ecoinvent Forum Archive

A very basic question: I would like to consider freight transport in a foreground dataset from point A to B. I would like to also consider the necessary empty-loaded return trip from point B to A.

As I could read in the data quality guideline for ecoinvent v3 here  Chapter 4.6:"The freight transport products describe the transport services in metric ton-kilometres with average load factors that include the average share of empty return trips." My questions are:

1. Does this mean that in order to achieve what I wish, I need to use the roundtrip distance from A to B as the multiplier (i.e. distance A->B*2)?

2. How are the empty return trips considered in the average load factors? For example, in dataset "transport, freight, lorry 16-32 metric ton, EURO6", how is the average load factor (5.79t, as can be found in the dataset documentation) calculated considering empty return trips?

Thanks.

Dear user, 

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.

At the moment, the load cannot be changed in ecoinvent. If a user wants to modify it, he/she/they will need to apply their own modifications/assumptions.

For example, wear emissions depend on the GVW, so you can change them according to the load factor you want to consider by following the mathematical relation reported in the exchange.

Other emissions, such as heavy metals, depend on fuel consumption. You could then modify the fuel consumption based on your load factor and scale these emissions according to fuel consumption.

Emissions from lorry also heavily depend on road conditions (paved or unpaved), driving conditions (traffic), driving behaviour (ability of the driver), etc. In ecoinvent these are set as average conditions following The Handbook Emission Factors for Road Transport (HBEFA).

In your specific case, I would suggest you use the dataset "as is" considering the km (from A to B + from B to A) and the tonnes ( t transported from A to B + t transported from B to A [0 t if empty]).

Best regards, 

Lucia Valsasina, Junior Project Manager, ecoinvent Association

Just to ensure, since the transport dataset is only available in the unit of ton*km, it means I just need to use:

transport distance from A to B * transport weight of goods and containers + transport distance from B to A * 0 (empty load transport from B to A), which equals to transport distance from A to B * transport weight of goods and containers only, right?

I would be so thankful if you could please respond to the last question (above question). Actually, it is my question as well.

"Just to ensure, since the transport dataset is only available in the unit of ton*km, it means I just need to use:

transport distance from A to B * transport weight of goods and containers + transport distance from B to A * 0 (empty load transport from B to A), which equals to transport distance from A to B * transport weight of goods and containers only, right?"

I do not really understand at which point in the model the load factor is applied. is it a scaling parameter for some of the direct emissions in the transport freight lorry dataset, or somewhere else in the product system? 

Dear user, 

The load factor information is taken into consideration in the datasets delivering the service of transport, e.g. "transport, freight, lorry 7.5-16 metric ton, EURO5". 

The assumed load factor is used to determine fuel consumption and therefore the fuel dependent emissions, as well as the GVW (gross vehicle weights) used for the relevant emissions. See more in my previous response. 

I hope this clarifies.

Best regards, 

Lucia Valsasina, Project Manager, ecoinvent Association