not included in the baseline emission categories. The university’s total emissions in these emission categories amounted to 1,623 tonnes of CO2.
Finally, in 2024, Aarhus University emitted 61,986 tonnes of CO2 within scopes 3.1 and 3.2, which cover the purchase of goods, services and capital goods. Emissions in these categories were calculated using a financial accounting method.
The greenhouse gas emissions report concludes with a list of retrospective changes to previous reports. These changes include corrections of isolated errors and updates to emission factors. The greenhouse gas emissions report for 2023 was recalculated in this connection, and now shows a 1.3 per cent increase in CO2 emissions over 2022.
Below is a review of the methodological framework and the methods used by Aarhus University to report emissions in this greenhouse gas emissions report.
Aarhus University’s greenhouse gas emissions report was prepared using the GHG protocol.
The GHG protocol divides the emissions attributable to an organisation into three different scopes, i.e. three difference sources of CO2 emissions:
To calculate Aarhus University’s CO2 emissions, two main methods were used: the activity-based method and the financial data-based method. Here is why multiple methods have been used.
Aarhus University’s first greenhouse gas emissions report was for 2018. This report is the baseline for calculating subsequent developments in the university’s CO2 emissions and in relation to the university’s climate targets. When the 2018 report was prepared, it was possible to collect relatively reliable CO2 data for emissions within scope 1, scope 2 and for air travel and water (scope 3). This data was calculated using the activity-based method (see more below).
The university’s CO2 emission reduction targets were set based on the categories of emissions it was possible to measure at the time. These constitute the ‘baseline emission categories’ and include:
Since 2020, more sources of emissions have been added to the greenhouse gas emissions report, which enables a larger proportion of the university’s total emissions to be calculated and included in the report. Specifically, the following sources of CO2 emissions have been added.
Here is a more detailed breakdown of both methods, including their applications and limitations. All of the methods used also comply with a methodological framework developed by the green house gas reporting group under Universities Denmark.
The activity-based method is used in the greenhouse gas emissions report to calculate CO2 emissions. The calculations are based on concrete data for emissions from different sources, for example consumption of energy and fuel and travel activity. Unlike the financial data-based method (described below), which bases calculations on expenditure in Danish kroner, the activity-based method bases calculations on physical units of measurement – such as kWh, litre or kilometre – which are multiplied by specific emission factors.
The emission factors are typically sourced from national or international databases, such as the Danish Energy Agency’s standard factors or DEFRA (UK). These factors take the type of activity and energy source into account. For example, district heating consumption is multiplied by an emission factor that reflects the heating plant’s energy mix and efficiency.
In addition, the method uses some emission factors developed by Aarhus University’s own researchers. These factors are also used in the national carbon emission inventories.
This method makes more precise and direct calculations of emissions possible when detailed data on consumption is available. It is particularly suitable for calculating scope 1 and 2 emissions (such as direct emissions from petrol consumption and energy purchases). It can also be used for selected categories in scope 3 for which activity data are available.
One limitation of the activity-based method is that it relies on detailed, accurate data reporting for each activity, which is not always possible.
Since Aarhus University first began preparing greenhouse gas emissions reports, there have been improvements in how CO3 emissions are calculated. This has made it possible to include emissions from a wider range of activities in the university’s emission inventory. An important contributor to this development has been the introduction of the financial data-based method, which was used in for the first time in AU’s greenhouse gas emissions report for 2020.
The financial data-based method is used to calculate scopes 3.1 and 3.2, which cover emissions from the purchase of goods, services and capital goods.
To link data on consumption with emission factors, the method uses classifications that correspond to the categories of goods and services used in AU’s financial accounting – such as standardised product codes in the UNSPCS (United Nations Standard Products and Services Code). This makes it possible to assign relevant emission factors to specific categories of goods and services for which it would otherwise be impossible to calculate CO2 emissions at this point in time.
The method provides a broad, holistic picture of the organisation’s climate footprint. However, it also has certain limitations:
However, the method is becoming continually more refined and accurate as more product categories are added, and because emission factors are gradually being developed for more specific subcategories.
When preparing the greenhouse gas emissions report for 2023, Aarhus University used a new tool from a private IT supplier. Using artificial intelligence and machine learning, this tool does a better job of matching the university’s expenditure with the appropriate emission factors. As a result, more of AU’s financial activities can be included in the greenhouse gas emissions report. In addition, the supplier is also starting to include product-specific emission factors from selected suppliers in the tool, which will make it possible to prepare a more detailed greenhouse gas emissions report in future.
