Defining Your LCA Goal, Scope and Boundaries

A well-defined goal and scope ensures your Life Cycle Assessment (LCA) results are relevant, accurate, and actionable. This is especially important in XYCLE, where your scope selection determines both the data requirements and the type of results you will see. Without a clear goal and scope, it is easy to misinterpret results or make decisions based on incomplete information.

Beginner’s Guide: What is the goal?

The purpose of the study is described as part of the goal, and it outlines the following:

Target audience
Intended application of the results
Motivation for carrying out the study
Stating who the commissioner of the study is, and other stakeholders
Explicitly mentioning whether the results of the LCA study are intended to be disclosed to the public

This stage is important as it informs the direction of the later phases of the LCA as well as the scope and boundaries set in XYCLE.

Beginner’s Guide: What scope means

The scope of an LCA is like the frame of a photograph. It decides what is inside the picture and what is left out. Different scope types include:

Cradle-to-grave: covers the entire life of a product, from raw material extraction, processing and production, through to its use and disposal
Cradle-to-gate: includes everything up to the product leaving the factory or another point in the supply chain, but not the use or disposal stages
Gate-to-gate: focuses on a single stage in the production process

Choosing the right scope depends on the purpose of the study, the data you have available, and the intended audience for your results.

Beginner’s Guide: Deciding a Functional Unit

As part of a complete LCA a functional unit needs to be defined for a product of process. A functional unit is a quantified description of the function of a product that serves as the reference basis for all calculations in an impact assessment.

This unit of measurement can vary depending on the context and the aspect of the product's performance or use being assessed. It can take into account parameters such as:

Quantitative measures (e.g., mass, volume, energy content)
Qualitative measures (e.g., purity, grade)
Temporal aspects (e.g., duration of use, operational time)
Performance requirements

A well-defined functional unit enables the comparison of the environmental performance of different products or systems that serve a similar function.

Advanced Detail: Foreground and background systems

In professional LCA practice, you also need to understand the difference between foreground and background systems:

Foreground processes are the ones you directly control or can strongly influence, such as your own manufacturing operations.
Background processes are external activities that support your operations, such as electricity generation or the production of materials you purchase.

In XYCLE, you can specify which processes belong to each category. This is particularly important for suppliers, whose scope may be limited to the processes they operate directly, while manufacturers may require a full system view.

Advanced Detail: Product Multifunctionality

In the context of LCA, multifunctionality refers to situations where:

a process has multiple outputs (co-products)
a product serve multiple functions

When a process produces more than one product, the environmental impacts need to be divided fairly between them to avoid giving a misleading picture. Without this, one product might seem better or worse for the environment than it really is.

The scope should also explain how the impacts will be shared among all the co-products from the system. Multifunctionality may not always be relevant (if there is a lone product with no coproducts) and needs to be assessed as part of the scope of the study.

As such, the three main approaches to resolving this multifunctionality include:

System expansion (by substitution) - assumes that a co-product from a process can substitute for its commercial equivalent, thereby avoiding the emissions associated with the production of that commercial equivalent.
Mass Allocation (using a physical parameter, such as mass) - distributes environmental impacts based on the physical mass of each co-product generated during a process
Economic Allocation (using an alternative parameter, economic value) - distributes environmental impacts based on the economic value of each co-product generated during a process

The appropriate resolution for multifunctionality should be decided based on the product or process in the study, with fair reasoning.

In XYCLE: Applying scope and boundary decisions

In XYCLE, your scope and boundaries are expressed through the way you set up your model. This includes:

Choosing which processes to include and how they link together
Deciding whether to model the entire life cycle or focus on a specific stage
Selecting datasets for foreground and background processes that align with your intended scope
System Expansion or allocation based on mass or economic value built into the model

By making these decisions before and during model setup, you ensure that your results are consistent with the goals of your assessment.

Next Steps Checklist

Define the goal of the study, what is the LCA intended for?
Decide whether your model will represent the full life cycle or a specific stage
List the processes you want to include and note any that will be excluded
Identify a relevant, measurable functional unit for the study
Identify whether multifunctionality needs to be considered
Consider which datasets will best represent your background processes
Begin building your model in XYCLE with these scope decisions in mind