🪄3. Result Calculation (LCIA)

Life Cycle Impact Assessment is the third step of an LCA - now it's getting interesting!

This phase is about calculating the environmental impact of the products. To do so, we must specify each product's background and foreground system.

• Foreground system

The foreground system, also known as the system under study, represents the specific product or process assessed in the LCA. It includes all the activities and stages directly associated with the production, use, and disposal of the product or process.

The foreground system focuses on the unique characteristics and attributes of the product or process, such as material composition, manufacturing processes, distribution channels, and end-of-life scenarios.

Data related to the foreground system are typically collected through LCI phase.

• Background system:

The background system refers to the broader context within which the product or process operates.

It encompasses all the upstream activities and inputs necessary to support the foreground system. These activities include raw material production, electricity or heat production for product's assembly.

Background data provides information about the environmental burdens associated with these upstream processes. This data is typically collected from databases, industry reports, scientific literature, and other secondary sources.

Now that we have specified the product system for conducting LCIA, we need to:

1. Choose background data (emission factors) from databases with high-reliability score

2. Map foreground- and background data (e.g., product materials and emission factors)

3. Use the PCF calculation engine to calculate the environmental impact

Databases for background data

In most cases, primary supplier data about the environmental impact of purchased goods (e.g., LCAs or PCF studies) are unavailable. In those cases, we use secondary background data from widely used, third party reviewed databases. These include:

• Ecoinvent 3.10

• EF 3.1

• Idemat 2024

• Agribalyse

• Base Empreinte V23

• World of Steel 2022

• published EPDs from suppliers

• Published LCAs in scientific journals

Mapping foreground and background data

Each product data point is assigned to an emission factor.

At this stage, our automated LCA engine maps product components to their attributed environmental data.

Calculate the results

Now, let's delve into calculating the results.

Below, we'll illustrate this process using the example of a plastic chair in a simplified manner. In practice, this analysis is automated in our LCA engine. Our LCA engine enables the assessment of entire product portfolios and intricate items with numerous components and non-linear supply chains.

PCF Calculation: Plastic Chair

Let's go back to our example of the plastic chair.

Product	Plastic chair
Weight	5,5 Kg
Composition	81% - PP (of which 50% is recycled) 19% - Steel
Production	Injection molded PP
Loss rate	3,5%

CF (Materials): How to calculate the carbon footprint of materials?

For the recycled material, we apply the CFF method and use an EF from Ecoinvent for the PP.

For the steel screws, the supplier has published an EPD, so we can use supplier specific data here.

The plastic is injection molded, there we have an assumed loss rate of 3,5 %. Therefore, the material carbon footprint (CF) is calculated as follows:

CF(Materials) = 4,5 kg * 1,035 * EF(PP,50recycled) + 1 kg * EF(steelscrewsY)

CF (Production):

How to calculate the carbon footprint of production process?

In the next step, the environmental impacts of the production are calculated.

Here we have two steps: First, the PP is injection molded. It means that the plastic granulate is transformed into the desired form.The injection molding process requires 12kWh electricity. The producer reported that they use the Italian grid mix. there is a material loss rate of 3.5 %.

The next step is the chair assembly. This process is done in a semi-automated way in Germany. The amount of electricity required per chair is 2.5 kWh. The producer reported that they renewable electricity.

CF(Production) = 12 kWh * CarbonIntensityElectricity(Italy) 
                + 2,5 kWh * CarbonIntensityElectricity(Renewables, Germany)

In most cases, these two phases account for the largest part of the overall PCF. Nevertheless, we still need to calculate the environmental impact of the transport and packaging. In a cradle-to-gate assessment, all upstream transport steps and packagings are considered until the product arrives at the production gate or the warehouse.

In our example, it's crucial to consider the journey of PP granulate from China to Italy via truck and ship, followed by its transit from Italy to Germany by truck.

We adjust for varying material weights due to the loss rate during the injection molding. Meanwhile, the Steel Screws travel from Poland to Germany. Notably, as we rely on the EPD provided by the Steel Screw Supplier, the raw material transport is already factored into the CF, ensuring we avoid duplicating these calculations.

CF(Transport) = 
        4,5 kg * 1,035 * 12.000 km * EF(ship) + 1.500 km * EF(truck)
        + 4,5 kg * 1.800 km * EF(truck)
        + 1 kg * 1.500 km * EF(truck)

For packaging, we include the product packaging of the final product, which is 1,2 kg corrugated carton (100 % recycled material) and a plastic bag which has a weight of 0.085 kg. The packaging of the steel screws is included in the EF from the supplier EPD and the PP raw material packaging is cut-off in this case.

CF(Packaging) = 1,2 kg * EF(corrugated carton, recycled) + 0,085 kg * EF(plastic bag) 

Adding up all CFs we get the final PCF excluding Safety Margin.

PCF(PlasticChair) = (CF(Material) + CF(Production) + CF(Transport) + CF(Packaging))
                 * SafetyMargin

-> Read more about how the Accuracy Score determines the Safety Margin here.