5.1 Introduction
5.2 Pathways Toward Circular Design
5.2.1 The CE Approach Offers a Paradigm Shift
5.2.2 Different Frameworks for CE Operationalization: Slowing, Closing, Narrowing, and R-Strategies
5.2.3 Three Implications for Design
5.2.3.1 First Implication: A Change in Product Design
5.2.3.2 Second Implication: A Change in Service Design
5.2.3.3 A Third Implication: A Change in User Behavior
5.2.4 Implementation Challenges
5.3 Expert Conversation on Sustainability in Product Development
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Zipse: Perhaps the most important ingredient in purchasing behavior is brand. We at BMW say that having a strong brand is very important—a brand with an innovative image, because the world very much links innovation with sustainability. We are convinced that most solutions for sustainable products come from innovation. Therefore, the impact of sustainability on brand image is the most important impact we have here.
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Wartzack: What does this mean for product design?
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Zipse: In addition to regulatory compliance, consumer behavior, and societal changes, it is about creating a brand image that remains attractive to current and future customers. We make sustainability one of the most important aspects of our product development because when it comes to products, you have to live up to what you say. You can talk a lot about what you want to achieve in the future or what your goals are. In product development, however, you have to put your words into action. People can experience your product, they can touch it, and of course they can drive it. People believe in your product strategy when they can see it.
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Wartzack: In product development, we talk about Design for X, where X stands for recyclability, sustainability, use, transport, or production. Design for sustainability is very important, especially for the younger generation. We talk about Fridays for Future and CO2-neutral production. However, the younger generation is not the typical BMW customer. What is your view on that?
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Zipse: We have customers of all ages. They start at 25—these are really our new car buyers—and the average age is somewhere around 50. Across all age groups, sustainability becomes one of the most important factors in purchasing behavior. In other words, if your brand is not perceived as sustainable—especially a premium brand like BMW—you are out of the game. You are simply no longer attractive in this market. Sustainability is at the center of political movements around the world, and all stakeholders are realizing that innovation and sustainability are key.
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Wartzack: Yes, I absolutely agree. It is important to make cars for all ages. Another thing that is changing: When we were young, it was important to own a car and to be free. The younger generation considers having a car very important when you need it—a connected car that is environmentally friendly.
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Zipse: When we talk about product development, at the end of the day, it is about materials in the car. How do you see the use of materials in the car changing from, let’s say, the old world, where cost and functionality were at the heart of product development, to a more sustainable approach?
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Wartzack: There are many new materials, even natural materials like hemp, sisal, or flax. However, many design challenges arise with these new types of materials. For example, the maximum tensile stress for glass fiber is about 1000 megapascals, whereas for hemp fiber, it is 250 megapascals. Material engineers and product designers have to take this into account and design in a different way.
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Zipse: I can relate to that. I think our engineering, innovation, and design departments face similar challenges with new natural materials. So, the question is: How do you overcome the design challenges associated with using natural materials?
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Wartzack: With natural materials, you need reliable data. Why don’t engineers like to design with wood, for example? Because it is very difficult to predict the behavior of wood, given its irregularities, such as knotholes. That is why design with natural materials is very difficult for the designer. But we have to differentiate. On the one hand, there are parts of the car in the main crash load path, where I would still use steel and aluminum, which are very recyclable. On the other hand, there are other parts, such as door systems or bulkheads, where biomaterials and biocomposites could be used. You can find concept cars in which the entire outer shell body is made of biocomposite materials. The key is to use the right material in the right place.
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Zipse: Weight has its ups and downs. When we were designing an electric car 10 years ago, we thought weight was the most important thing. Therefore, we used carbon fiber for the shell of the i3. We built the whole supply chain around carbon fiber, with a huge effort to make the car lighter. Making cars lighter is still a priority, but at the same time, other performance factors, such as aerodynamics, matter from a sustainability perspective. What is your view on weight reduction and lightweight materials?
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Wartzack: Weight reduction through the use of high-quality lightweight materials is still an important factor, especially in the top-of-the-range segment, for reasons of driving dynamics. The BMW i3 impresses with its complete body made of carbon fiber-reinforced plastics, which was designed using very intensive dimensioning tools and computer-aided engineering tools. There is no doubt that designing with hybrid materials has huge advantages. However, their use requires new engineering skills and new recycling concepts. A car is a mixture of different materials, each put in the right place, depending on crash load paths and price.