With this approach to continued methodological development, it is to be expected that it will be necessary to revise reports from previous years based on new knowledge. This is a natural consequence of working with an area in which advances are constantly being made.
An inventory of Aarhus University’s CO2 emissions in 2024 is presented below. The results for the baseline emission categories are presented first.
The results for fuel and energy-related activities (scope 3.3), waste (scope 3.5) and investments (scope 3.15) follow. Results for these categories, as for the baseline emission categories, have been calculated using the activity-based method. However, they cannot be compared with the baseline, as no data from 2018 is available.
The report concludes with the results for scope 3.1 and 3.2, which cover emissions from the purchase of goods and services (3.1) and capital goods (3.2). These results were calculated using the financial data-based method.
Table 1 provides an overview of CO2 emissions in 2024 within the baseline emission categories. Aarhus University emitted 23,476 tonnes of CO2 within the baseline emission categories. This corresponds to a decrease of 11 per cent over 2023 and 35 per cent over 20182.
Table 2 provides an overview of CO2 emissions per employee within the baseline emission categories. Compared to 2023, emissions were reduced by 13 per cent per employee and 42 per cent per employee over the 2018 baseline. This reduction should be seen in the context of the fact that the university saw growth in the number of full-time equivalents of approximately 11 per cent in the same period.
Below is a more detailed description of the development within the various categories.
Table 1: Aarhus University's CO2 emissions in 2024 for the baseline emission categories
| Scopes | Category | Tonnes CO2 |
|---|---|---|
| Scope 1 | On-site heating (oil and gas) | 590 |
| Transportation | 1,145 | |
| Agriculture | 3,647 | |
| Scope 2 | District heating | 2,337 |
| Electricity | 4,390 | |
| Scope 3 | Water & wastewater | 2,104 |
| Air Travel | 9,263 | |
| Total | 23,476 |
Table 2: Aarhus University's CO2 emissions per employee in 2018 to 2024 (FTE)
| Description | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 |
|---|---|---|---|---|---|---|---|
| CO2 emissions per employee (FTE) | 4.6 | 3.8 | 2.2 | 2.3 | 3.1 | 3.1 | 2.7 |
| Development in per cent over 2018 | -17 % | - 52 % | - 51 % | - 33 % | - 33 % | - 42 % |
Within Scope 1, the categories ‘Transportation’, ‘On-site heating’ and ‘Agriculture’ hae developed as follows.
Transportation:
In 2024, Aarhus University emitted 1,145 tonnes of CO2 in the category ‘Transportation’, which covers emissions from Aarhus University’s cars, service vehicles, the research vessel Aurora and work-related driving in employees’ own cars. This corresponds to an increase of 2 per cent over 2023 and 25 per cent over 2018. The major factor accounting for the increase over 2023 is greater activity on the part of AU’s research vessel Aurora. The increase over 2018 is primarily due to the fact that beginning wit the 2020 greenhouse gas emissions report, Aarhus University began including consumption of petrol and diesel from vehicles like tractors in the category ‘Transportation’. This means that the figures from 2018 and 2024 are not fully comparable.
On-site heating:
Aarhus University emitted 590 tonnes of CO2 in 2024 within the category ‘Heating on the premises’, which covers the consumption of fuel oil and gas. This corresponds to decrease of 5 per cent over 2023 and 65 per cent over 2018. The major factor accounting for this development is that AU is phasing oil furnaces and reducing gas consumption.
Agriculture:
Aarhus University’s agricultural activities emitted 3,647 tonnes of CO2. This corresponds to a decrease of 9 per cent over 2023 and 23 per cent over 2018. The factors behind this development include a reduction in emissions from dairy cattle and manure management for both dairy cattle and swine.
Scope 2
Within Scope 2, the categories ‘District heating’ and ‘Electricity’ have developed as follows.
District heating:
Aarhus University’s C2 emissions from the consumption of district heating amounted to 2,337 tonnes CO2. This corresponds to a decrease of 51 per cent over 2023 and an increase of 5 per cent over 2018. The decrease over 2023 is primarily due to a significantly lower emission factor for district heating from Kredsløb in Aarhus. The reason for this was that 2023 was an exceptional year: as a result of a big fire in Kredsløb’s silo of wood pellets, the heating plant burned more coal than usual. The increase of 5 per cent over 2018 is particularly due to a change in the fuel mix in the district heating supplied by the district heating plants that supply district heating to Aarhus. In the same period, Aarhus University reduced consumption of district heating by 9 per cent.
