The t.km approach is familiar and you recently helpfully clarified that the weight of a shipping container is accounted for on ships. In your road transport inventories, is the weight of a shipping container accounted for or should it be considered in addition to the load carried?
In short, if I carry 5 t goods in a 2 t shipping container for 100 km, should I use 500 tkm or 700 tkm (subject to the truck type being large enough to carry the container).
Many thanks
Adrian
Dear Adrian,
Thank you again for your question.
In order to relate transport modules to life cycles of other products and services the environmental interventions are related to the reference unit of one tonne kilometre [tkm]. A tonne kilometre is defined as: “unit of measure of goods transport, which represents the transport of one tonne of goods by a certain means of transportation over one kilometre”.
In your example, if you carry 5 t goods in a 2 t shipping container for 100 km, please use 500 tkm (subject to the truck type being large enough to carry the container).
The average load assumed for the different lorry types is recorded in the general comment of the respective transport activities. The average load factors are taken from the Tremove model v2.7b (2009) and EcoTransIT (2011) report, and are calculated as total tonne*km/total vehicle*km for each vehicle size. This implicitly includes empty return trips. At the same time it does not mean that a round trip is equal to a full + a empty single trip.
The average load is used to determine fuel consumption and relative emissions. In the general comment of the dataset you can find for each lorry size the information regarding the load factors and the gross vehicle weight. From this you can also calculate the net vehicle weight (GVW - average load). There is no differentiation between lorries carrying containers versus the ones that do not.
Best regards,
Lea Wollensack
Junior Data Analyst, ecoinvent