Calculating emissions from employee commuting

The One Tonne Rule of Thumb

Rule of thumb: One tonne of CO2e per employee per annum for Scope 3 emissions from employee commuting and business travel.

Applying the 1 tonne (t) CO2e per employee per annum rule of thumb gives businesses a reliable benchmark for Scope 3 emissions reporting from employee commuting and business travel.

Analysing real-world emissions data for an average UK car, and modelling CO2e emissions based on factors such as the car's age, mileage, and the known deviations of NEDC- and WLTP-rated CO2 emissions from real-world driving conditions provides accurate and effective emissions reporting - essential for organisations seeking to reduce their carbon footprint and achieve sustainability goals.

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GHG Protocol: Category 7

Employees “Employees” refers to employees of entities and facilities owned, operated, or leased by the reporting company. Companies may include employees of other relevant entities (e.g., franchises or outsourced operations) in this category, as well as consultants, contractors, and other individuals who are not employees of the company, but commute to facilities owned and operated by the company.

one tonne rule of thumb

Step-by-step methodology

The "one tonne rule of thumb" approach estimates Scope 3 emissions from employee commuting and business travel by applying real-world vehicle data. Using five steps, it factors in actual driving conditions, vehicle ageing, and additional pollutants to provide an accurate assessment of the annual CO2 emissions of employees using their own cars.

1. Employee Commuting
To and from work
The average UK employee commutes about 1,785 miles per annum by car. This accounts for a significant portion of Scope 3 GHG emissions. By applying adjusted CO2 emissions rates (in g/km) to this commuting mileage, companies can estimate the annual CO2 emissions generated specifically from employees’ commutes.
2. Business Travel
Grey fleet mileage
Work-related "grey fleet" mileage in the UK is about 765 miles per annum. By applying real-world CO2 emission rates (in g/km) to this distance, we estimate the total CO2 emissions generated from business travel. This forms another key component of Scope 3 GHG emissions reporting for organisations.
3. Real-World Adjustment
Bench test uplift
An average car in the UK (from a car parc of 35 million cars) is a petrol model with New European Driving Cycle (NEDC) "bench test" emissions of 150g CO2/km. Real-world driving conditions, however, increase emissions by 30% to 50%, resulting in actual emissions of 195g to 225g CO2/km.
4. Vehicle Degradation
Wear and tear effect
The same average car has 61,820 miles on the clock and is about 8.5 years old. As cars age and accumulate mileage, emissions increase due to engine wear. Factoring in an 18% rise due to age, the real-world adjusted CO2 emissions increase further, providing a more accurate emissions estimate
5. Non-CO2 Pollutants
Everything else
Beyond CO2, cars emit other pollutants like nitrogen oxides (NOx), sulfur oxides (SOx), and methane (CH4). To account for their contribution to global warming, we apply a 10% to 15% uplift to the CO2 values, converting them into CO2 equivalent (CO2e). This gives a fuller picture of total greenhouse gas emissions.

Calculating Emissions from Employee Commuting

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1. Informed decision-making
Data Collection
Start by amassing precise and comprehensive data pertaining to employee commuting. Capture variables such as distance travelled, chosen mode of transport, and the frequency of travel. This foundational step sets the stage for accurate emission calculations and informed decision-making.
2. Credible assessment
Emission Factors
Leverage emission factors tailored to each transportation mode, be it cars, buses, trains, or others. Access these factors from authoritative sources like the Vehicle Certification Agency (VCA), Worldwide Harmonised Light Vehicle Test Procedure (WLTP) and transportation authorities. By utilising these recognised standards, businesses ensure the credibility and reliability of their emission assessments.
3. Systematic approach
Calculation
Combine the accumulated data to perform meticulous calculations. Multiply the number of employees by their commuting distance and frequency, and further by the emission factor corresponding to each mode of transportation. This systematic approach yields a quantified representation of emissions stemming from employee commuting activities.
4. Alignment with reporting standards
Conversion
Transform the calculated emissions into a universally understood metric: CO2 equivalent units. Achieve this conversion by applying established conversion factors. This translation enhances the comprehensibility and comparability of the data, facilitating effective communication and benchmarking.
5. Develop decarbonisation strategies
Data Analysis
Summate the emissions derived from employee commuting calculations to unveil the comprehensive carbon footprint attributable to this facet of business operations. This analytical step offers a panoramic view of the environmental impact, enabling companies to identify patterns, prioritise interventions, and develop targeted strategies for emissions reduction.

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Calculation benefits

1. Accurate Reporting
Accurate Reporting
By aligning with the rigorous GHG Protocol standards, your company ensures a robust and transparent approach to carbon reporting. This solidifies your environmental accountability and instils stakeholder trust through credible emissions disclosure. Compliance with these industry-recognized benchmarks fosters a culture of responsibility while reinforcing your commitment to carbon neutrality.
2. Informed Decision-Making
Informed Decision-Making
Unveil the intricacies of your carbon footprint and uncover emission hotspots through meticulous employee commuting emissions calculation. Armed with data-driven insights, your business can strategically optimise transportation choices. This empowers you to make informed decisions that seamlessly integrate sustainability into operations, reducing carbon impact and fostering a greener future.
3. Sustainability Goals
Sustainability Goals
Tracking progress toward reduction targets becomes a tangible endeavour as you quantify and manage employee commuting emissions. These measured strides contribute not only to your specific reduction objectives but also to broader sustainability aspirations and global climate action initiatives. Your commitment to reducing emissions underscores your dedication to being an environmental steward and driving meaningful change.
4. Employee Engagement
Employee Engagement
Equip your workforce with meaningful data on commuting emissions, sparking a sense of empowerment and shared responsibility. Employees gain insight into their carbon contributions, fostering a culture of environmental mindfulness and innovation. As a result, your organisation cultivates a team that actively participates in eco-conscious practices and fuels a collective drive toward sustainable solutions.
5. Investor Appeal
Investor Appeal
Elevate your investment appeal to environmentally conscious stakeholders by showcasing a resolute dedication to carbon reduction and climate-conscious operations. By quantifying employee commuting emissions, you demonstrate a tangible commitment to sustainability, aligning seamlessly with ESG-focused investors' priorities. This robust environmental management approach amplifies your attractiveness as an investment target, positioning you as a trailblazer in responsible business practices.

Calculating emissions from employee commuting

The One Tonne Rule of Thumb

GHG Protocol: Category 7

Step-by-step methodology

1. Employee Commuting

2. Business Travel

3. Real-World Adjustment

4. Vehicle Degradation

5. Non-CO2 Pollutants

We'll crunch the numbers for you

1. Informed decision-making

2. Credible assessment

3. Systematic approach

4. Alignment with reporting standards

5. Develop decarbonisation strategies

Calculation benefits

1. Accurate Reporting

2. Informed Decision-Making

3. Sustainability Goals

4. Employee Engagement

5. Investor Appeal

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