Life Cycle Assessment (LCA) is a vital tool for evaluating the environmental impacts of products across their value chain. This article breaks down fundamental concepts of LCA into four parts - including Goal & Scope, Functional Unit, Flowcharts, and Allocation. Whether you're new to LCA or seeking to deepen your understanding, this article provides valuable insights to help you navigate the complexities of environmental assessment. To do so, the following questions are covered:
What is the Goal & Scope phase in LCA?
What is the functional unit in an LCA?
What is the purpose of flowcharts in LCA?
What is allocation in LCA?
Don't feel like reading an article? Watch video tutorials on Goal & Scope, Functional Unit, Flowcharts, and Allocation instead!
What is the Goal & Scope phase of LCA?
The ISO 14040 standard outlines four phases in an LCA study - Goal & Scope phase, Life Cycle Inventory (LCI) phase, Life Cycle Impact Assessment (LCIA) phase, and the Interpretation phase. This article focuses mainly on the first phase. Check out our comprehensive guide to learn more about the other LCA phases and how they work together.
As the goal and scope phase initiates your LCA, it sets the foundation for the entire assessment, defining its purpose, boundaries, and intended outcomes. Understanding the intricacies of this phase is crucial for comprehensive and meaningful environmental analysis.
How to set the goal of an LCA?
Setting the goal of your LCA defines the purpose or “why” behind the assessment. Relevant questions to consider when setting the goal of your LCA include:
Why do you want to conduct an LCA?
What do you want to achieve?
What is the intended audience (i.e. to whom are the study results intended for?)
Do you want to compare the environmental performance between products or improvement scenarios?
Regarding the “why” behind your LCA, below are examples of potential motivators:
To comply with regulations (e.g. CSRD);
For internal insights (e.g. for research and product development, strategic decision-making, or ecodesign);
To make environmental claims (e.g. to market the positive environmental benefits of your product)
How to define the scope of an LCA?
Equally important to setting the goal is deciding the scope of the LCA, capturing “what” your assessment focuses on. This involves:
Establishing the functional unit to have a unit of measurement for the product under assessment;
Defining the product system and making a flowchart to identify the processes and inputs involved in the product’s lifecycle.
Outlining the system boundaries to ensure consistency and accuracy in the assessment.
Note - Flexibility and iteration: It's important to recognize that LCA is not a rigid process but an iterative one. As data and information are collected, adjustments to the scope may be necessary to align with the study's original goal.
Video Tutorial
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What is the functional unit in an LCA?
The functional unit is the unit of measurement for your product in your LCA. By aligning the functional unit with the study's goal and available data, you can effectively measure and analyze environmental impacts
A functional unit describes the function, or intended purpose, of the product in question. Focusing on the function of your product allows comparison across products that share the same function. Examples of functional units include:
X amount of dishes washed by a dishwasher in 20 minutes.
X m2 of wall painted.
Note - The functional unit and data collection: The functional unit sets the stage for data collection and analysis, ensuring consistency and comparability across assessments. As such, data must be collected following your functional unit. In some cases, this means collecting data per physical unit (per piece) first and then translating it to your defined functional unit.
With complex products, selecting the appropriate functional unit can be challenging. To help with this process, consider the following:
Comparability: To compare the environmental impact across products, the functional unit must be the same.
Scalability and multifunctionality: Consider a functional unit that is easily converted into other functions.
Data availability: Since input data must align with your functional unit, it saves you time to align the functional unit with your data management system’s unit. For example, if your data management system collects all data per kg of product, choose kg (or something that can easily be converted from kg) as a functional unit.
Are you still unsure about defining a functional unit? You can always begin creating your LCA by using a standard declared unit. Declared units are often used when an LCA does not cover the full life cycle of a product (i.e., cradle-to-gate). It can be expressed per “piece” of the product (i.e. a dishwasher), “kg”, “ton”, etc. You can then modify your model at a later stage.
Pro tip - Functional unit and environmental claims: If you are seeking to make environmental claims, you will likely follow certain Product Category Rules (PCRs), to get to a verified Environmental Product Declaration (EPD). PCRs tend to prescribe a specific functional unit for a certain product group, to enable comparison of these products.
Video tutorial
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What is the purpose of flowcharts in LCA?
In the goal and scope phase of an LCA, crafting a comprehensive flow chart is crucial in defining the scope - the boundaries and components of the product system. A flow chart offers a visual representation of the interconnected processes and inputs essential for understanding the environmental impact of a product or service.
Note - Relevance of flowcharts in LCA: Ultimately, the flow chart serves as the blueprint for constructing the LCA model in the software (i.e., Mobius and Helix). By visually depicting the product system and its components, the flow chart guides you in developing a comprehensive and accurate representation of the environmental impacts of your product.
How to create a flowchart?
