Understanding everything about life cycle assessment (LCA)

1. What is LCA?

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Life cycle assessment or analysis, known as LCA, is a method of quantifying the environmental impacts of a product, process or service by taking into account all the stages of its life cycle: from the production of raw materials to the end of life through manufacturing or transport.

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Also called cradle-to-grave analysis, LCA has established itself as the reference method for evaluating the environmental impacts of a product or service. First of all because it is interested, as we said, in all stages of the life cycle but also because it integrates a multi-criteria approach. The LCA compiles all the incoming and outgoing flows associated with each stage of the life cycle of the product or service. For incoming flows, it may be raw materials or energy (oil, electricity, water) for example. And waste, emissions or liquids released for outgoing flows.

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And since we are talking about a multi-criteria approach, it is necessary to clearly define and understand the different types of LCA that exist.

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• ACV iso compliant

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It is the complete LCA, the one that complies with the standards ISO 14040 and 14044.

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It is a multi-criteria LCA because it allows you to look at all the impact indicators of a product or service: climate change (through CO2e emissions) but also depletion of the ozone layer, emissions of fine particles, acidification of land and fresh water or even eutrophication of fresh water. These indicators are very numerous. And it is possible not to analyze all of them. Depending on the product or service on which the LCA will focus, the company may choose to select only a few indicators. The vision of the impact of the product or service analyzed may be a little less comprehensive but more global.

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To make one, you have to follow 4 main steps:

• definition of the objectives and the field of study
• life cycle inventory (LCI)
• impact assessment
• interpretation of results

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We will detail these 4 steps later in the article. The level of granularity of the data is adapted to the objectives of the study. The results of the LCA are the subject of a report which must also include the hypotheses used and the data collected. It is this report that is finally assessed by one or more third parties. This is what makes it possible to validate the results of the study.

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• LCA made easy

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This LCA uses the same process as an ISO 14040 LCA: we define the objectives and the field of the study, we collect the data, we evaluate the impacts and we interpret the results. However, simplified LCA may be “content” with secondary data or may focus on certain indicators rather than others depending on the product or service being studied. Another difference is that the simplified LCA report does not have to be assessed. This type of study is very often used by companies to carry out ecodesign studies and/or compare several products internally.

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• Carbon LCA or Product Carbon Footprint (PCF)

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This LCA corresponds to the ISO 14067 standard. This methodology, also called Product carbon footprint (PCF), will make it possible to look only at the greenhouse gas (GHG) emissions of a product or service, thus giving a precise idea of the carbon impact of the observed system. Again, the analysis covers all the stages of the life cycle of the product or service and can be used to identify precisely the stage that has the most impact on the total carbon footprint. PCF can be used for the purpose of eco-designing a product. But it has its limits: what is good from a carbon point of view is not always good for other environmental indicators (on biodiversity for example) and there may therefore be transfers of impacts on other indicators.

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2. Why do an LCA?

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On this subject, you can consult our article: which LCA for which strategy?

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More and more companies have understood the importance of having a good understanding of the environmental impact of their products. Carrying out a carbon footprint allows us to have a first vision of this impact. But it is a very global vision, at the company level and only on the climate change indicator. This is where LCA comes in handy: it makes it possible to zoom on the environmental impact of one or more products or services rather than on the climate.

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• An ecodesign approach

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Ecodesign, according to the ADEME definition, “makes it possible to reduce the negative environmental impacts of products, processes, or services over their entire life cycle”. Clearly, its objective is to reduce all the environmental impacts of products from the moment they are designed.

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And to implement this approach, the first step is to assess the environmental performance of products or future products. It is from this analysis that the company will then be able to work to improve the performance of its products. LCA allows a company to know where the main impacts of its products or services are in their life cycle. LCA also makes it possible to compare two or more products internally, to compare one of its products with the competition or to compare a current product with an alternative.