Electricity:
Aarhus University’s CO2 emissions from the consumption of electricity amounted to 4,390 tonnes CO2. This corresponds to a decrease of 2 per cent over 2023 and a decrease of 56 per cent over 2018. This development is primarily due to the fact that the Danish energy mix has become more sustainable through the expansion of solar and wind energy, while the university has also reduced its power consumption by 13 per cent since 2018.
Within Scope 3, the categories ‘Water and wastewater’ and ‘Air travel’ have developed as follows.
Water and wastewater:
Aarhus University’s C2 emissions from water and wastewater amounted to 2,104 tonnes CO2. This corresponds to decrease of 16 per cent over 2023 and 48 per cent over 2018. The development can be attributed in particular to a significant reduction in the consumption of water.
Air travel:
Aarhus University’s CO2 emissions from air travel amounted to 9,263 tonnes CO2. This corresponds to an increase of 4 per cent over 2023 and a decrease of 27 per cent over 2018.
Table 3 provides an overview of CO2 emissions from fuel and energy-related activities (scope 3.3), waste (scope 3.5) and investments (scope 3.15). As stated in the methodology section, no data for these categories is available dating back to 2018, and they are therefore not included in the baseline emissions categories.
| Category | Tonnes CO2 |
|---|---|
| Fuel and energy-related activities (scope 3.3) | 338 |
| Waste (scope 3.5) | 10 |
| Investments (scope 3.15) | 715 |
Fuel and energy-related activities (scope 3.3):
Table 2 shows that Aarhus University emitted 338 tonnes of CO2 from fuel and energy-related activities, which represents an increase of 7 per cent over 2023. This category includes emissions associated with the production and transportation of fuel used by Aarhus University which is not included in scope 1. This includes things like emissions from the extraction, refinement and transportation of fuel.
Waste (scope 3.5):
Table 2 shows that Aarhus University emitted 10 tonnes of CO2 from waste, which is a decrease of 70 per cent over 2023. This development is primarily explained by lower emission factors for waste.
Investments (scope 3.15):
Table 2 shows that Aarhus University’s investments emitted 715 tonnes of CO2. Cf. section 4 below, this development cannot be meaningfully compared with 2023, as CO2 data was available for a significantly larger proportion of Aarhus University’s portfolio of shares in 2024 than previously. This is because the university has switched to a new asset manager which provides more comprehensive climate data.
Table 4 shows that in 2024, Aarhus University emitted 55,878 tonnes of CO2 from the purchase of goods and services (scope 3.1) and 6,108 tonnes of CO2 from purchases of capital goods (scope 3.2).
Table 4: Aarhus Universitets CO2-udedning i 2024 fra varer, tjenesteydelser og kapitalvarer
| Scope | Tonnes CO2 |
|---|---|
| Goods and services (scope 3.1) | 55,878 |
| Capital goods (scope 3.2) | 6,108 |
| Total | 61,986 |
The five largest categories (UNSPSC codes) of CO2 emissions in scope 3.1. are as follows:
The five largest categories (UNSPSC codes) of CO2 emissions in scope 3.2 are as follows:
1. Corrected calculation of CO2 emissions from oil in the greenhouse gas emissions report for 2023
In the greenhouse gas emissions report for 2023, the CO2 emissions for oil were calculated incorrectly. The error concerned the overall category ‘on-site heating’ and affected the inventory for 2023 as well as comparisons with 2018 and 2022. The error has now been corrected for all three years.
2. Updated emission factors for water and wastewater (2018-2023)
In this year’s greenhouse gas emissions report, AU used updated emission factors for water and wastewater that will be used going forward. These factors have also been used to recalculate reports back to 2018, which provides a more accurate CO2 emission inventory for these years. The updated emission figures for 2018-2023 are shown in table 5.
