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OMIT – Manual for environmental calculation of international freight transport

Enclosure A

Enclosure A.1
Data basis truck

Data for a 40 tons truck are not available in TEMA2000 at present; therefore the calculations are based on a 48 tons truck. These two truck types and the transports they carry out being different in many ways causes errors in the result. Using realised diesel consumption figures in OMIT, these errors are expected to be insignificant.

The energy content in diesel is 36.295 MJ/l - at 42.7 MJ/kg diesel, 850 g / l diesel.

Km/l is found by dividing 36.295 by "Energy consumption in MJ per km" from the result sheet.

We refer to TEMA2000 for further documentation.

The calculations are based on simulation in TEMA2000 as showed in table 3.

Table 1.
Energy consumption in MJ per km.

The emissions depend on the cargo on the truck. They are load dependant and are thus calculated on the basis of the consumption measured as MJ/km. Table 2 shows an example of the basis of the formula for an EURO 2 engine.

Table 2.
Formula for EURO II truck.

Table 3.
Calculation requirements in TEMA2000.

Travel speed in km/h - Share of trip in %.

In order to maintain OMIT as an operational tool, a number of the parameters in TEMA2000 have been set on default values. Table 3 shows the parameters used in OMIT for international transport.

There is an option for using different kinds of waste gas cleaning. These influence the emissions as showed in table 4.

Table 4.
Multiplication factor for waste gas technologies.

Finally it may be useful to include a short pre- or end haulage in OMIT, rather than calculating it separately. As the different engines have different emission profiles, it will cause an error. The energy consumption, however, will be correct, if you take basis in the realised km/l and distribute the emissions on the goods, which follow the model for the 40 tons trucks.

Hence the energy consumption and emissions are distributed on the goods by its share of the average goods weight or when voluminous goods, by the share of the transported volume. The calculation includes all driven km, and if the method is used for transported goods, all emissions and the energy consumption from the actual truck will be distributed on the goods. (Nothing will be "forgotten").

You can get an idea of the error by using the mentioned method and look at table 5, where data for 40 tons is compared with distribution trucks from TEMA2000.

Table 5.
Deviation in % per ton goods for distribution trucks from TEMA2000 for calculation in OMIT based on diesel consumption data and the used standard export truck and driving pattern.

As shown in table 5 there is no deviation for the direct diesel dependant components as energy consumption, SO2, and CO2. For the other components the deviations vary between 0 and 64%, mostly for a 10 tons truck. Thus it also appears that this approximate method can only be applied, when it is a matter of a limited part of the total transport.

Standard values for driving without load are 9%, EURO-norm is 1.5 and the average cargo weight of 16 tons is based on Danmarks Statistik, 2001:20.

Padborg, 2001.

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