The first step in creating a flow chart is to delineate the system boundaries, outlining what inputs and outputs are included in the assessment. This boundary sets the parameters for the analysis, distinguishing between what is considered part of the product system and what lies outside its scope. Refer to the questions in the Goal & Scope section to help you establish your system boundaries.
Once the system boundary is established, the flow chart maps out the various inputs, processes, and outputs involved in the product’s lifecycle. This includes but isn’t limited to, raw materials, transportation, manufacturing processes, and waste streams associated with the product (Figure 1).
Figure 1: A simplified example flowchart of the (potential) inputs, processes, and outputs involved in a product’s lifecycle.
Note - Highlight connections in flowcharts: Beyond simply listing components, the flowchart highlights the relationships and dependencies between different elements of the product system. It demonstrates how inputs are transformed into outputs through various processes, highlighting the interconnectivity and complexity of the system.
Pro tip - Missing information in your flowchart: If you do not know or have enough information on a certain area of your flowchart, it doesn’t mean you can omit it. Ignoring elements of your value chain leads to an incomplete LCA, ultimately underestimating your environmental impact.
By color coding your flowchart, you can also represent the quality of data available for all inputs/outputs or any other uncertainties you have. Similarly, when modeling your LCA, flowcharts act like a checklist to ensure you’ve included everything relevant within your product system and defined system boundaries.
Video tutorial
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What is allocation in LCA?
When a process yields multiple functions or co-products, allocation becomes relevant (Figure 2). Put differently, multifunctionality occurs when a process yields more than one valuable product. When this happens, there is a question of how to allocate the inputs (e.g., electricity) between the two (or more) products. Allocation solves the issue of multifunctionality in LCA. It involves splitting up the amounts of the individual inputs and outputs between the co-functions according to some allocation criterion (mass, physical properties, economic cost/value, or production amount). Allocation methods vary based on the LCA standard you’re following or the specific context. Whether allocating process inputs and utilities or managing multifunctional systems, you must carefully select allocation methods to ensure accuracy and transparency in the assessment.
Figure 2: A multifunctional system.
When to use allocation?
Below we outline two examples to help you understand when to employ allocation in your model:
Example 1: Allocation of process inputs and utilities measured over more than one product
Let’s say energy use data is not measured per single product, but, for example, over multiple of the same products for a certain time. How do you deal with this?
You need data for two values: 1) energy usage over a specific time period, and 2) production amount/weight over the same respective period. If these two variables are known, you must divide this energy usage over your products.
Different ways to divide the energy:
Based on the production amount
Based on the produced weight
In this example, allocating by production amount will suffice if you believe that the electricity consumption is relatively equally distributed over all products. If, however, you know that certain products require more electricity to be produced, it would be more accurate to use an alternative method to distribute the total electricity consumption over all products. If heavier products need more electricity, allocate the total electricity consumption based on the total produced weight to account for such variations.
Note - Data and allocation: Sometimes you are limited by the amount or quality of data. In the example above, if you don’t know the total produced weight (option 2), you will initially be ‘forced’ to use option 1. LCAs are an iterative process - it could be beneficial to go back to your supplier and attempt to get better data and refine your LCA later.
Example 2: Allocation of multifunctional systems
Let’s assume Figure 2 represents the baking process of two pies (two co-products): an apple pie (product A) and a pecan pie (product B). To allocate the impact related to the baking process, all inputs (energy or electricity) must be allocated over the two co-products. Consider allocating the baking based on the following criteria:
Based on mass (e.g. weight)
Based on physical properties (e.g. energy content)
Based on economic value
Table 1 presents the results calculated using each method - notice the variation in results.
Table 1: Impact results using different allocation methods
Product Name | Amount | Mass | Baking time [Energy Content ] | Economic Value |
Apple pie | 1 (50%) | 1.0 kg (39%) | 15 minutes (30%) | €2.40 (12%) |
Pecan pie | 1 (50%) | 1.56 kg (61%) | 35 minutes (70%) | €17.60 (88%) |
In this case, the difference between allocating based on mass versus allocating on economic value is 27 percentage points. A huge difference!
Caution - Selecting an allocation method: As the example above shows, different allocation methods can lead to very different results. How you should allocate the impact of your products depends on the standard you’re following. Where relevant, standards should be consulted ahead of selecting an allocation method.
If, however, no information is provided on allocation, typically some form of ‘physical allocation’ takes precedence to ‘economic allocation’. Allocation based on some physical attribute is more robust over time, while economic properties (prices & value) can change, which is undesirable for creating a future-proof LCA.
Video Tutorial
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Next Steps
As we conclude our exploration of LCA fundamentals, we've laid the groundwork for mastering this essential tool for environmental assessment. From setting clear goals and defining functional units to addressing multifunctionality through allocation, each concept contributes to achieving a more complete understanding of LCA. However, your LCA journey should not stop there! This article only explains some of the most challenging concepts in LCA - there is plenty more to learn and understand. Explore our other resources to learn more!