Transportation plays a role in the environmental impact of products, encompassing the movement of raw materials, goods, and waste across various stages of their life cycle. Understanding how to accurately model transport is essential for conducting comprehensive Life Cycle Assessments (LCAs) and optimizing sustainability efforts. This article answers the following questions:
How to calculate ton kilometers?
How to select transport datasets?
Are you a Mobius user and feel like you're missing information? This article is specifically on modeling transport in Mobius, check it out if you want to learn more.
How to calculate ton kilometers? The basis for modeling transport
Transportation impact is usually quantified using ton kilometers (tkm), representing the transport of one metric ton over one kilometer. It’s essential to know because ecoinvent, the most common database in Mobius, uses tkm as the unit of measurement for their transport datasets. Here's how to calculate it:
1. Identify variables: Before you get started, you must know the following:
Transportation method: Determine the mode of transport. For example, truck (lorry), ship, train, or airplane.
Note - Transportation method: One object may use several transportation methods. Be sure to account for all of them separately when modeling transport. Transportation methods can vary significantly in terms of environmental impact.
Distance traveled: Measure the distance between relevant locations, like supplier and factory. Kilometers (km) is the preferred unit for distance in Mobius.
Mass of transported goods: Obtain the weight of the product or raw materials being transported for each respective leg. Tons (t) is the preferred unit for mass for the environmental impact of transport.
Note - Distances: It is possible you do not know where your sourced material comes from. In this case, you can either (i) estimate the distance to still be able to estimate the tkms, or (ii) use ‘market for’ (ecoinvent) datasets that incorporate a representative amount of transportation within the dataset itself. In case you use 'market for' datasets, you don't need to model the transportation separately!
2. Calculate ton kilometers (tkms): Multiply the weight of the goods (in tons) by the transportation distance (in kilometers) to obtain tkm.
Example: If transporting 0.22 kg of bleach over 260 km, convert kg to tons (0.22 kg / 1000 = 0.00022 tons) and multiply by the distance (0.00022 * 260 = 0.0572 tkm).
Exceptions: Cases to adjust ton kilometers (trucks/ lorries)
In most cases, trucks drive one leg of their round-trip journey full of goods and drive the second (return) leg empty where they collect their next delivery. Ecoinvent's approach to modeling transport assumes this to be the case. Put differently, ecoinvent's tkm approach factors in both journeys - one full and one empty - allocating the environmental impact attributable to your material, component, or final product. Ecoinvent's approach is considered a worse-case approach to modeling transport.
Pro tip - ecoinvent's worse-case approach: Logistics data often lacks the detail to know whether the truck goes back empty or full. When in doubt, it is always better to model a worst-case approach as the default baseline.
If you do know the details of your logistics partner's round trips, you can consider this in your LCA model. If you know your truck always drives full both ways in its round-trip journey, correct and apply a factor of 0.625 to your tkms. The truck's environmental impact is lower when more goods are transported because the impact is 'shared' and divided over more goods.
If you have other, more niche logistical cases to cover, do not hesitate to contact the Ecochain Helpdesk, or schedule a free Support call.
Video tutorial
Watch Emma explain these concepts in our tutorial:
How to select transport datasets in ecoinvent?
Finding the right dataset is crucial for accurately estimating the impact of your LCA's inputs. Here are some strategies to streamline the process for transportation datasets:
1. Select a database: Utilize the filter tool to choose a database (version) in Mobius, like Ecoinvent (v3.8), to access a wide range of transport datasets.
2. Search for keywords: Use specific keywords (e.g., "transport," "freight," "sea") to narrow down search results and find relevant datasets.
Pro tip - Keywords: Use the following terms to help ease your dataset search process.
Transport: Transport in general.
Unspecified: Average transport mode (with average load capacity and engine emission standard). Most users use this when they don’t know the average load capacity or engine emission standard.
Lorry: Transport by truck.
Lorry with reefer: Transport by truck with refrigeration
Freight: Transport of goods.
Passenger: Transport of persons.
Sea: Transport by sea.
Air: Transport by air.
Container ship: Transport of a container by ship.
Container ship with reefer: Transport of a container by ship with refrigeration.
EURO3-6: The EURO emission standard of a truck: from 3 to 6.
Metric ton: There are small, medium, and large-sized trucks available. The size of a truck is expressed in loading capacity. The following options are most frequently used: 3.5-7.5 metric ton, 7.5-16 metric ton, 16-32 metric ton, >32 metric ton
3. Filter options: Use filtering options based on category (e.g., ‘Transportation and storage’) or location to refine your search.
Video tutorial
Watch Emma explain these concepts in our tutorial:
Next steps
By following these tips & tricks, you can effectively model transport, ensuring that transportation impacts are accurately captured in your LCA models. For further assistance or guidance, explore our help center resources or reach out to our support team. Happy modeling!