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Wartzack: The interior of the i3 featured a lot of natural materials. This is very good for the user’s perception. When you touch the surface, it feels warm. Are natural materials an important part of your future generation of cars?
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Zipse: Natural materials are important, but we are also researching and developing future natural materials, such as synthetic leather, with materials that can eventually substitute crude oil. And we want to substitute natural leather in the end. Weight plays a role, too. By reducing weight, the car consumes less energy over its life cycle. However, we are increasingly seeing a secondary effect: if the car is lighter, less material is needed for its manufacture. If you look at the world today, it is all about resource efficiency. Today, humanity extracts around 100 billion tons of raw materials from the planet each year.
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Wartzack: That seems to be the inconvenient truth.
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Zipse: You can argue whether this is too much. Perhaps it is. It has already had the effect of steadily increasing the cost of extracting natural resources from the earth. So, in addition to weight reduction, a secondary approach is to use as little material as possible because raw materials are becoming more and more expensive. Look at palladium or rhodium these days. Of course, the COVID-19 pandemic was also a reason for the increase in raw material prices. But you are at risk: If you use too much material, your base cost will increase.
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Wartzack: So what would be the right strategy to balance cost and weight reduction?
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Zipse: We are very committed to reducing material and the base cost at the same time. We have implemented several methods to reduce weight. For example, we use bionic design and additive manufacturing technologies to build parts. Every kilogram of weight reduction in the car has another secondary effect: If the car is lighter, you can use smaller brakes or smaller battery packs to cover the same distance. That is why, after improving the car’s aerodynamics, weight reduction is one of the most important areas of progress today. What do you think?
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Wartzack: Yes, I absolutely agree. Sustainability means saving material and reducing weight. We can do a lot with the right dimensioning with the intensive use of dimensioning tools, for example. So, all in all, I think the product designers have to do their best to find a way to achieve these two goals.
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Zipse: Do you think, when you choose materials, that a sustainable material choice has to look and feel sustainable? Is it a matter of haptics and quality? Is it enough that it is sustainably produced with a very small carbon footprint? Will customers pay extra money for sustainable features?
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Wartzack: The appearance of a car is a very complex issue. On the one hand, the younger generations are striking on Fridays for Future, and society is demanding CO2-neutral production. The world is waking up. On the other hand, everyone wants to buy an iPhone. User perception and attractiveness are very important for Apple products. Even older people buy iPhones despite the availability of mobile phones designed specifically for that age group. It’s all about how much people love using your product. They like the design, the interaction, and the experience. Customers want to feel emotional about their products, and the integration of sustainable materials, the implementation of sustainable production, and sustainable supply chains are key arguments.
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Zipse: You mentioned that the i3’s interior materials feel warm. About 10 years ago, the interior had to be as cold as possible. Lots of chrome, lots of brushed metal, and so on—it was all over the place—black panels everywhere. That is changing. If you look at the iX or the new i7, it is designed more like a private lounge. There are almost no cold materials in your home anymore. Black leather is used less, and chrome is used less. Instead, we see warm, earthy materials. This also carries over to the interior of the car. It has a lot to do with the choice of materials. Electric cars are perceived as a space where you can withdraw from the outside world—especially because of the silent driving characteristics. People want to feel more at home. This has a big influence on the materials we choose.
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Wartzack: And what do you think—how eco-friendly could a BMW look in the future?
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Zipse: We don’t think it has to look like you are missing anything. It has to look like … You mentioned the iPhone. The iPhone is absolutely first class in terms of quality, and I think that will never go away. It is more the story you tell about how this product is made. It always has to look high quality. What you cannot do is neglect the quality of your product and claim it is sustainable. That will not work. There is no excuse for that. It is more a matter of what is perceived as aesthetically superior.
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Wartzack: I absolutely agree with you about the quality aspect. But what is then perceived as superior by consumers today?
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Zipse: Natural materials are perceived as aesthetic and progressive. You have to supply them at a very high level of quality. Then, the perception of quality comes naturally because the product is warm by its nature. But still, natural materials do not have to look natural. We are now on a level of interpretation that allows a lot more. You no longer see if it is based on natural or synthetic raw materials. It is all about design.
