What’s changing

To align with the latest EPA and environmental audit standards, Workiva Carbon is removing outdated volume-based factors for CH₄ and N₂O originally published in the Greenhouse Gas Protocol’s Calculation Tool. If you track mobile combustion by fuel, additional steps may be required. Keep reading to learn what has changed for each style of tracking.

Mobile combustion by fuel 

Who is affected:  Customers who track mobile combustion by fuel, specifically for activities tied to locations in the United States or Canada.

What’s changing: The EPA provides fuel-based factors for CO₂. However, CH₄ and N₂O emission factors depend on the vehicle type and distance traveled, rather than just the amount of fuel used. Library V4 doesn’t support CH₄ and N₂O calculations based solely on fuel volume for locations in the United States or Canada. If you use "mobile combustion by fuel" for these regions in V4, the calculation will fail because the required factors are no longer available. Using “mobile combustion by fuel” in locations outside of the United States or Canada will have volume-based emission factors published by the UK DBEIS applied.

Required action: If you use emission factor library V4 and have mobile combustion activity in the US or Canada, go to Measure and select Vehicles. Click the configuration icon and make sure “Mobile combustion by vehicle" is switched on. To update your sources, go to Company profile and click Vehicles. Make sure to provide fuel type, vehicle class, and fuel efficiency. To learn more, view Measure vehicle emissions. When adding your activity data (either by a single entry or bulk upload), you can still provide fuel amounts only, but distance will now be estimated by the system using the fuel efficiency provided.

Mobile combustion by vehicle (when fuel volume is the only data provided)

Who is affected: Customers who track mobile combustion by vehicle and enter fuel volume only.  

What’s changing: Library V4 will not calculate CO₂, CH₄, and N₂O with volume-based emission factors for entries of only fuel volume. Instead, library V4 will estimate distance traveled using your input fuel volume and your vehicle’s fuel efficiency, and CH₄ and N₂O emissions will be calculated with distance-based emission factors specific to your vehicle’s class. 

Required action: None.

Mobile combustion by vehicle (when fuel spend is the only data provided)

Who is affected: Customers who track mobile combustion by vehicle and enter fuel spend only.  

What’s changing: Library V4 will not calculate CO₂, CH₄, and N₂O with volume-based emission factors for entries of only fuel spend. Instead, library V4 will estimate fuel volume and distance traveled using your input fuel spend, average fuel price, and your vehicle’s fuel efficiency. CO₂ will be calculated with the estimated fuel volume, and CH₄ and N₂O emissions will be calculated with the estimated distance traveled.

Required action: None.

Why were emission factors from different publications being used for different GHGs within the same calculation? 

Mobile combustion by vehicle 

The EPA does not publish volume-based CH₄ and N₂O emission factors for all vehicle classes, and the Greenhouse Gas Protocol’s calculation tools addressed that gap by including volume-based emission factors calculated with an average fuel efficiency by vehicle class. To produce vehicle-specific emissions results with only fuel input, emission factor library versions 1, 2, 3, and 3.1 would use the EPA and GHGP calculation tool’s emission factors in the same volume-based calculation. The GHGP calculation tool’s emission factors are considered out of date, and changes to the available calculation methods result from excluding them from library V4.  

Mobile combustion by fuel

The volume-based CH₄ and N₂O emission factors provided by the GHGP’s tools are vehicle class-specific, but fuel volume entries within Mobile combustion by fuel are not associated with a vehicle class. Emission factor library versions 1, 2, 3, and 3.1 included average CH₄ and N₂O values of all vehicle classes per fuel to enable CO₂, CH₄, and N₂O results when fuel volume is the only available input. These internally calculated values are replaced with volume-based emission factors published by the UK DBEIS in library V4.