6. Indirect business-related emission factors

This section includes guidance and emission factors relating to indirect (Scope 3) emissions from business activities not covered in other sections.

6.1 Overview of changes since previous update

The three working from home emission factors decreased by around 5.5 per cent, as a result of the lower electricity, and electricity transmission and distribution loss emission factors.

6.2 Emissions associated with employees working from home

This section provides three emission factors, which incorporate typical emission sources associated with the activities of employees working from home. Employers can use these emission factors to estimate the indirect (Scope 3) emissions associated with staff working from home. The three emission factors for working from home are:

• Working from home – Default

• Working from home – Without heating

• Working from home – With heating.

All three emission factors have been developed based on typical uses of the following emissions sources by staff members working from home a laptop plus monitor, lighting and optionally heating. The default factor assumes heating is run for five months of the year and could be used where more granular data on the actual use of home heating is not available.

Should an entity wish to quantify their employees’ working from home emissions in more detail, they can survey staff and use the data provided in Table 13, or various emission factors from other sections in this guide.

Note the Working from home – With heating factor should only be used when heating is additional to what would normally be used. In other words, when the heater is being used over and above the normal home heating use. Noting this factor assumes six hours of heating per day.

Table 13: Working from home emission factors

6.2.1 GHG inventory development

To calculate the emissions for an employee working from home, collect information on the number of days staff have worked from home during the reporting period. You will need to record which of these days heating was used and which it wasn’t. If you do not have this data, use the default factor. Applying the equation E = Q x F (section 2), this means:

E = emissions from the emissions source in kg CO₂-e per year

Q = number of employees working from home without heating (days)

Qh = number of employees working from home with heating (days)

F = emission factor from the second row of Table 13

Fh = emission factor from the bottom row of Table 13.

WORKING FROM HOME EXAMPLE CALCULATION

6.2.2 Emission factor derivation methodology

To calculate the working from home emission factor, we decided the most appropriate unit would be employee days. Therefore, we would need to calculate how much electricity an employee typically used per day.

It is assumed for both the with and without heating emission factors a working day is 8 hours and all staff use a laptop, monitor and a 12W LED light.

Table 14 shows the emission sources used to derive the working from home factors. The default factor assumes heating is run for five months of the year, assuming a mix of heat pump and portable heater use. The without-heating factor only includes the office-based emission sources. The with-heating factor assumes 50 per cent of staff use electric portable heaters while 50 per cent use heat pumps. It is assumed heating used an average of six hours per working day, each heater type operating for three hours.

Table 14: Data used to calculate the emission factors

6.2.3 Employee commuting

To account for the emissions produced by employees commuting between their homes and their worksites, refer to travel emissions in section 7

6.2.4 The emissions benefits of working from home

There is ongoing discussion and research on whether working from home reduces an employee’s carbon footprint.

The carbon benefits of working from home will depend on, among other things, whether avoided emissions are seen from employee commuting. For example, an employee who normally commutes by car for a return trip of 40 km will see a decrease in overall emissions from working at home, whereas someone who normally takes the train or drives an electric vehicle may see an increase in their overall emissions (the sum of that employee’s emissions from working at home and commuting).

Similarly, through the increased use of collaborative technologies such as video conferencing and screen-sharing, there may be less need for certain workers to use company vehicles to visit and meet people in person. This would be expected to reduce the entity’s vehicle fleet emissions and, in combination with working from home, reduces the employee’s carbon footprint.

6.2.5 Assumptions, limitations and uncertainties

In the absence of accurate data for New Zealand, a number of assumptions have been made to establish a single default working from home emission factor. It is assumed that all staff use a laptop and one monitor, while in some cases desktops or multiple monitors may be used. There will also be variation in the wattage of the laptops being used, due to factors such as size and the way it is being used.

Acknowledging the likely high variation in the way New Zealand employees heat their office space, there is high uncertainty in this factor. It does not account for situations where unzoned central heating is used to heat the office space, for different heater sizes or for different heating fuels (eg, gas, solid fuels). Further, the assumed six hour running time may not apply in all cases, with some workspaces being better insulated than others. Future updates to the guidance will explore regional averages for heating type and duration.

The default factor assumes heating is used for five months of the year, which again is not likely to reflect all situations.

Given the above limitations, there is opportunity to improve your quality of data behind your inventory through having effective data collection, such as the staff survey suggested above. Since working from home is now ingrained in many New Zealand workplaces, routines have likely developed where many employees are consistently working from home on the same day(s) of the working week. In such cases, it may be relatively easy to ask employees to record which days they work from home, and which days where heating was used. Building on this with more accurate GHG data on employee commuting (which can be included in travel emission factors, section 7), will help you understand whether working from home is positively or negatively impacting your carbon footprint.

6.3 Guidance on the use of cloud-based data centres

Emissions from data centres come under indirect (Scope 3) emissions. These emissions may be significant for any entity that operates with large third-party IT infrastructure.

Due to the diversity and country location of data centres used by entities in New Zealand it is not possible to produce a single emission factor that would inform users of the kg CO₂-e each gigabyte of data produces.

Therefore, entities seeking to find out what the footprint is of the data centres where their ‘cloud’ is stored should contact the providers of their data centre to request this information. Large data centre providers are calculating the total emissions from their data centres and may be able to inform users of the carbon footprint of their usage. Examples of products or tools offered by data centre providers include the Google management tool Carbon Footprint, Microsoft’s Emissions Impact Dashboard and Amazon’s Customer Carbon Footprint Tool.