New research – What is a car actually made of?

“Felipe’s work is truly unique. Thanks to the collaboration between Volvo Cars and Chalmers, he has been able to conduct life cycle assessments at a level of detail that was previously impossible. This gives us a new understanding of the complexity and environmental performance of cars that goes far beyond exhaust emissions and electrification, taking into account all material choices and laying the groundwork for the industry to address future challenges related to resource use and the circular economy,” says Björn Sandén, examiner and Professor of Innovation and Sustainability at the Division of Environmental Systems Analysis at Chalmers.

“What surprised me most was that a car can be highly complex from a resource perspective even though just a few materials dominate by weight. Behind all the steel and aluminium lies a kind of hidden periodic table containing more than 50 other metals and metalloids. Sometimes they are present in quantities of just a few grams or even less, yet they can still be crucial to the car’s function and dominate its profile in terms of long-term resource scarcity,” says Felipe B. Oliveira, who completed his doctorate at Chalmers with the thesis Inventory Resolution and the Interpretive Scope of Life Cycle Assessment – Environmental and Resource Profiles of Passenger Cars. He conducted his research as an industrial PhD student at Volvo Cars and a doctoral student at the Division of Environmental Systems Analysis at Chalmers.

 In the most highly equipped car included in the study, 55 different metals and metalloids were identified. Iron and aluminium together accounted for around 90 per cent of the total mass of metals, while many of the other elements were present only in very small quantities.

These elements also serve different functions in the car. Copper is found in more than 700 components, mainly in wiring, while molybdenum, niobium and vanadium are used as alloying elements in high-strength steels. Even a few grams of gold can have a significant impact when the car’s contribution to long-term resource scarcity is calculated.

Your research shows that the level of detail in material data affects what a life cycle assessment can tell us. Why does this matter, and what do we risk overlooking when we use less detailed data?

“A life cycle assessment can only capture what is represented in its data. If, for example, materials are grouped into broad categories, you can still get a reasonable picture of impacts such as climate change, but it is easy to lose sight of the small amounts of gold, molybdenum, palladium and other elements that are important from a resource perspective. The result is not simply less precise; the analysis also has a narrower scope. The level of detail determines not only how accurate the results are, but also which questions the analysis can answer.”

Felipe B. Oliveira has also compared the material-related environmental and resource profiles of cars from the 2012, 2016, 2020 and 2024 model years. Over this period, the weight of the parts of the car included in the study increased by around 20 per cent, while the climate impact from material production increased by around 42 per cent. One important reason was the increased use of aluminium.
At the same time, long-term resource scarcity changed considerably less. Behind the overall figure, however, there were substantial shifts in which materials accounted for the impact.

How do you interpret this development, and what do you think is the most important lesson to take from it?

“It shows that the picture becomes more nuanced when we consider several perspectives at the same time. We found that the climate impact from material production increased significantly, partly because of the increased use of aluminium. At the same time, long-term resource scarcity changed considerably less, although the materials dominating the impact shifted over time. The most important lesson is that different sustainability challenges do not always follow the same trajectory. If we want to understand the consequences of future material choices, we therefore need to analyse both environmental and resource aspects rather than relying on a single indicator.”

You conducted your research both at Chalmers and within Volvo Cars. What did that combination make possible – and how can the results be applied in practice in the automotive industry?

“At Environmental Systems Analysis, I was able to develop and critically evaluate the method, while the industry collaboration gave us access to specific material data from real vehicles. That access was crucial. Without such data, it would not have been possible to move from general assumptions about a typical car to analysing how actual material choices and their environmental and resource implications change between vehicle generations. The results can provide the automotive industry with a better basis for prioritising measures in areas such as design, material selection, recycling and supply chains.”