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A Product carbon footprint (PCF) can be used in an ecodesign approach with the limitation already mentioned earlier that this analysis only focuses on the impact on climate change and that there may be a transfer of impacts to other indicators. The ideal tool for ecodesign remains a multi-criteria LCA in order to be able to determine the overall environmental performance of the system studied. And multi-criteria LCA can be a simplified LCA if the results are not published or are not used to publicly compare several products with each other.

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• Communicate on the environmental performance of its products

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More and more companies want to communicate about the environmental impact of their products or services. LCA is therefore essential in order to make environmental claims. In this case, to communicate publicly on the impact of a product or to publicly compare several products, it is necessary to carry out a LCA that meets ISO 14040 standards with a report evaluated by one or more third parties.

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3. How do you carry out a LCA?  

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There are 4 main steps.

3.1 Define the objective and scope of the study

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This is the first step in a life cycle assessment and should not be overlooked because it will determine what type of LCA is necessary, what granularity is expected in collecting data, results and their interpretation or even what impact indicators will be selected.

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• Objective of the study

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This is the reason why the company decides to carry out a LCA. A few examples:

• ecodesign
• comparison of several products or services
• comparison with the competition
• environmental labelling
• encourage subcontractors to improve their environmental performance

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From these objectives derives the field of study.

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• The field of study

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This is when we specify the type of LCA that will be carried out as well as the main characteristics and hypotheses that are chosen.

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• Do we start with a LCA “from cradle to grave” so on all the stages of the product's life cycle or a gate-to-gate LCA so a focus on a very specific process?
• What is the functional unit of the product or service that the LCA focuses on? This is fundamental in defining the field of study. The functional unit is the primary function, the service provided by the system under study.

Some examples of functional units: number of times a garment is worn for the LCA of this garment, write over a distance of 90km for the LCA of a pen, travel 15,000 km/year and for 20 years for the LCA of a car.

• Choice of environmental impact indicators and characterization methods.
• Methodological limitations.

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3.2 Life cycle inventory

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This is the most time-consuming step, the one that corresponds to data collection. The aim is to trace all the flows in the system under study: incoming and outgoing flows. Incoming flows are the flows of raw materials, energies or even water that occur at each stage of the life cycle. And outflows are emissions into the air, water, soil and waste, again at each stage.

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Here you will find a simplified diagram of the flows of the company Picture Organic Clothing, in the textile sector, for which we carried out a LCA.

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Some examples of flows to take into account in this LCA:

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• Composition of the garment: what raw material (cotton, polyester, wool, etc...) and the quantity of raw material (kg).
• Traceability: study of the countries in which the various phases of manufacturing are carried out (spinning, weaving, confection, etc.)
• Manufacturer data: energy used (coal, renewable electricity, etc...), quantity of energy consumed, chemical products, quantity of water used. If this specific data is not available, generic data found in databases can be used.
• Downstream: mode of transport used, distances, hypotheses of use, end of life.

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Here are some databases used:

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• general databases: Ecoinvent, Gabi, Impacts database
• sectoral databases: Acyvia, Agribalyse or AgriFootprint for the food industry; Kering or WALDB database for textiles; Worldsteel for steel.

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3.3 Impact Assessment

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The aim here is to convert the data collected into potential environmental impacts. These conversions are mostly done with software (SimaPro, Gabi, OpenLCA...).

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Very concretely, we multiply the flows collected by what are called characterization factors in order to obtain an environmental impact. For example, for the climate change impact indicator, the unit used is CO2 equivalent (CO2e). Thus, for all the greenhouse gases that will appear in the life cycle inventory, they will have to be converted into CO2e by associating them with a characterization factor. For methane, for example, we know that 1 ton of methane is equivalent to 28 tons of CO2. We will therefore multiply the methane fluxes by this factor of 28. As another example, for nitrous oxide, its global warming potential is 298 times higher than CO2. A factor of 298 is therefore associated with it.

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Which environmental impact indicators should you choose? Climate change? The depletion of the ozone layer? Eutrophication of fresh water? As we said before, the impact categories are selected according to the LCA objectives set at the 1st stage.

