Circular economy with Yvonne van der Meer
Yvonne van der Meer talks about the hidden considerations of overlooked bio-based products.
Can you describe the group’s work?
We look at the whole value chain of bio-based materials, from resources to how you produce the materials and applications. My group is focusing on sustainability assessment, for example, if we switched from a fossil-based to a bio-based material, would that mean we have a more sustainable material? This is not an automatic yes, because shifts in the resources used to make materials creates other impacts.
For example, we joined a project in Canada looking at the timber transport chain, and in this case the client used trucks. Travel distances can be very long and go into the US. Timber has an advantage in that the natural material captures CO₂, so in principle you have a CO₂ negative product. But the travel distances and the machining involved to shape the wood affect the whole supply chain’s carbon footprint. We considered, if you can add two small pieces per truck to the next train station or river and then use train or ship transport over a long track, then you can reduce the greenhouse gas emissions. We made a delivery decision support model for the company so it could find the optimal balance between the three elements of time, cost and greenhouse gas emissions.
So we can’t just switch between materials?
It’s not one expertise. From a business perspective, if you want to switch from fossil-based to bio-based, you will meet new partners and change your value chain to resources you are not familiar with. That creates new opportunities, but you also have to bridge new borders between sectors that have not worked together in the past. In our region, we bring together people from agriculture and horticulture with the chemical industry. They speak different languages and have different ways of doing business, but if you want to link the two, you need to consider, for instance, the seasonality of biomass where you do not have the same supply the whole year. The chemical industry is not used to working with a supply that is not stable, so you need to manage that.
From a research perspective, I don’t look at the resource only. If you want to change the resource, many more things are going to change. One of the current issues with materials everybody’s talking about is ‘plastic soup’ – plastics in the ocean – and the problems of that. We work on bioplastics, but that doesn’t mean they have a better end-of-life than the current fossil-based plastics. Lots of people make bioplastics that have the same properties as fossil plastics, only they are made from a different resource. So the problem is even bigger than we thought it would be.
Sometimes, switching to bio-based is not the solution. That’s why we have projects on the more circular value chains, where you try to use plastic waste from some company or the collection industry to re-use materials that make plastics. Then you reduce two things at the same time – fossil resources and the waste that’s currently generated from the plastics industry.
Can you share an example of this?
A company in the Netherlands makes parts of its shoes from recycled material, but also makes the shoe in such a way that it can be disassembled after use very easily. Here, you have to look at how shoes are glued together so they can be disassembled after use, and that the shoe can be recycled afterwards. The shoe is made of recycled materials and it has a kind of materials ‘passport’, so you know what polymers have been used.
This is one of the current issues with the circular economy – you collect plastics but you have to know what kind of polymers are in there. You also do not want a mix of polymers in your material. If you have these, they must be easily separated otherwise the quality will go down when you use them next time. These products are made in such a way that after use, you can easily separate the polymers and put them into different recycling streams to make high-quality products again.
What are the next steps for you?
One of the things we want to investigate is what are the determining factors for circularity to be sustainable? For instance, with the shoe company, we are going to calculate for them what would be reasonable transport distances to still have low environmental impacts with all the collection of materials and reuse for new products.
One thing we would like to look into is biodegradation of plastics. Some bio-based materials are biodegradable, but research has found these do not always fully decompose, but rather degrade to microplastics. These are the things we try to avoid in our current environment. We would like to look into fully biodegradable plastics to see if they have environmental advantages in certain applications.
You have to look for applications where these ideas would be sound to implement them. We think that for food packaging this would be an option, that at some point when the food is not good anymore, you can throw the food and packaging in the compost. Currently in the plastic stream, food waste contaminates the materials they are carried in. I would like to investigate this further.
Another is waste products from agriculture. We are currently starting a project to look into many different biomass resources to see what would be optimal scenarios for the bio-based economy, in particular for materials. Which resources are to be preferred over fossil-based? If you want to switch from fossil-based, which ones are the best to use? And at what scale? Maybe there is an optimal scale for using resources in a certain area and not transporting them all over the globe like we currently do.
How is agriculture impacted?
If you shift to sugar cane as a resource, then you have to take into account the water, pesticides and fertilisers used to grow the plants. If you grow sugar cane for fuels and materials, you will need other land for food. So has the switch really offered a net environmental benefit over fossil-based materials? What might be more environmentally sustainable, however, is to shift the value seen in the material, or extract more from it than originally thought. For example, with sugar cane, you can eat it, but you can also extract the sugars or other molecules from the waste materials.
We also have sugar beets in Europe, which we have looked at to see if that would be a good option to make fuels and materials. But again, there are the materials needed to grow the beets, so that creates impacts that need to be taken into account. In the first studies on bio-based materials, a lot of these effects were neglected. Then they said, ‘Okay, these are more environmental friendly than the fossil-based ones’. But the more and more researchers dived into this, taking into account all the effects of agriculture –the transport, preparation of the land, all those kind of things – then the question becomes is that material better in terms of greenhouse gas emissions than the fossil-based material?
What are the key take-home messages?
I would advise people to do the checks or calculations to see where you can reduce impact before you bring something to the market or before you fully develop the products.
A lot of people do sustainability assessment as a kind of last step in product development, but then you cannot change a lot of things anymore because you already invested in a certain process or certain upscaling. We work with partners in the research and development stages to see if we can choose the most environmentally friendly options at early stages of development.
Who should people partner with?
We use multi-disciplinary teams to do these projects. My colleagues in polymer science have their own reasoning for choosing certain options, and we come up with different information to add to that – then their selection will be based on more criteria than only what is the easiest synthesis route, for instance. Sometimes that coincides with the more environmentally friendly option. But now you see that if you really want to make big steps, these intuitive options are not always the best ones.
Yvonne van der Meer is Group Leader, Sustainability of Bio-based Materials in a Circular Economy, Maastricht University, Netherlands.