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Shipping emissions

The vehicle emissions produced by a shipment

Last updated 17 May 2024

To calculate the vehicle emissions produced by a shipment, Skrym needs the following data points: the approximate route the shipment will take between the start and end location, the vehicle that will be used for each segment of the route, emissions factors for each vehicle, emissions factors for the fuel that is used by each vehicle, and package weight and volume.

If not all of these data points are available, Skrym uses first-hand data sourced from the relevant transporters but defaults to third-party records (such as Transportstyrelsen ) if the first-hand data is not available. If no data is available in third-party records, Skrym uses default values as fallback.

Route Estimation

The route that the parcel(s) take is estimated in these two simple steps:

Generating the assumed delivery route and breaking it into several segments to reflect stops at Terminals and Delivery Hubs.
Assigning the relevant vehicle (that corresponds to the appropriate transporter) to each segment of the route.

Emissions Factors

The function calculates average emissions factors. It prioritizes obtaining direct data stored for the specific vehicles available for that route. If this is not available, it falls back on the same information stored for the vehicle's model and its associated fuel. If there are no available vehicles for that route, the transporter's whole fleet for that route segment type is used. If no emissions factors are found, or if a vehicle fleet is lacking, the function falls back on using default constants derived by NTM.
These emissions factors are converted into a emissions-by-distance factor:

E^{\text{km}}_{i} = \sum_{v \in V_i} \frac{d_i}{100} \cdot e^{\text{fuel}} \cdot c_v

where $V_i$ is the set of available vehicles for route segment $i$ , $r$ is the distance of the segment, $e^{\text{fuel}}$ is the emissions factor for the fuel, and $c_v$ is the fuel consumption rate of $v$ .

Impact of Individual Shipments on Vehicle Emissions

Volumetric weight is calculated for the shipment, based on its dimensions: $w_{vol} = l \times w \times h \cdot 280 \times 10^{-9}$
Debitable weight is assigned by the greater of the volumetric weight and the actual weight of the shipment: $w_{\text{deb}} = \max(w_{\text{vol}}, w_{\text{act}})$ .
The function then calculates the emissions for each segment of the route, using the following formula:

E_{i} = E^{\text{km}}_i \cdot d_i \cdot a

where $E_{i}$ is the emissions for segment $i$ , $d_i$ is the distance of the segment $i$ , and $a$ is the allocation factor of the shipment. $a$ is defined by:

a = \left( \frac{w_{\text{deb}}}{U_{\text{cap}} \cdot W_{\text{max}}} \right)

where $U_{\text{cap}}$ is the capacity utilization of the vehicle, $W_{\text{max}}$ is the maximum load weight that the vehicle can createFactory.

Total Vehicle Emissions

The total emissions for the shipment is then calculated by summing the emissions for each segment $i$ of the route $R$ :

E^{\text{tot}} = \sum_{i \in R} E_i

Variable	Unit	Description
$E$	kg $\text{CO}_2$	Emissions
$d$	km	Distance
$e^{\text{fuel}}$	kg $\text{CO}_2$ /L	Emissions factor for fuel
$c$	L/100km	Fuel consumption rate
$w_{\text{vol}}$	kg	Volumetric weight
$w_{\text{act}}$	kg	Actual weight
$w_{\text{deb}}$	kg	Debitable weight
$a$	%	Allocation factor
$U_{\text{cap}}$	%	Capacity utilization
$W_{\text{max}}$	kg	Maximum load weight

Well-to-Wheel or Tank-to-Wheel?

Skrym's emissions calculation is based on the tank-to-wheel (TTW) approach, which means that we only consider the emissions produced by the vehicle itself, and not the emissions from the production of the fuel or the vehicle.