Vehicle LCA encompasses all phases of the product cycle, from raw material extraction to end of life recycling and disposal.
Life Cycle Assessment (LCA) continues to gain traction as the preferred method for assessing the environmental impacts of a product, and we are seeing more and more automotive LCA studies, and claims or conclusions based on LCA, being published. Here are five things to look for in an automotive LCA study. This is not an exhaustive list – there are many more things that need to be considered when conducting an LCA (the international standard that lays out requirements and guidelines for LCA, ISO 14044, lists 14). For a detailed look at LCA, I recommend Environmental Life Cycle Assessment, an excellent textbook published by the American Center for Life Cycle Assessment (ACLCA).
1. Is the study comparing “apples to apples”?
This can sometimes be a bit of a challenge in an automotive LCA, as cars are complex products made up of many systems and sub-systems, with supply chains that reach around the world. It is easy to lose sight of apparently subtle differences.
One such difference arises in material comparisons of an existing product and one at the design stage. Before making choices about which material has the lower impact, it is important to decide if this is a fair comparison. Have both designs been fully optimized? Does the theoretical design meet all the requirements (e.g. crash, NVH) of an existing design that has gone through all the additional steps necessary to get to production?
Functional equivalence is another important factor to consider. For example, it would be inappropriate to compare the “body” of a vehicle with a body-on-frame design with the “body” of a vehicle with a unibody design. Though both systems are casually referred to as the “body”, their functional requirements are very different. Similarly, when comparing an assembly of stamped parts to a single casting, it is important to include all the stamped parts that are required to meet the same functional performance as the cast part.
2. Has the best and most appropriate data been used?
As with any assessment tool, data is key, and there are many factors that can help determine which is the most appropriate to be used in a particular study. There are ten of these factors listed in ISO 14044, but I will only talk about three of them here. If you want more detail, Guidance on Data Quality Assessment for Life Cycle Inventory Data, published by USEPA’s National Risk Management Research Laboratory is a great resource.
Temporal scope – the temporal scope of the data describes when the data was collected, as well as the time period to which the data applies. An often-used rule of thumb is that the data used for the study should be no more than five years old. The goal is to use either data that reflects the time period when the product under study was actually produced or the most recent data that captures the current state of the art (these may of course be the same thing).
Geographical scope – the geographical scope of the data describes the location to which the data applies. This is critical, as the same process may have a very different impact profile in different locations. For example, primary aluminium made largely using electricity from hydropower in Canada will have a much different impact from primary aluminium made in China, where the electricity used comes almost entirely from coal. With automakers increasingly developing global platforms (i.e. using the same parts all over the world, as often as possible), it is important to consider how the results of an LCA might change if a product is produced in a region other than the one studied. The same is true when considering where a product is used. For example, the differences in electricity generation in Canada and China will greatly affect the impact of charging an electric vehicle.
Technological scope – the technological scope of the data describes the technology to which the data applies. Often the same product can be made from a variety of production pathways. Much like production in different regions, production via different pathways can result in much different impacts. An example of this is primary magnesium production. Magnesium produced via the Pidgeon process (a declining, but still-used method) can have a global warming impact more than 1.5 times higher than magnesium produced via the electrolytic method.
3. How sensitive are the results to changes in the choices made?
Because LCA involves choices about things like data and functional requirements (as well as a host of other parameter choices), it is important to understand what happens to the results if different choices are made or underlying conditions change. Inclusion of a sensitivity analysis of this kind allows us to evaluate the results of an LCA and look for areas that might require further study, perhaps by looking for more precise data. It could also affect decisions we might make based on the results. If the results of a study are very sensitive to the location in which the materials are made, we want to evaluate this if we are considering making the product in many different places.
4. What is the fundamental approach taken?
ISO 14040, which lays out the principles and framework for LCA, describes two fundamental approaches to LCA:
- one which assigns elementary flows and potential environmental impacts to a specific product system typically as an account of the history of the product, and
- one which studies the environmental consequences of possible (future) changes between alternative product systems.
It is important to consider which approach was used, and what the chosen approach means in terms of interpreting the results. In a very basic sense, the key lies in the words “history” and “future”. A study that considers the historical impact of a product (i.e. the impact of any product that has already been made) tells us about the impact of that particular product, but may be of limited use in making decisions about what the impact of that same product may be in the future. Studies of the potential future impact of a product, while necessary for decision making, are fraught with all the perils of predicting the future. Both approaches are valuable, and it is important to understand which approach was taken in order to make decisions about how to use the results of the study. The ILCD Handbook: General guide for Life Cycle Assessment, published by the Joint Research Center of the European Commission, provides guidance on when to use each approach in assessing the technological representativeness of LCI data.
5. How broadly can I apply the results?
It is often tempting to apply the results of a study more broadly than is justified. Given all the factors listed above (as well as the many others not included), it is critical that careful consideration be given when making decisions based on the results of automotive LCA studies in order to make sure that the scope of the study is in alignment with the scope of the decision. It is clearly inappropriate to make global decisions based on local studies, or to make future decisions based solely on past conditions. LCA is a valuable, well-developed tool for assessing environmental impacts, but we must be careful to use it appropriately.
The UCSB Automotive Energy and GHG Model, developed on behalf of WorldAutoSteel, is a publicly available, peer-reviewed tool for the assessment of automotive emissions on a life cycle basis. Version 5 of the UCSB Model can be downloaded for free at www.worldautosteel.org. At the UCSB Model page, you’ll find a video workshop at the end featuring Russ Balzer explaining the contents of the Model. A user guide is also available for download.
Does the subject of Life Cycle Assessment confuse you or would you like to learn more? There is a great free online course at our sister organization steeluniversity, “Introduction to LCA”, taught by Dr. Matthias Finkbeiner, head of the department of Sustainability Engineering at Technical University of Berlin, who introduces LCA methodology to analyse the environmental burdens of product and service systems. The course is fun and interactive, and you can finish it at your own pace.
Russ Balzer, LCACP, Technical Director, WorldAutoSteel and Phoenix Group
Russ Balzer is the LCA Technical Director at WorldAutoSteel and Phoenix Group. As Technical Director, Russ manages a variety of engineering projects, and has tactical and strategic responsibilities in WorldAutoSteel’s efforts to use and promote Life Cycle Assessment (LCA). Russ recently achieved LCACP certification and was recognized for his work in the field of LCA with the ACLCA’s Rising Star Award.