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Wartzack: That is certainly the case with natural materials. They are sustainable and often recyclable or compostable, but what about synthetic materials? Especially in the interior design, components are made up of several layers, which limits their recyclability.
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Zipse: Good point. Another important aspect is mono materials. My favorite example is a seat cover. It consists of a surface component, and material underneath, and the foam underneath is glued to another piece of foam. But they are two different materials. This makes them very difficult to recycle because they cannot be separated. What we are trying to do now with our next architecture is to use more mono materials. Mono materials are easy to recycle. These are things that we haven’t thought about to this extent before. But the transition is quite easy: You have to start thinking from the recycling process, not just from the product design process. In the end, you may even find that you will have a better cost base.
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Wartzack: I remember the hype about recycling in the 1990s. I visited a pilot recycling plant in Munich and found it very impressive. Before that, I remember that some parts in the BMW dashboard were made out of polypropylene foam, PVC, and metal parts—a complete mixture of materials. So, a lot of Design for Recycling approaches and tools were developed in the 90s. How established are these approaches that have been developed since the 1990s in the BMW production environment today?
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Zipse: In our private lives, we all know what a green dot is (in German “Grüner Punkt”—a sign for waste collection and recycling systems). Everyone knows that. What kind of material goes into which channel is regulated. Paper goes in this channel, mixed materials go in this channel, glass goes in that channel. The car industry is very big, but it has a highly diverse global regulatory landscape for the recycling process—the afterlife of the car. We expect some new regulations soon in the EU, where the Battery Regulation puts into place new objectives (e.g., for the recycled content). You have to think 10 years ahead about what will happen to our cars if a new policy is based on the upcoming revision of the End-of-Life vehicle directive. What happens to the car after the use phase? You can already start thinking about how to design your car if suddenly a policy is in place that requires that you recycle the car and extract all the raw materials. This immediately leads to the use of secondary materials. However, the quality of secondary materials today is not sufficient.
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Wartzack: Why is that?
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Zipse: Because they cannot be completely separated in the recycling process. If you could separate them the way we do with household waste in our daily lives, it would not be a problem. The recycled product would be as good as the product in the first cycle. Separating materials would be easy if you built separation into your product development strategy from the start. To do it in retrospect is extremely difficult. How can we increase the amount of secondary materials? You know the term “cradle to grave,” but in the future, it should actually be “cradle to cradle.” The car goes through its life cycle. At the end of the day, it is dismantled and recycled, and it is again part of a new car. A “cradle to cradle” system is the actual target we are aiming for. As a product design researcher, what are your suggestions on how to approach design for circularity?
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Wartzack: The designer has to design in such a way that the materials can be easily recycled—by implementing detachable joints, for example. Transparency of information is also key. You need to know what material composition is behind some plastic labels because that can also be very confusing if they are not labeled correctly. The OEM should be in charge of recycling because they know their car best and can plan recycling strategies at the concept stage. The manufacturer knows best which components can be given a second life. BMW is already doing it for battery packs at its Leipzig plant, where used battery modules are used as stationary energy storage.
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Zipse: Yes, we started using spent battery packs as stationary energy storage in 2017. So far, we are satisfied with the results of this pioneering project.
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Wartzack: That’s great to hear. A second life for cars is also a very sustainable approach and a good thing. If a car is used for 10–15 years in Germany today, it will then be used for another 10–20 years in Africa or elsewhere. This life cycle is quite common, as long as it is in line with existing recycling regulations. At first glance, this path does not necessarily seem to go against sustainability, but it does not bring secondary materials back into the cycle. I can imagine that ownership after the use phase is very difficult to control, and this also applies to effective recycling strategies when they are not mandated by legislation.
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Zipse: I agree. Speaking of Africa and its resources, let us return to the use of natural materials. They have the best recycling properties, but at the same time, they are difficult to use because their properties are not so consistent. You mentioned the use of wood. What do you think about the product properties of natural materials and their recyclability?
