Emission Allocation Method

Introduction

The purpose of this page is to explain the allocation method in accordance with the international recommended guidelines described in the GLEC framework.

 The goal of this method is to distribute the emissions emitted during a trip between the various stops.

Requirements

To apply this process, it is required to know:

• The total emissions emitted during the trip
• The loading and unloading at each stop of the trip
• The entire trip must be taken into account, from the vehicle's departure to its return to the depot. The last waypoint must always be the depot or the final end of the trip.

Allocating emissions

To divide emissions generated during a trip, the allocation method defines two criteria to compute an emission intensity or "notional transport performance" for each delivery point:

1. The distance: The great circle distance (km) between the depot and the delivery point (described below)
2. The quantity: The sum of what has been loaded and unloaded during the stop. This quantity can be either a volume (m³) or a weight (t) 

Then, the assignment of emission values to every order is carried out as follows:

1. A notional transport performance is determined as the product of the distance and the quantity.
2. These notional transport performances of all orders of the trip are added up.
3. For each order, its share (in %) of the sum of the notional transport performances is determined.
4. According to these shares the emission values of the entire trip are distributed to the stop / orders.

Great circle distance

To measure the distance between the depot and  a delivery point, the method is using the great circle distance (also called orthodromic or spherical distance). It is the shortest distance between two points on the surface of a sphere. 

For a depot (longitudeA,latitudeA) and a delivery point B (longitudeB, latitudeB):

R is the terrestrial radius (~6371 km)

This formula is known as the Haversine formula.

Emission Intensity 

When reporting emissions, you should also compute the emission intensity. It is the emission rate of CO2e (kg CO2e) relative to the intensity of delivery (t.km).

- WTWCO2emitted: The total Well to Wheel CO2 emitted during the trip
- Sum of all great circle distances in km
- Sum of all transported quantities in t

Example: 6 delivery points trip

In this example, the vehicle served 6 delivery points before returning to the depot.

• The vehicle is deposited in the same place on departure and arrival.
• The vehicle starts from the depot with an initial load of 8t.
• A fuel consumption of 8L is measured for this trip, with GASOLINE fuel type.
• The great circle distance (in green) is computed between the depot and every delivery point.
• The quantity of goods (here the quantity is a weight in t) that were loaded and unloaded during the trip are reported for every delivery point.

 For each delivery point, compute the notional transport performance :

The sum of all notional transport performances is 12.3 + 11.85 + 51.5 + 34.5 + 16.4 + 15.05 = 141.6 km.t

Then, for each delivery point, compute the share (%) of the sum of all notional transport performances.

With these shares, use the emission factors of an emission standard to generate emissions report.
With the standard ISO14083_2023 emission factors, a GASOLINE fuel type and a fuelConsumption of 8L, the PTV Developer Routing API indicates that 26.24 kg CO2e TTW and 31.2 kg CO2e WTW were emitted during the trip.

With the total emissions, use the previously computed order's shares and the total emitted emissions to compute the CO2e emissions of each order.

For the the emission intensity, compute:

• The sum of the great circle distances in km:
• The sum of all transported quantities in t:

The emission intensity is