CO2 calculation and Required Parameters

[CAPcargo]

Hello,

I’m currently working on implementing CO2 emission calculations using PTV’s Developer API and would appreciate some clarification regarding Emission Intensity and about the impact of weight parameters.

I'm referring to the Emission Intensity formula provided in your documentation. I guess we should calculate Emission Intensity by myself, and it is not provided as value in the response.

I would like to ask for clarification on the two components:

1. Sum of all great circle distances in km
   • Does this refer to the total route distance from start to end of the tour, or is it calculated per delivery leg (i.e. between each pair of stops)?
   • Is this value available directly in the response of the CO2 calculation, or do we need to calculate it ourselves based on coordinates?
2. Sum of all transported quantities in tons (t)
   • Does this refer to the sum of loaded quantities per delivery (i.e., per stop), or the sum of total vehicle load carried during the tour?
   • Is it required to track loading/unloading amounts at each stop to get accurate values, or is it enough to use the vehicle’s total loadWeight?
3. What is the purpose of Emission Intensity, and in which use cases is it typically applied?

Second topic is about the impact of weight parameters (emptyWeight, loadWeight, totalPermittedWeight) on CO2 calculation:

In our request to the PTV API (e.g. calculateRoute), we include the following weight parameters (in vehicle profile):

• emptyWeight
• loadWeight
• totalPermittedWeight

Do these parameters influence the CO2 (WTW or TTW) emission calculation directly?

• If yes, which of them has the most impact?
• In your sample CO2 requests or documentation, how are these weight fields typically provided?
• In our internal tests, changing these values does not appear to significantly affect the calculated CO2 values. Is there a minimum threshold, default fallback, or are we possibly missing other required parameters that link with these?

Any additional explanation for these topics would be very helpful to ensure our implementation is aligned with your expected data structure.

Thank you very much!
Best regards,
Irena

[Bernd Welter]

Here are some partial answers to your questions - I am also waiting for further details from our french colleagues.

You can find some of the answers on the technical concepts pages:

• routing-api/concepts/emission-allocation-method
• routing-api/concepts/reporting-emissions-respecting-international-guidelines

The relevant distances are those between the depot and the stop. It’s like you have to see each stop as an individual contributing factor.

• The response does return the emissions based on the transported quantities. Therefore the distances have to be computed either via GCD (great circular distance) or via SFD (shortest feasible distance, based on routing from Depot to/from stop with proper settings)
• the transportedQuantities are the quantities per stop. Please be aware that the method described applies to DEPOT roundtrip based transports. If you are dealing with AB transports Pickup/Delivery like for parcels (A and B being stops in the middle part of the tour) you need another allocation methodology.
• The purpose of the approach described in the concept is to distribute the emissions on stop level. So you should use the loadWeigth.
• The purpose of "emission intensity" is to enrich emission reports which are probably more and more legally required in professional transportation business.
  • Emission intensity is typically expressed in terms such as grams of CO₂e per tonne-kilometre (gCO₂e/tkm) for freight. The purpose of this metric is to: Enable performance benchmarking, Support emissions reduction strategies, Enhance transparency and comparability in logistics emissions reporting, Align with international standards and reporting schemes (e.g., GHG Protocol, ISO 14083)
  • As the intensity is one average value for the whole trip its easy to compare different transports

• Do these parameters (emptyWeight, loadWeight, totalPermittedWeight) influence the CO2 (WTW or TTW) emission calculation directly?

  The answer depends on the emission method you choose: e.g. if you calculate the emission based on HBEFA then the values are used to derive the emission because these values are looked up in the HBEFA (handbook of emission factors).
  This “comprehensive approach” is also described in this article (xServer2) :
  The alternative is the so-called “factor based” approach described in this article

Your questions should be answered in the docs / links above. If you are missing info let us know in a way we can improve the documentation.

If you want a quick demo of the impact I can set up a session by myself – but that would roughly be based on simply showing 1:1 routes, changing the mentioned properties and visualizing the impact on the single output.

For a deeper discussion I can also offer a session with my "emission guru" Stephan, who already contributed to this response.

Best regards,
Bernd