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Several options exist:

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• Most companies that carry out one or more initial LCA start by looking at all of the 15 impact indicators recommended by the European Commission. These potential impact indicators (also called midpoint) are the best known and the most accurate. It is then a question, for each indicator, of choosing the recommended characterization method. For example, you can rely on European recommendations, via the EPLCA (European Platform on Life Cycle Assessment). Several characterization methods may exist for the same indicator.
• There are also damage indicators (also called endpoints). They estimate the potential damage caused by the environmental impacts of the product under study. Indicators of damage are often found: human health, ecosystem or even resources. These indicators are fewer in number and can therefore make it easier to understand the results. However, they are less used because they are less accurate.
• For a LCA carried out as part of an environmental display, we will look at the indicators and characterization methods that are requested in the repository associated with this display (see above and the section dedicated to environmental labelling).

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3.4 Interpreting the results

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This is the final stage of LCA. Here it is validated that the results meet the objectives set at the beginning of the study.

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Below is an example of the anonymized results of a LCA that we conducted.

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Here, we decided to focus on two impact indicators: climate change and the eutrophication of fresh waters. The impact potential is set at 100%. This allows us to see where the main environmental impacts are found among the different phases of the life cycle. Here, the results are very clear since the bulk of the impact for both indicators is at the manufacturing level.

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It is entirely possible to go further and “zoom in” within a phase of the life cycle to be more precise on the origin of the impacts. We could do it in this example for manufacturing in order to see if the impact comes from a product, energy, a particular supplier, etc...

In the analysis and interpretation of the results, we can also work on standardizing the impacts. For example, we will look at the order of magnitude of the impact of the product compared to the impacts of an average European for one year.

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4. LCA and carbon footprint assessment: differences and complementarity

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The carbon footprint is the photograph, at a given moment, of all greenhouse gas (GHG) emissions related to company activities. Two major differences with LCA should be noted:

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• The scope of the study

The carbon footprint assessment analyzes the company's and value chain's GHG emissions and not of a product or service. Thus, in a carbon footprint analysis, we will take into account all the inputs, the impact of all the products manufactured by the company but also the travel of employees (home-work and professionals), food, fixed assets or even the energy used to heat the premises. Whereas the LCA focuses only on the data of the product(s) studied. Travel is not taken into account, neither is food, etc. In short, LCA allows you to zoom in on the precise impact of a system studied where the carbon footprint makes it possible to have a global vision of emissions related to the company's activity.

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• The impact indicator

And since we're talking about emissions, that's the other major difference between these two methodologies. The carbon footprint assessment makes it possible to assess a company's dependence on carbon. And carbon only. All of its GHG emissions and those in its value chain have been traced. With the carbon footprint assessment, we therefore focus on the impact of company activities on climate change. Where the iso compliant LCA looks at the impact of the product on climate change but also on numerous environmental indicators (eutrophication of fresh water, depletion of resources, air pollution, etc...).

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As a result, carbon footprint and LCA do not make it possible to achieve the same objectives. They are two different tools for different applications.

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However, while the applications of LCA and carbon assessment are different, these two methodologies are also complementary.

First, because by doing a LCA on one or more products, we obtain specific data on the impacts of these analyzed products. However, the impact of these products is included in the calculation of the company's carbon footprint. By having accurate data on the impact on climate change of its flagship products, those that are the most sold for example, the company then gains a lot in precision on its carbon footprint.

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And then, LCA and carbon footprint are complementary because both are obviously part of the company's climate strategy. Because it provides the company with very advanced levels of detail on GHG emissions and other environmental impacts of a product or service, LCA makes it possible to go even further than the carbon footprint. For example, it allows the company to engage in an eco-design approach and thus reduce the impact of its products, in particular on climate change. Another example, by comparing several products or alternatives, it also allows the company to make the most sober choices in terms of impact. Carbon footprint and LCA are therefore complementary and essential instruments for any company wishing to engage in an ambitious and effective strategy to reduce greenhouse gas emissions.

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