Scope 3 category 7: employee commuting and homeworking

Category 7 "includes emissions from the transportation of employees between their homes and their worksites." Unlike business travel, there is no booking system to export from, so the data usually comes from a short staff survey. See the 15 Scope 3 categories for how it fits with the rest of Scope 3.

Methods

The GHG Protocol's guidance describes three methods:

• Fuel-based: "determining the amount of fuel consumed during commuting". Rarely practical, because employees do not track fuel per commute.
• Distance-based: "collecting data from employees on commuting patterns", that is, distance and mode. This is the usual method.
• Average-data: estimating emissions from average commuting patterns, such as national statistics, when no employee data is available.

The distance-based formula

For each employee, annual commuting distance by mode is the daily one-way distance × 2 × the number of commuting days per year. Emissions are the sum, across modes, of distance × the emission factor for that mode (per vehicle-km for cars driven alone, per passenger-km for public transport).

Running the survey

The guidance says "Companies should survey their employees annually to obtain information on average commuting habits", and where a full survey is not practical, "Companies may extrapolate from a representative sample of employees."

A survey needs only a few questions:

1. Usual one-way distance from home to work (km).
2. Main mode: car (fuel type, alone or shared), motorbike, bus, train, underground or tram, bicycle, walking.
3. Days per week in the office, and weeks worked per year.
4. Days per week working from home.

If 40 of 50 employees respond, scale the respondents' total by 50 ÷ 40, and record the response rate and the scaling in your report.

Worked example

Twenty employees drive an average 15 km each way, three days a week, for 46 weeks; ten employees take the train 25 km each way on the same pattern. DESNZ 2026 factors:

If employees report their fuel type, use the specific factor: an average battery electric car is 0.02951 kg CO2e/km in the DESNZ business-travel factors, against 0.17265 for diesel and 0.16152 for petrol.

Homeworking

"Companies may optionally calculate the emissions of teleworking from home." DESNZ publishes homeworking factors per full-time-equivalent working hour: 0.32393 kg CO2e covering office equipment and heating, or 0.02159 for office equipment alone.

If the same 30 employees also work from home two days a week for 46 weeks at 7.5 hours a day, that is 30 × 2 × 46 × 7.5 = 20,700 FTE hours × 0.32393 = 6,705 kg CO2e. Homeworking can be a large share of category 7, so include it, or explain why you left it out.

Common mistakes

• Counting company cars twice. Commuting in a company car whose fuel you already report is in Scope 1; do not add it to category 7.
• Forgetting holidays and sick days. Use actual commuting days, not 52 × 5.
• Using an old survey. Hybrid working patterns change quickly; repeat the survey each year.