How to make an accessible life cycle hotspot analysis

Life cycle hotspot analysis can help confirm your intuition or lead you to new insights towards determining a robust sustainability strategy. This article gives a view on how to make detailed and complex hotspot analysis in life cycle assessment (LCA) clear to everyone involved.

Expertise And Methodology

One of the most important skills of any sustainability expert is translating their findings into a language that corporate social responsibility (CSR) managers understand. As a result, the quality of a hotspot analysis depends on the skills, knowledge and experience of the expert and the tools that he or she uses. Advocating for a consistent footprinting methodology carries the risk that people using the method will spend a lot of effort to produce the required tables and graphs and will not have as much time left to interpret the results and translate them into understandable conclusions. This article gives a view on how to make detailed and complex hotspot analysis in life cycle assessment (LCA) clear to everyone involved.

From Single Score To Individual Emissions

LCA results can be shown in many different levels of detail, which are useful in communication with different groups. The most aggregated version is the single score. The most detailed results show individual emissions and resource uses per process in the life cycle of the product. A spectrum of options exists between these extremes, to aggregate or disaggregate the different environmental themes, to group processes into life cycle stages, to show the individual emissions and resource uses or to add them up into a single metric.

Depending on your goals, it may be a good idea to start at a more aggregated level and then dive into the more interesting details. Several software tools are available to manage this complexity, with different levels of transparency, detail and flexibility. SimaPro is an excellent tool: it gives all the options that may be needed, while it is relatively easy to learn.

Top-down Approach

If you work from the top down, you can first check if all of the three aggregated damage category scores  (human health, ecosystems and resources) are relevant for the product you’re looking at. Then you can evaluate which of the individual environmental categories are relevant within each damage category. In most cases, the most important impact categories will be climate change, particulates, human toxicity, land use and fossil resources.

Then you need to group the processes in the product’s life cycle network into about five to eight stages to get a rough idea where the most important contributions to the selected impact categories come from. It is essential that everyone involved in the project agrees on this grouping and that everyone understands the group labels.

Grasping The Details

This level of detail may be sufficient for CSR managers. Technical experts will want to know more: which emissions and resource uses contribute most to the impact categories? Which life cycle phases or individual processes? This information may be difficult to show in graphs, but it is still important to be able to explain it to a manager when needed.

For most categories, the number of emissions and resource uses is manageable; the usual suspects are carbon dioxide, methane, nitrous oxide, sulphur dioxide, nitrogen oxides, particulates, natural gas, and hard coal. For the land use and human toxicity categories, the lists are longer and more variable. The impact sources are more likely to come from background processes far from the control of the product’s makers and to involve large uncertainties. This is why it is important to distinguish impacts occurring in the processes owned by the company, in processes owned by the direct suppliers and in the background processes.

Understanding And Prioritising The Main Findings

Hotspot analysis in LCA is not just about showing the relative contributions of life cycle stages to the different environmental indicators. It is also about understanding the individual emissions and resource uses behind the scores, their level of uncertainty, and the level of control the company has over those emissions and resource uses. Of course, all environmental impacts are relevant in principle, but we need to prioritise and start reducing large impacts where we can.

At PRé, we are convinced that sustainability decisions should be based on scientifically sound analysis. We help experts and CSR managers work together on the best sustainability strategy through sharing our knowledge and developing specialised software tools. Please contact me if you want to exchange ideas or questions.

Tommie Ponsioen

Tommie worked for PRé as a Technical Consultant from 2012 until 2015. As a part of the Consultancy Team, he worked with databases and methods. Tommie collaborated in projects such as Prosuite and improving the ReCiPe method.

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