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Wartzack: It is a big challenge. Using natural materials, such as natural fibers (e.g., hemp, flax, and sisal), wood, or leather, is a good thing, but it is challenging and makes life very complicated for the designer. That is clear. You need reliable data to make sound predictions about the mechanical properties of the materials. For example, performing your own tensile tests and simulations and conducting numerous cycles of validation, rather than blindly trusting the data sheets provided by the supplier, can be helpful. This is the basis for dimensioning products and even components. It is a lot of effort, but it pays off in the end. How do you deal with these challenges in BMW’s product design department?
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Zipse: We still need to learn more about how to use natural materials. One field of research and development (R&D) that needs to grow is simulation methodology—how do I simulate natural materials? That should even be a new field of research. As you said, it is worth the effort. Clean natural materials can go back into the natural cycle, while all other materials must be recycled for reuse, which is a task in itself.
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Wartzack: It is actually an emerging field of research. With 100 billion tons of new raw materials to be extracted, the use of natural materials will not be the only answer, as their application in car design is limited.
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Zipse: Well, you are right. And there are many other issues to bear in mind, such as the loss of biodiversity due to the additional land use needed to grow these amounts of materials if we use our current technologies. I learned a lot when I read Bill Gates’s book because he put into perspective what we actually want to achieve by the year 2050. A lot of the technologies don’t exist today; therefore, we have to conduct a lot of research to find the right technologies. None of the technologies that exist today are capable of solving our climate problem. I found that quite evident. Similarly, many aspects of car design still need to be rethought and require new technological developments.
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Wartzack: To address these global challenges, we need more comprehensive approaches, such as Life Cycle Assessment (LCA). A lot can be done, but you need very accurate data throughout the entire value chain. Building up a sustainable process chain is quite tedious: you have to know where and how materials are extracted, how they are transported to the plant, and so on. Let me take the simple example of wine. What kind of wine would you prefer? For sustainability reasons, a wine from Australia or a wine from Italy? Most people would say, a wine from Italy, obviously. But imagine that the wine from Australia comes in large batches by ship. It could be that, at the end of the day, the wine has a better carbon footprint than the wine from Italy, which comes in small batches. Accuracy of data is key, so a lot of data analysis needs to be conducted to precisely measure and compare life cycles. The peak of recyclability and LCA approaches was in the 1990s, but today, we have completely new possibilities with AI. This is an emerging area of research.
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Zipse: Wine is a very good example. Normally, one would assume that the Italian wine—or even better, a German wine—would have the best LCA because of the short transport distance. But this evidence is too simple. You learn from your mistakes: Ten years ago, we would have assumed that ride hailing was clearly good for the climate in cities.
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Wartzack: And it is not?
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Zipse: It actually turned out not to be the case, because first of all, with ride hailing, a lot of people switched from public transport to private transport, and consequently the number of kilometers driven increased. Traffic jams—our best example is San Francisco—have actually increased because of ride hailing. The assumption that this had only a positive environmental impact was incorrect. This is where we really have to understand and think all these things through to the end, to understand the whole life cycle effect. The life cycle effect will become a relevant decision factor in the future. Anything you do has a life cycle effect. Only by regulation will you see that life cycle effects become transparent and will be decisive.
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Wartzack: There needs to be a regulatory effort to make lifecycle costs transparent. This becomes evident in the case of natural materials, which are sometimes more expensive than conventional materials because not all life cycle costs are captured.
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Zipse: We would if the entire life cycle effect was taken into account. At the end of the day, our cost base has to be in line with customer behavior. Customers today are extremely cost sensitive, even in the premium segment. This is not a one-size-fits-all answer, but if the market and consumers recognized a full life cycle effect, we would consider spending more money on it. We did this with carbon fiber, which was mainly produced using renewable energy sources in the i3. Of course, the carbon fiber structure was much more expensive than a normal steel structure. But we are open to making these bets for the future if we see evidence that it will have an overall life cycle effect that is acknowledged.
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Zipse: I think we have learned a lot about the use of carbon fiber. It is not necessarily scalable to very high volumes. Electromobility is now going to be a mass market segment, so an entire structure made of carbon fiber does not seem appropriate. However, you can see in the iX that the side frame is made from carbon fiber. We use it in certain structures where it makes sense, but there will not be another full carbon-fiber car body in the next few years. Product development is really one of our core competencies, and there are many exciting technological developments in the pipeline for the future.