Types of emissions
Proper emission accounting requires looking at a full lifecycle of fuel. Direct transport emissions are not only what is coming out from the exhaust pipe: drilling and manufacturing of the fuel, transporting to the gas station has its own footprint which has to be taken into account. Also production of trucks, building and maintenance of roads, etc are part of transport emissions. This chain can go quite far, but in practice and according to the GHG Protocol the following scopes for fuel emissions are calculated:
Well-to-Tank (WtT or W2T) - production and transportation of one liter of fuel.
Tank-to-Wheel (TtW or T2W) - all what happens "after tank", i.e. direct emission of CO₂ (and other gases) from the vehicle internal combustion engine.
Well-to-Wheel - sum of the two above, total life cycle emission
By default only the last and biggest number is reported - Well-to-Wheel. All numbers can be in grams, kilograms or tons. Note that the indirect emissions (production of cars, roads, accidents, noise etc) are today not yet factored in, but these values can be approximated separately.
Key terms and definitions
For all the emission scopes we calculate different key emission values, which are available in carbon emission report dashboards:
CO₂e intensity or specific emission. Shows how much emissions are created to move one tonne of goods for one kilometer, i.e. how effective is the transport. This is a more suitable measure for comparisons than the raw CO₂e, because the total raw number depends also on the distance and the weight of goods. Unit: “grams per tonne-km”, meaning how many grams to move one ton for one km was emitted. Typical truck transport value is about 80 g per t-km, and lower value is better.
Carbon Data Index shows how good data input was given to be used for calculations. If only shipper data is given, then this is low (below 20%), if also carrier primary data is available then it is higher, up to 100%. Higher is better.
Scope 3 Coverage Rate: the share of transports that have emission calculated. In general we try to calculate at least default-based emissions for 100% transports, but sometimes it is not possible due to missing or incorrect data. Typical data issues are inaccurate addresses, missing stop coordinates or completely wrong coordinates so route cannot be found.
Total CO₂e - CO₂ equivalent, standard industry measure which factors in all emitted greenhouse gases (not only CO₂, but also methane etc) with their respective impact. Unit: metric tonne. Lower value is better, but if number of transports or distance increases then it goes up, so for comparison intensity is often better measure.
Transport Performance shows quantity of transports - in tonne-kilometers.
CO₂e reduction potential shows maximum reduction with “optimal scenario” which means lowest possible emission for specific set of transports/lanes. Usually the lowest emission is rail transport, so effectively this is difference between road and rail transport.
We are also internally calculating a few extra parameters that are used to calculate final CO₂e or provide extra data about emissions:
Primary energy - energy needed to execute the transport. This is the base value for calculations. Unit: MJ
NO - Nitrogen Oxides. Unit: kg
SO₂ - Sulphur Dioxides. Unit: kg
Non-methane hydrocarbons. Unit: kg
Particles - so-called "smoke". Unit: kg
CO₂ - Carbon dioxide emission. Unit: kg
Transport performance. Only applicable for T2W. Unit: tonnes
Transport distance. Only applicable for T2W. Unit: kilometers
Transport route geography. Useful to check the estimated route if no detailed route data was available from RTV and the calculation was based only only on the transport plan.
Accident and noise costs - an approximation for road accidents costs and problems created from road noise in EUR.
Emission costs - an approximation for emissions taxes in EUR.
Levels of calculation
We use following three main levels of calculation depending on the input data that is available for each transport:
Default calculation uses minimal data - loading and unloading locations. If available for given transport, we use weight, mode of transport and general truck properties (e.g. whether it is reefer), otherwise we use standard defaults.
Modeled calculation is more accurate and also takes into account the real route distance from RTV (telemetry we received from the allocated truck, trailer or IoT device), as well as more truck properties (if available).
Primary data calculation collects direct fuel consumption or CO₂ emission data from the vehicles (and trailer if applicable) and uses fuel conversion factors to get accurate values for emissions. Fuel consumption data is available from more advanced telemetry systems. By default we use base factor 3.17 kg Well-to-wheel (2.54 Tank-to-Wheel) CO₂e per litre of fuel for road.
Modeled and Primary calculation levels require that the carrier is providing proper RTV for specific transport. Visibility Hub shows clearly which level of calculation was used, and keeps different calculation levels as separate fields. Visibility Hub calculates RTV-based emissions at the end of the tour when we gather all relevant info about the transport. We keep track and can export all relevant parameters of the calculation, as well as specific tour metadata, like driven distance or measured liters of fuel. These can be made available for further validation and analysis.
Calculation input and defaults
Carbon footprint depends on several variables as input. We list the most important variables together with their defaults:
Estimated distance of the transport is mandatory. This is calculated from the shortest route between loading and unloading locations.
If RTV is working for specific transport, then we recalculate footprint based on real travelled distance. So if the real route was e.g. 30% longer then also the emission result would become correspondingly bigger.
Transport mode: road, rail, sea or ocean ship, air, inland waterways - all have very different footprints. Default: road. For "multimodal" transports we try to split them to single mode legs and give emission for each separately.
Gross weight of cargo. Default: 24 tons (for road).
Truck emission class (for road). Default: EuEuro6.
Empty run factor. Default: 20%.
Load factor. Default: 60%.
Type and size of vehicles: trucks, trailers (e.g. reefer creates extra emissions), ships, trails. Default for road: Class40.
Specific route: different road types, different countries etc may have different multipliers. Default: highway.
Fuel type. Default: diesel.
Bio fuel share. Default: 5.43%.
Used fuel amount. Default: assume average fuel consumption per km.
Note that default values may be different in cases when additional data about transport execution is available. Visibility Hub approach is to use as much data as possible from shipper and carrier for specific transports or from shipper/carrier profiles (master data). With more data we generally give more accurate calculations.
Visibility Hub calculation service will be certified by SmartFreightCenter for GLEC framework compliance.