Table 5: Overview of CO2 emissions from water and wastewater 2018-2023
| 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | |
|---|---|---|---|---|---|---|
| Water (Tonnes CO2) | 324 | 245 | 210 | 199 | 218 | 202 |
| Wastewater (Tonnes CO2) | 3,704 | 2,804 | 2,402 | 2,275 | 2,494 | 2,308 |
3. Updated emission factors for agriculture (2018-2023)
The national emission inventories for agriculture have been updated for 2024 and retrospectively, including with regard to emissions from indirect nitrous oxide and methane from cattle and swine. In order to align with these updated emission inventories, Aarhus University's CO2 emissions from agriculture have also been updated for 2018-2023, and the updated emission factors were also used in the calculation of the 2024 greenhouse gas emissions report. The updated emission figures for 2018-2023 are shown in table 6.
Table 6: Overview of CO2 emissions from water and wastewater 2018-2023
| 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | |
|---|---|---|---|---|---|---|
Agriculture (Tonnes CO2) | 4,743 | 4,744 | 4,059 | 4,365 | 3,999 | 4,023 |
4. Updated input for air travel in 2023
One of the input parameters (number of km flown) for calculating CO2 emissions for aircraft has been updated with new information. This has resulted in an upward adjustment of CO2 emissions from air travel in 2023 to 8,864 tonnes CO2.
5. Missing transport data in the greenhouse gas emissions report for 2023.
During the preparation of the climate accounts for 2024, it was discovered that AU had not received complete data on the purchase of petrol for the 2023 report. The correct figure was not known at the time of publication for the 2023 but has now been updated. The correct figure for CO2 emissions for transportation in 2023 is 1,124 tonnes of CO2.
6. Update in 2023 for purchases of goods, services and capital goods (scope 3.1 and 3.2)
The external supplier that handles Aarhus University’s CO2 inventories for scope 3.1 (goods and services) and scope 3.2 (capital goods) has updated the emission factors used in their model. The new model is based on a new version of Exiobase (an emissions factor database) with more detailed data. The update applies retroactively, and thus applies to AU’s 2023 inventory as well. This has resulted in the following adjustment in CO2 emissions for scope 3.1 and 3.2 for 2023 (Table 7):
Table 7: Update of CO2 emissions from scope 3.1 and scope 3.2 in 2023
| Scope | Tonnes CO2 |
|---|---|
| Goods and services (scope 3.1) | 56,483 |
| Capital goods (scope 3.2) | 5,937 |
7. Typo in figure in the greenhouse gas emissions report for 2023
As a result of a typo, there were incorrect figures in the figure ‘Total process and spend based emissions 2023” for
transportation, water, waste and air travel. The error did not affect the accuracy of the calculations.
Cf. subsections 2, 4 and 6 above, CO2 emission figures for these categories in 2023 have also since been updated.
8. Update of CO2 emissions from the production and transportation of fuel as well as energy-related activities (scope 3.3) for 2023
The figures for emissions from the production and transportation of fuel and energy-related activities (scope 3.3) from 2024 also include CO2 emissions from the production and transportation of petrol from non-road mobile machinery (such as tractors). These categories have been recalculated for 2023. The updated inventory for total CO2 emissions in scope 3.3 in 2023 is 317 tonnes.
9. The total effect of corrections to the greenhouse gas emissions report for 2023 in the baseline emission categories
Based on the above corrections, CO2 emissions in 2023 for the baseline emission categories amounted to 26,343 tonnes, which corresponds to an increase of 1.3 per cent over 2022 and an overall decrease of 27 per cent over 2018.
10. CO2 emissions by municipality for electricity from 2024
Energinet provides the emission factor for electricity. Previously, Energinet used one national emission factor, but since 2024, Energinet has used municipality-specific emission factors, as there are local differences in the energy mix. In the greenhouse gas emissions report for 2024, these municipality-specific emission factors are used which are not directly comparable to the national emission factors used in previous years. However, the differences are estimated to be so small that it is still possible to compare CO2 emissions from 2024 with previous years.
11. Extended coverage of AU's investments from equities is included in the climate accounts for 2024
Previously, only one of the three asset managers used by AU was able to provide data on CO2 emissions from equity investments. In 2024, Aarhus University switched to a new asset manager that manages the entire portfolio and can provide data on CO2 emissions from equity investments. This means that compared to previous years, CO2 data is available for a larger proportion of Aarhus University's portfolio of shares.
12. Typos for district heating in the greenhouse gas emissions report for 2022
As a result of a typo in Table 2 in the 2022, district heating emissions were reported as 3,650 tonnes of CO2 instead of the correct 3,797 tonnes of CO2. The error did not affect the overall calculations, as the correct number was used in the calculations.