5.2 General calculation process
The aim of this process is to calculate the environmental performance, measured as energy usage and emissions to air, of a cargo transport with a road vehicle. The result of the calculation will be expressed as kilo grams emission to air [kg] and use of energy [MJ] per shipment of X tonnes. The main steps in the calculation are presented below.
1. Collect information about the shipment
The shipment weight, volume and used cargo holders
2. Selection of relevant vehicle type and load capacity utilisation
NTM presents 10 different vehicle concepts. The environmental performance improves significantly as the load capacity increases with larger vehicles.
3. Vehicle operation distance and road types
Find the relevant distance the vehicle travels related to the transport of the investigated cargo shipment. If possible find the share of distance on different road types.
4. Set fuel type and fuel consumption (FC)
The calculation depends on the fuel type due to its content of carbon, sulphur and aromatic hydrocarbons. The exhaust emissions are calculated from the fuel consumption of the selected vehicle. Average default values [l/km] are given for full and empty vehicles on urban roads, rural roads and motorways. The user should seek to obtain fuel consumption data for the specific transport in order to increase accuracy in the result.
5. Set emission factors and energy content of the fuel
6. Calculate vehicle environmental performance data (energy use and emissions to air) for the operation of the vehicle
For HGVs and LGVs – emission values are given for relevant engine types in the unit [g/l] fuel.
7. Compensate for the effect of applicable exhaust gas abatement techniques
Reduction potentials for filters and catalyst are presented.
8. Allocation to investigated cargo
Calculate the share of the environmental performance data (energy use and emissions to air) that is related to the investigated shipment/cargo. Data for load capacity and default capacity utilisation is given.
The principal calculation process tree