ecoinvent Forum Archive

Hi to everybody,When using trasportation models for lorries "1 tkm" is the defoult unit, then I would like to know if 1tkm already considers the weight of a lorry or not.Then if I want to model a journey/trip whitout any load, do I have to insert only the distance? Or in order to otbain 1 tkm the model considers that a lorry of 5t has travelled for a distance of 0,2 km? (5t*0,2km=1tkm)Thanks in advance, I will strongly appreciate yours reply.Regards,breve

Dear user, 

The lorries account for an average vehicle weight and average load.

The average load assumed for the different lorry types is recorded in the general comment of the respective transport activities (see table below). 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.

*Note:  The freight, lorry >32 metric ton represents an average of transport with 24-40 and 40-60 ton lorries. According to the available statistics, the average payload of those two classes are 15.6 tons and 22.8 tons, respectively. The average payload was therefore calculated as the weighted average of the average payloads, giving 95% of the weight to the 24-40 ton class and 5% to the 40-60 ton class.

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).

Best regards, 

Lucia Valsasina, Project Manager, ecoinvent Association

Dear Lucia, thanks a lot for your reply, it is very detailed and clear. Anyway I need to know a key point, that is still not clear to me, sorry for this inconvenience and insistence.

I am using Ecoinvent in the software SimaPro, and then I have to model a trip (one way, without take into account the empty return trip), the distance is 30 km by means of a lorry that transport a load of around 5,7 ton. So based on the table you posted in the reply, I should just choose the entry "Lorry 16-32t" and then put as value the distance, 30 km; or I have to moltiply the load with the distance, i.e. 5,7t*30km?

This, as you know is crucial because can stronlgy affect the results.

I hope I was clear enough and thanks again in advance.

Best regards,

breve

Dear Breve, 

The unit of transport is tkm. tkm are calculated by mutiplying the amount of good transported (t) and the distance (km). 

If you select the 16-32t lorry with amount 5.7t*30km it would represent the transport of 5.7t for 30km in a lorry that has a load of 5.79. This does not represent an empty trip per se but the lorry has a rather low load, 5.73t, when the maximum load for this category would be (16-32t) - (10t, i.e. the weight of the vehicle). 

If transport has a strong impact on your study and it is therefore part of your foreground, you may want to consider modelling transport more closely to your needs. The ecoinvent database is a background database.

Best regards, 

Lucia Valsasina, Project Manager, ecoinvent Association

Dear Lucia, thanks again for your efficient support.

Now it's clear.

Best regards,

Breve

Hello, 

I have been searching MgCl2 in the database and I haven't found. Is this product not available on the database? 

Thank you very much. 

Dear User,

To get an overview about the datasets present in the database, please have a look at the activity overview https://www.ecoinvent.org/files/activity_overview_3.7_undefined_public.xlsx which provides a list of all datasets present in the current version of the database. You can filter by processes (“activity name”) or products (“product name”), ISIC and CPC classification, geographies and more. In the tab “Intermediate exchanges” you can also filter for CAS number and synonyms. Please keep in mind that ecoinvent is a background database and as such mainly contains more generic datasets. However, if you need datasets which do not exist in the database, ecoinvent also provides a good background for creating specific datasets on your own.

I hope this answers your question. If you have more questions, we kindly ask you to open a new thread for your question with a corresponding title, so other users can see it if they have the same question.

Kind regards,

Daria Dellenbach, Junior Data Analyst, ecoinvent association